Life and Living Cells are tiny building blocks that make up all living organisms. Most cells cannot be seen with the naked eye and can only be seen using a microscope, i. they are microscopic. However, there are certain cells in nature that can be seen with the unaided eye, e.g. the eggs of fish, frogs and birds. ‘Some organisms are made up of a single cell and are called unicellular ‘Amoeba and bacteria. Organisms made up of many cells are called multi-cellular or macroscopic organisms, e.g. trees, humans, birds organisms, ©. and cats. Unicellular organisms Cell Structure ‘Mutti-celtular organisms There are basically two kinds of cells: plant cells and animal cells. Structures within cells are called organelles. APlant Cell cell wall + Forms the outer covering of a plant cal, “+ Made up of caluiose and is non.ving, + Very rigid and strong giving support, cell membrane. + Eneloses the contents af he cal + Allows certain substances lo enter ‘and entthe call andis thus. semi- pormeable or selectively permeable vacuole. + Asc within the cal ited with a fut calles cel sap, + Gell sep contains water, cissolved fead, mineral sals and waste material + Provides suppor tothe plant and is @ storage organ. cytoplasm/cytosol + Jolyske subsiance within the col where many chemical reactions take place, + Contain al the orgenetes ofthe call. Natural Sciences 9 chloroplast + Gontains the green pigment hloropy + Chiorophyl absoras suntight for photosynthesis. mitochondrion “+ Responsible fr the pracess of cellar respiration + During this process foods broken down to elease energy, nucleus Diagram of a Plant Cell Oairghs eserves + Contos al the activites of the cel Contains DNA (ceoryribonuctoie acid), whieh caries heraitay chargelarisies suchas eye colour, hha eo6ur ana height ONA'S tnigue fo each person and this vanaton enables nciiguas win 2 species tobe aiferent. + The nucleus is enclosed by a nuclear membrane. P|‘An Animal Cell mitochondrion cell membrane cytosol food vacuole. vacuole nucleus | Diagram of an Animal Cell Differences between Plant and Animal cells Plant Cell Animal Ceil 1, Has a cel wal Ne callwallpresent. | 2, Has chloroplasts 2. No chloroplaste present 3. Has a gid shave 3. Has a flenble iregular shape. 4. Large vacuole present. 4, Vacuoles are small, temporary of absent Cells, Tissues, Organs and Systems Celis are the building blocks of life. A group of similar cells working together is called a tissue. All the cells in a tissue look the same and perform the same function, e.g. muscle cells are able to contract and bring about movement. ‘A group of diferent tissues working together to carry out a specific function is known as an organ. The heart, stomach and lungs are all organs. Different organs work together to form a body system. The heart, blood and blood vessels all work together to form the circulatory system All body systems together make up a living organism. La 2 daa ce 4 I aa § Stem cells are a speciel group of cells that have the ability to develop into ‘numberof diferent organs different specialised calls, e.g. a slem cell can form heart cells or skin cells. They are found in the very eatly stages of embryonic development. Adult bone marrow also contains stem cells. — system y ‘number of systems The human body is made up of the following systems that work together to bring about @ balance in the body: > The Digestive System > The Circulatory System > The Respiratory System > The Musculoskeletal System ‘organism > The Excretory System » The Nervous System > The Reproductive System. i 7 2 Al rights reserved Natural Sciences1, The Digestive System The digestive system breaks down food into small particles (molecules) so that it can be ebsorbed into the bloodstream and transported throughout the body. The importance of food « Tt provides the body with energy. + It supplies the body with materials for growth. + Has nutrients that repairs and replaces damaged tissue. + Protects the body from diseases and infections. ‘The Digestive System is made up of: 4. The Alimentary Canal: which is a long tube extending from the mouth to the anus. itis made up of the mouth cavity, oesophagus, stomach, small intestine, large intestine, rectum and anus. 2. The Associated Organs: which assist in the digestion process - the teeth, tongue, liver and pancreas. ‘The following processes occiirin the digestive system. Ingestion: the taking in of food through the mouth Mechanical digestion: the physical breakdown of food by the teeth and the muscles of the stomach walls, Chemical digestion: the breakdown of food using chemical substances called enzymes. In the stomach hydrochloric acid is also used to breakdown food. Absorption: the movement of dissolved nutrients from the small intestines into the blood stream. gestion: the removal of undigested food and waste material from the body, via the anus (defaecation). Path of food along the alimentary canal Mouth > Oesophagus —> Stomach —> Small Intestine > Large Intestine —> Rectum—> Anus The Structure of the Digestive System mouth cavity “+ Teoth chew and crush te food. + Tongue moves the food inside the ‘oesophagus snout and es th he al “Lom tbe tha connect ne mouth + Tangue ass in swalloning foc. toi stomach «The muscles inthe walls contact anv ala, pushing the ooo towards the siomach. liver + Secrtes bile whic is stored in : ‘stomach the gal blader. : ih + Muscular sactike organ. 1 Has digasivejlces containing enzymes and hydrochloric acd tshich parsly break down food. + Parlay gested focd forms a thick liqus called chymo gail bladder + Siows bil + Bile assists in the cigoston of fots in the smal intestine pancreas small intestine : *Tongue-shape structure found + Chyme fom he stomach enters smal . eto he stomach, inatine oe 4 + Seeraes digestive luce ito the + Digestive juices socete tho wal ofthe ‘smal intestine which continue ‘small intestine digest chyme into molecules. iy ‘gesting chyms, then ae thon absorbed Int te 00d ‘ large intestine (colon) cppendix + Muscular tube that extends from the nal ifetine to the ans. rectum + Serves as a temporary storage piace ce fetinigsed ns hat + Egests faeces out ofthe body The Digestive System Natural Sciences 9 3A Balanced Diet ‘Abalanced diet is made up of all the essential food groups in sufficient quantities. The following represents the essential food groups required by the body: 1. Carbohydrates 2. Proteins 3. Fats and oils, 4, Fibre 5, Vitamins and minerals Carbohysirates Carbohydrates are the body's main source of energy. Starch and sugars ‘such as glucose; are examples of carbohydrates. souress of carbohydrates. proteins. The cells In the body are made up mostly of proteins. The body needs proteins to make new cells during growth and to replace worn out or Bread, rice, maize and chocolates are || demaged cells. Fish, meat, eggs end beans are rich in | |sKin act as an insulstor and reduces Fats and Oils, Fats (From animals) and oils (fom fish and plants) are @ rich source of energy. The body stores fal 2s reserve energy. Fat Is stored under the skin and around the heert and kidneys. Fat under the heat loss from the body. Cheese, chips and nuts are rich in fat, wah Fibre of roughage comes from piant material. Foods that are high in fre Include bran cereals, sweet com and Celery. Fibre cannot be digested but itis an important part (of our diet for the following reasons: + It prevents constipation, + Absorbs poisonous substances from the digestive system. + High fibre diets reduce the risk of heart disease, bowel (colon) eancer and decrease cholesterol in the body. Vitamins and Minerals ‘Vitamins and minerals are needed in very small quantitios| in our daily diet but are essential for good health. Deficiency diseases are caused when the body does not have enough of a particular type of vitamin or mineral, for ‘example, anaemia is caused by a lack of iron. Vitamin C is essential for preventing colds and "fy; calcium is essential for the development and maintenance of healthy bones and teeth, Fruit, vegetables and cereals are a sich source of vitamins ‘and minerals Importance of water Water makes up approximately 70% of our body mass. Water is taken in when food and fluids are consumed. Water plays an important role in that: « It provides a medium for chemical reactions to take place in the cells, + Itremoves waste material from the body via sweat and urine. « Itis @ major component of blood, which transports dissolved substances around the body. ‘+ When sweat evaporales it cools the body. 4 ©aAlrights reserved Natural Sciences !‘}Mainutrition Malnutrition refers to the harmful effects of eating too little, too much or eating the wrong kinds of food. ‘The table below show some ofthe eating disorders brought about by malnutrition. Disease Cause ‘Symptoms i Kiwashiorkor | Too ite protein inthe tet. «Bloated stomach, Cracked skin Marasmas — | The most common form of malnutrition, [> Lack of muscie tissue, ‘caused by (0 litle food, -the body | Thin slickelke body. ‘consumes its own tissues for energy. | | Anorexia Psychological condition where a @ Loss of body mass. | 5 person refuses to eat « Sterility in young women, } Obesity Eating too much energy rich foods. |» Increase in body mass. | 2 High blood pressure, heart disease. \ 2 Diabetes. Health issues related to the digestive system 4. Ulcers Gastric ulcers appear when the inner wall of the stomach becomes damaged. Gastric ulcers may also be caused by a bacterium which can be treated with antibiotics. Psychological stress and excess acid secretion may encourage the development of gastric ulcers. < 2. Diarrhoea Diarthoéa is the frequent passing of watery faeces (stools) which can lead to severe dehydration. Other symptoms include fever, vomiting and stomach cramps. It can be caused by viral or bacterial infections (gastroenteritis) and food poisoning, If eft untreated, diarrheca can lead to deat, especially in infants and small children, 3, Cirrhosis of the liver Cirrhosis is the scarring of the liver tissue. Scar tissue blocks the normal blaod flow through the liver. Some of the major causes of cirrhosis of the liver include: + Chronic alcoholism. * Viral infection such as hepatitis B, C and D + Fatty liver diseases caused by obesity and diabetes. Anormal liver Cirrhosis of the liver Natural Sciences 9 At rights reserved 5The circulatory system transports nutrients and oxygen to all the body cells, and also transports waste substances away from the cells to the excretory organs, The circulatory system is made up of the following structures: * Blood + Heart + Blood vessels, Blood Blood is a fluid tissue and consists of: + blood plasma (carries dissolved nutrients, waste products and gases, like carbon dioxide) + red blood cells (carry oxygen and ‘some carbon dioxide) + white blood cells (fight germs) + blood platelets (heal wounds by assisting in clotting) red blaad corpuscles Constituents of blood The circulatory system The Heart ‘The heart is a muscular organ located in the chest cavity, between the lungs. The muscular walls enable it to 8 a pump and force blood throughout the body. The heart is divided into four chambers. The two upper chambers, called atria (singular: atrium), receive blood {rom veins entering the heart. The two lower chambers (ventricles) pump the blood out of the heart via arteries aorta + Largest artery in the bod superior vena cxva——— * Tampons ongenetd Bod at * Brings deoxygenated blood anspor ong {tom upper paris of body. . 7 pulmonary arte left atrium + Rangpotsdoongetaed *Coteels axygenated blood fom ings. right atrium. * Cotects deonygonated pulmonary veins boos tam tha Body Bring oxypensie bod rom ings tricuspid valve vane + Proves bactow « * Prevents baton of blood ofbioos left ventricle « : + Has thick muscular wal to pump right ventricte ‘exygonated bloc teugh the sorta, + Pumps deonygenated toallpans ofthe body blood tounge. . apie Separaies ft (oxygenated blood) 8 rg ]exygenate bleed) haves of heat pericardium * Membrane that encloses and protects Internal structure of the heart the heert inferior vena cave- + Brings deoxygenated blood Irom lower pars of body, 6 @arrights reserves Natural Sciences!deoxygenated blood from ' i iecsygenaio hood fo | oxygenated biood to all pars of the body superior vena cava- aorta ‘deoxygenated biodd to lungs deoxygenated blood to unas left atrium pulmonary artery: ‘oxygenated bi6od from luros pulmonary veins right atrium t= oxygenaied blood from lungs ‘tricuspid valve- bicuspid valve left ventricle right ventricle. inferior vena cava deoxygenated blood irom ower parts of the body” Blood flow through the heart Blood vessels Blood vessels are tubes that transport blood o Capileries «Seen angen wae pee throughout the body. There are three types bhi eabon date tees the of blood vessels: blood anc body cots, 1 Artery " + Cary blood away rom the heart. vai + Allanteries, except for the ‘ V} pulmonary artery. cary . é * Cary blood towards the haat. ‘xygenated blood , + Aliveine, except te pulmaary ‘alps, cary deoxygenated blood. Typos of blood vessels Health issues associated with the circulatory system 4. High blood pressure High blood pressure, also called hypertension, is a medical condition where the pressure of the blood in the arteries is raised, This increases the workload of the heart, which may lead to a heart attack, stroke or organ damage, e.g. kidney failure. } 2. Heart attack ‘Most heart attacks are caused by a blockage in one of the arteries that supply blood to the heart muscle. That portion of the heart does not get sufficient oxygen which may result in permanent muscle datfiage. Some of the risk factors for heart attacks are smoking, obesity, high blood pressure and high cholesterol. Exercise and a healthy diet minimise the risk of a heart attack ‘blood vessals supplying the heat wit blood 3. Stroke Asstroke is a condition caused by a blockage in the blood flow to the brain or by the bursting of a blood vessel in the brain. This may also happen because of high blood pressure. A person suffering from a stroke may lose the ability to speak and may have memory problems. Parts of the body may become paralysed. Natural Sciences 9 ©Aw rights reserved 7} The respiratory system is responsible for supplying the body with oxygen and removing carbon dioxide. The { respiratory system and circulatory system work together to achieve this. Cells use oxygen during cellular | respiration and produce carbon dioxide as a waste product. nasal passage- | + Hairin nosis treat. Blood vossois warm sit {neue masts a epigiottis. + Structure that closes ‘pening to trachea when ‘swalowing. pleura + Mertbrane encosing bd potactg ngs ribs (rib cage). { + Prolects lungs itercostal muscles: + Move ribs o help with inhalation and extalation Jung + Spongy, cone-shapad organ. + Right ung has 3 lobes (sections), left ung has 2 lobes. I diaphragm + Msc on wih une ek {When raised ai foree oi exhalation) 2 Wen lowered alrushes in (rslaton). larynx «Ais known a8 vies box 1 Has vocal cord wnich ere cine wen sir forced trough tom C-shaped cartilaginous ring + Serves to keep trachea opon (as rotealanse) + us or expansion of ‘esophagus whan swallowing trachea + Passage for air into and aut of Jungs. + Has C-shaped carilage rings, os Secrotes mucus which taps dust + Gia crve out dustladen mucus, bronchus * Allows airin and out af each lung bronchiole + Small tubs leading oir sacs, (alveat. ‘alyeolus *Cup-shaped pouch + SurTounted by network of pllares + Sile of gaseous exchange, The Respiratory System Difference between Breathing, Gaseous Exchange and Cellular Respiration Breathing i Breathing is a physical process involving: Inhalation which occurs when air taken into the lungs. The diaphragm contracts and lations; the intercostal muscles contract causing the chest to ‘expand. Air rushes into the lung. Exhatation which occurs when alr is removed from the lungs. The diaphragm relaxes and bulges upwards; the intercostal muscles relax, squeezing the lungs. The chest retums to its normal size. Inhalation 8 @©airghis reserved Neural Sciences 9Gaseous Exchange Gaseous exchange occurs at two places in the body. «In the lungs, oxygen diffuses from the alveoli into the blood and carbon dioxide diffuses from the blood into the alveoli + In the body tissues, oxygen diffuses from the blood into the cells and carbon dioxide diffuses from the galls into the blood. Gaseous exchange at the tissue level of Gas exchange in the lungs 0, C0, Cellular Respiration Cellular respiration is a chemical process that occurs in the mitochondria ‘and involves the breakdown of food to release energy. During the process oxygen is used and carbon dioxide is released as a by product. The energy that is released is used for other processes in the body. Health issues associated with the respiratory system 4. Asthma Asthma is caused by the cor inthe lung, Breathing bécomes difficull because alr ~ ‘cannot effer and exit the iungs freely. Asthma symptoms include severe coughing, wheezing and chest tightness. Normal bronchiole Asthmatic bronchiole 2. Bronchitis -tis means infamation) Bronchitis is caused by exposure to infectious micro-organisms or air pollution. This results in the build up of mucus in the bronchioles. The mucus prevents the free movement of air into the lungs and breathing becomes difficult, mucus 3. Asbestosis 4, Cancer of the lungs Asbestosis is a lung disease that arises from breathing _Smokingyis one of the main causes of cancer of in asbestos fibres, This causes severe chest pain, the lung. Tumours develop in the lung tissue coughing, and shortness of breath, Asbestos mine which bldck the movement of air into and out of workers frequently suffer from asbestosis. the lungs. Natural Sciencos 9 ©a¥ ght eserves 9| (teasers : ‘The musculo-skeletal system is made up of muscles, bones, cartilage, tendons and ligaments. Connective tissu t binds the different components together. ‘The muscuo-skeletal system Is made up of two distinct systems: the muscular system and the skeletal system, Muscular System ‘Skeletal System Functions of the musculo-skeletal syster «+ The skeleton provides a framework for holding the body upright (support). + The skeleton and muscles work together to maintain body posture. j + The skeleton and muscles work together to bring about movement. + Protect vital organs: (refer diagram) ‘Skull protects the brain, D | Rib cage protects the | heart and lungs. ‘Abdominal muscles protect ! Pelvis protects parts of the fs eee urinary and reproductive systoms. &% 8 The Musculo-Skeletal system 10 OAK rignis reserves Natural Science.| Structures associated with the musculo-skeletal system | Ajoint is a place where two or more bones meet. A joint allows for the different jssue | types of movement in the body. Examples of joints in the body: elbow joint, knee | ioint, hip joint, neck joint, shoulder joint. | Asoft and floxible type of tissue called cartilage is found at the ends of the {vone. Cartage prevents bones fom rubbing against eat other, Le prevents friction, | Ligaments are flexible structures thal join bone to bone, preventing dislocation fata joint. | Tendons connect muscle to bone, enabling the bones fo move. When muscles | contract, they move the bones which are attached at the joint and this brings | about movement. tendons Akneo joint Friceps (relaxed) load : fulcrum i (elbow joins) The arm as a 3rd class lever | ust ofthe upperarm | |Health issues that affect the musculo-skeletal system 11. Rickets 3, Osteoporosis (ostaa means tone) | Rickels is a disorder of the skeleton * Osteoporosis is a condition which is caused by a | caused by a deficiency of vitamin D, | = decrease in the bone density. The bones lose their | calelum, phosphonis ora lack of strength and become fragile. This results in frequent | exposure to sunlight. Rickets results fractures (breaks) of the bones. Osteoporosis is | inthe softening and weakening of ‘common in elderly women. | the bones. Bones tend to bend, “Teading to a child being bow-legged ‘or knock-kneed. It tends to affect children 8-24 months of age. 4. Fractures A fracture is a partial or complete break in the bone. Fractures are due lo extreme forces being exerted on the 4 2. Arthritis (artiro means faint, tts means inflamatlon) Arthritis is the inflammation of one or more joints in | the body. Symptoms of arthritis include severe pain and limited function of the joints. WY Normaljoints _Arthritic joints | Natural Sciences 9 : ©atrignh vesarved bone. They can be caused by direct blows, twisting injuries or falls. Xray of a fractured thigh bone il“The chemical reactions that take place in the body produce a variety of waste products such as CO,, ures, uric acid and ammonia, The accumulation of these waste products within the calls would prevent the normal functioning of the body. Excretion is the removal of waste material from the body. Several organs are responsible for excretion: i 1 a a i | 9 Excretes: Sweat which contains ‘some water in the form of wator urea, uric acid, ammonia, excess The Urinary System ‘The urinary system is made up of the two kidneys, two ureters, bladder, urethra and the blood vessels. The main functions of the urinary system are to remove waste from the blood and to regulate the composition of body fl fluids, i | urea, exc0ss salts and water. vapour. falls and water orte. + Carias blood avray from the heart to the lower regions of the body. renal artery inferior vena cava: + Carries bioad, with wastes, + Caries blood back to tne heat. to the icneys. right kidney- « Fiters blood by removing wastes and forms wine renal vein + Caries blood, res of wastes, away from the kidneys SS “Caries urna fom the kidneys to the bladder renal capsule * Mambrane thal encioses ‘nd proteets wach Nanay bladder + Slores rin, urethra + Tube allowing urine to pass ‘ut ofthe body. The Urinary System 12 QOaArights reserved Natural Sciences 9aes Functioning of the kidney + Blood in the renal artery, although oxygenated, has wastes produced by the cells of the body. + Blood enters the kidney where specialised structures remove dissolved substances (filtration), from the blood to form a filtrate. + Useful substances then diffuse from the ftrate back into the blood (reabsorption). + The wastes that are dissolved in the excess water form urine, which is sent along the ureter to the bladder, where itis temporarily stored and eventually eliminated during urination, + Blood, with its wastes removed, is sent through the renal vein to the inferior vena cava. The renal ve deoxygenated blood (having supplied the kidney with oxygen and removed carbon dioxide). cai Specialised structures within the Hanoy Blood, containing waste » file cut Sesloved eubstances products, enters the kidney (Girton). rough the renal arary. » reabsorb useful substances {teabsorpiion). 5 » send wastes, excess salts and [Biood, with ts wastes removed [sceodeabeaadonnel ows back tough the renal vein tothe hear. > 7 [Wastes (urea, ue acid, ammon: salts) disolved in water, frm urine, which is sant down the ureter to tha bladder, Functioning of the kidney Health issues associated with the urinary system 1. Kidney stones Kidney stones form from salts which are present in the urine, The salts crystalise, forming “stones”, which can grow with time and cause @ blockage of the ureter. Kidney stones can be removed through surgery or broken down into fine particles by laser treatment Kidney with stone (receiving laser treatment) 2. Kidney infections Kidney infections are generally caused by bacteria. Bacterial infections start in the bladder and spread to the kidneys. Kidney and bladder infections can be treated with antibiotics. 3. Kidney failure Kidney failure results when the kidneys can no longer remove waste material from the blood. Kidney failure can result in death. Kidney dialysis is a treatment given to patients with kidney fallure. During this treatment a dialysis ‘machine is used to remove waste material from the blood. Natural Sciences 9 ©Alrighs reserved 13Brain; mass of soft ssue that is protested by the skull and by three membranes, or meninges, that ‘Surround ta bean. The nervous system is a complex system that co- ordinates the different activities of the body and enables the body to interact with its environment. The nervous system is made up two parts: 4. Central Nervous System (CNS): which is made up of the brain and the spinal cord. 2, Peripheral Nervous System (PNS): comprises all the nerves that connect the brain and spinal cord to the rest of the body. ens Spinal cord: long, cynical structure that extend from tho base] ofthe brain dawn the back thraugh ® canal nthe vertsoral column, non of nerves coma he le 2 : 2 brain and spinal cord o all parts of the bouy, The Nervous System ‘Sense Organs and Stimuli ‘The nervous system enables humans to detect changes in their surroundings and react to them. Changes in the environment are called stimuli and these stimuli are picked up by special nerve cells called receptors. These receptors are located in the sense organs. Nose Tongue ‘Skin Taste “Taueh, pressure, pala Sight Hearing and balance ‘Smell (sweet, salty, bitter, sour)| | and temperature (heat) Health issues associated with the nervous system 1. Deatness Deafness, or impaired hearing, is a partial or complete loss of hearing. Damage to the receptor cells in the ear, disease of infections can lead to hearing loss. When a person is deaf, messages from the ear cannot reach the brain for interpretation. 2. Blindness ‘The eye has special nerves to send messages to the brain, so that the brain can process and recognise what is being seen. If hese messages do not reach the brain a person may be visually impaired, or blind 14 Oat rights re / Natural Sciences 9LK 3, Short-sightedness and far-sightedness When light enters the eye, an image is formed at the back of the eye which is interpreted by the brain, When this image falls short of the back of the eye, the brain cannot interpret the image clearly and blurring accurs. Ifthe image falls beyond the back of the eye, blurring also occurs, resulting in far- of long-sightedness. Both short-sightedness and long-sightedness can be corrected with glasses, contact lenses or surgery. front Image sharply Image in fogs bured image image in focus 4 Ipeyend back oe Normal vision Short-sightedness Far-sightedness a 7 4. Effects of aleohol on the Central Nervous System (CNS) Alcohol is a drug which affects the nervous system. Alcohol can cause: + difficulty in walking + blurred vision « slurred speech ‘slow reaction times + impaired memory ‘= impaired judgement. Drinking large amounts of alcohol for long periods of time can lead to serious and permanent damage to the brain. 5, Effect of drugs on the central nervous system Drugs can be classified according to the effect that they have on the central nervous system. The brain Is the major part of the central nervous system and this is where drugs have their main effect. Table showing common drugs and thelr effect on the Central Nervous System Drug Effect Dagga afiects the blood supply to the brain and results in decreased Pagga | concentration, memory loss and impaired judgement. Heroin is one of the most addictive and deadliest of crug, In the Heroin | brain, heroin changes to morphine which creates a feeling of ‘euphoria (happiness). Heroin addiction results in mental retardation Ecstasy (the party drug), speeds up activity in the nervous system. Ecstasy | Users stay awake and are full of eneray for along time. The drug damages nerve and brain cells. ‘Also knawn as crystal meth, tk gives a person a feeling of increased Tk ‘energy, but in the process damages the brain cells. Long term use of| {ik results in memory loss and tremors (‘shaking hands’) Natural Sciences 9 Ar rights reservedReproduction takes place so that species do not become extinct. The main function of the reproductive system is to produce male and female sex calls called gametes. the stage in the life cycle when a boy or a girl becomes sexually mature, i. they are able to reproduce. Puberty usually occurs between ages 10 and 14 for girls and ages 12 and 16 for boys. During puberty, chemicals substances called hormones are released into the blood, which cause physical changes to the body. Structure of the male reproductive system ‘The function of the male reproductive system is to: + Produce male sex cells called sperm cells «+ Ensure that the sperm cells are successfully transferred into the female body. ‘+ Produce the male sex hormone called testosterone which is responsible for male characteristics such as facial hair, pubic hair and deepening of the voice. bladder + stores urna rectum penis ‘ + Used to transfar sperm into the vagina. i urethra: + Tube through which sperm or urine passes. serotun $$ + Sactike etrucure that protects testes. sperm duct + Corres sperm away from the testes. ‘testis - Produces sperm cals, + Produces the homrane testerone. The Male Reproductive System tal “for swimming ‘The male gamete (sperm) The male sex call is called a sperm cell or spermatozoon, Spermatozoa are formed in the testes. When sperm is being transferred into the female, they travel through the sperm duct, and mix with nutrients and fluid along the way. The resultant mixture Is called semen. Sperm cells have a long tail which has a whip-ike action that enables them to swim, The head of the sperm cell contains all the genetic information of the father which will be passed on to the offspring. heed * carries genetic information A spermatozoon Structure of the female reproductive system The function of the female reproductive system is to: + Produce female sex cells called egg cells or ova (singular: ovum). « Release female sex hormones (oestrogen and progesterone). Oestrogen is responsible for female characteristics suct’as menstruation, breast development and pubic hair. Progesterone maintains the period of pregnancy. « Protect and nourishes the fertilised egg until the baby is fully developed during pregnancy. 16 args reserved Natural Sciences 9oviduct (Gallopicn tube) * Tube afowing avum to ‘move from ovary 10. Utes. uterus + Made up ofa muscular wall + Enirance tothe & e «+ Site far aragnancy, uterus. vagina, + Receives sperm fom the mate. + Aigo hnown asthe bith canal The Female Reproductive System The female gamete (egg cell/ovum) ‘The egg cell or ovum is produced in the ovaries. One ovum is released once every 28 days and this process is calied ovulation. The ovum carries all the genetic information of the mother which will be passed to the offspring if fertilisation occurs. Menstruation ‘Toward the end of puberty, gitls begin to release eggs as part of a monthly period called the menstrual cycle. Approximately once a month, during ovulation, an ovary sends an ovum into one of the fallopian tubes. During this time the walls of the uterus thicken in preparation for pregnancy. If the egg is not ferilised it disintegrates and together with the inner lining of the uterus wall, leaves through the vagina. This process is called menstruation. Menstruation in most women lasts from 3 to 5 days. Fertilisation During sexual intercourse (copulation) the male places his erect penis inside the vagina. Semen is then released into the vagina, this is called ejaculation. The sperm cells swim up the vagina, through the uterus, towards the oviduct or fallopian tube. If there is an egg in the oviduct, a sperm cell will fuse (join) with it and fertilise the egg. Fertilisation is the first stage of pregnancy. Pregnancy (Gestation) A fertilised egg cell is called a zygote. It contains the genetic information of both parents. The zygote undergoes continuous cell division to form a ball of calls called the embryo. The embryo moves towards the uterus and becomes attached to the uterus wall, this process is called implantation. The embryo develops into a foetus and remains in the uterus for 40 weeks where it develops into a baby, this is called the period of pregnancy. The embryo gets all its nutrients from the mother through the placenta and the umbilical cord. The placenta allows oxygen and nutrients from the mother’s biood to diffuse into the embryo's blood supply. Waste material from the baby is removed through the umbilical cord and diffuses back into the mother's blood via the placenta. Contraception Contraception refers to the different methods of preventing a sperm cell from fertilising an egg cell. Pregnancy can be prevented by using contraceptives like the condom or the pill. Condoms also prevent the transmission of HIVIAIDS and other STDs (sexually transmitted ciseases). Health issues affecting the reproductive system 41. Sexually transmitted diseases (STDs) ASTD is any infection or disease that is passed from one individual to another during sexual intercourse. There are many STDs including AIDS/HIV, gonorthoea, syphilis and herpes. Some STDs can result in the person becoming infertile, which means that the infected individual cannot have a baby. 2, Foetal alcohol syndrome Fostal alcohol syndrome (FAS) is a disorder in children that is due to the mother consuming alcohol during her pregnancy. The child shows characteristic fecal, limb and heart abnormalities. The development ofthe foetus is delayed and mental retardation is common, Natural Sciences 9 As igh reserved 17Questions | Question 1 Provide the correct term for each of the following : The smallest, structural and functional unit of the body. olls that cannot be seen with the naked eye. ells that can be seen with the naked eye. Organisms that are made up of one cell only. ‘Outermost layer of a plant cel Outermost layer of an animal cel. Organelle within plant cells that contains cell sap. Jelly-ike part ofthe cell that contains all the organelles ff the col. 9. Organetle that controls all the activities ofthe cel. 10. Chlorophyl-containing organelle in plant cells. 111. Organelle responsible for the process of cellular respiration, 12. A group of similar cells which together perform the ‘same function, 13, A group of diferent tissues working together to carry out fa specie function. 14. group of different organs which work together make upa 415. Asspecial group of cells that have the ability io develop into different specialised cells. (18) ‘Question 2 ‘Study the olagram below and then answer the questions that fli Is the above cella plant cell or animal cell? Provide: TWO OBSERVABLE reasons for your answer. (3) 2. Provide labels for A to F. 6) 3. List ONE function ofthe part labelled aA bye oF 6) 4, Write down the LETTER of the part that: a) Stores water end dissoived nutrients b) stores food Question 1 Name the part that is used to: 4, luminate the specimen. 2. hold slide on the stage. 3. magnify specimen being studied. 4. control light intensity. 5. hold the eyepiece. 6. place the slide to be viewed 7. bring specimen into focus. 8. hold when carrying the microscope when 9. concentrate light onto specimen, 10, bring specimen sharply into focus. (10) Question 2 Calculate the magnification of an onion cell f the eyepiece has a magnification of 10 and the objective, a magnification of 20. @ Question 3 1. Provide labels for the paris labelled A to L. (12) c) contains DNA 6) 5, Tell 4 sflerencesbebeon pla as nd anna cells. (8) 18 @as pis reserved Natural Sciences 8Question 1 Provide the correct term for each of the following 1. The taking in of food through the mouth. 2. The physical breakdown of food by the teeth and the muscies of the stomach walls. 3. The breakdown of food by enzymes, 4. The movement of dissolved nutrients from the small Intestines into the bloodstream. 5. The removal of undigested waste from the alimentary canal 6. Opening to the alimentary canal 7. Structure within the mouth that mixes food with salva. 8, Structure within the moath that assists in the swallowing of food, 8. Organ of the digestive system that secretes bile 40. Structure that stores bile. 7. Part of the digestive system where final digestion and absorption of food takes place. 42, Long lube that connects the mouth to the stomach, 419. Muscular, sac-ike organ containing chyme, 14, Organ of digestive system that contains hydrochloric acid, 18. Part of digestive system with acidic pH. 16. Liver secretion that assists In the digestion of fat. 17. Leaf-shaped organ found behind the stomach. 18, Partially digested food in a semi-solid form in the stomach. 19, Opening through which undigested waste leaves the body, 20. Muscular tube that extends from the small intestine to the anus, 24. Structure that serves as a temporary storage place for undigested waste, 22. Foods that are the body's main source of energy. 23. Indigestibie material found in plant cell walls that prevent constipation, 24, Foods that are required by the body to assist with repair of damaged or worn out calls, _25.Foods that act as a reserve energy source. 26. condition that results when's balanced diet is not followed, 27. Disease caused from a diet consisting of energy rich foods. 28. Disease that results from a diet rich in carbohydrates ‘but lacking in protein. 29, Disease characterised by 2 lack of muscle tissue and thin stick-ike body. 20. Scarring ofthe liver issue as a result of consuming too ‘much aleoho! (39) avesionn T Study the structure of the human digostive system then ‘answer the questions that follow: Natural Sciences 9 FE e 1. Provice labels tor Ato K. a) 2 Write down ONE function of the part labelled a) be oA aE 8) 3, Provide the LETTER of the part that: a) contains hydrochloric acid b) serves as a temporary storage place for undigested waste ©) stores bile 4) aids in swallowing fe) Serves no function in the digestive system (5) 4, Sludy the table bolow. Write dawn the letters a to nin your answer book and next to each letter write down the correct answer, Ca) [orem] —swuPTows CARE von ety and (=) [sores su ® @ @ Tiree [Diarrhoea (e) o (9) [increase in body mass. (h) Sos and excss 0 o lecetons ithe ter 0 (i) |tackof muscle issue. o 5. List tivo teasons why water Is essential in our bodies. (2) @Oarights reserved 19‘Question 1 Provide the correct term for each of the folowing : 1, Thin.walled blood vessels that allow diffusion to take + place. 2. Vessels that transport oxygenated blood from the lungs to the heart. ‘A medical condition where blood pressure is above normal fis . Vessel that carries oxygenated biood out of the heart. ‘Vessels that transport deoxygenated blood from the heart to the lungs. Valve between the left atrium and left ventricle. Vessel that transports deoxygenated blood from the upper paris ofthe body to the heart. 8., Chamber that receives oxygenated blood from the lungs. [9. Lower chambers of the heart. 10. Valve batween the right atrium and right ventricle, 11. Membrane that encloses the heart. _-A2. Upper chambers of heart. 43, Pumps deoxygenated biood to the lungs. 14, Vessel that transports deoxygenated blood from lower pars of the body to the heart 415, Liquid part ofthe blood that carries dissolved nutrients ‘and carbon dioxide. 16, Wall that separates left and right halves of the heart, 17. Blood cells that carry moslly oxygen and some carbon dioxide. 418, Largest artery in the body. 219. Blood cells that fight germs. 20. Chamber that receives deoxygenated blood from the body. 0) ‘Question 2 ‘The diagram below shows the intemal structure of the human heart. Study the diagram and then fi in the labels from Ato M. (13) 20 QA ahs reserved Question 3 Complete ve lable alow by wing tre correct answer in your answer book © SSeASE| Suro CASE Stroke (a) (e) Siecure oft boadin © [itertce erased. @ Blockage w one of the actories that supply blood to] Ihe heart muscle (C) 0 Question 1 Provide the correct term for each of the fllowing 1. Structure thet closes the opening tothe trachea when swallowing. 2. Scientific name for the voice box. 3, Membrane enciosing and protecting the lungs. 4. Dome-shaped muscle that separates the chest cavity from the abdominal cavity 5. Cup-shaped air sac. ®) Question 2 Study the diagram of the human respiratory system below and provide labels for Ata L. (12) Question 3 Explain the following terms: a) breathing bb) gaseous exchange ©) cellular respiration ©) Natural Sciences 9Holiday Nem wo se Question 4 Provide the correct termn for each of the follawing 1. Aplace where two or more bones meet. 2. Sof, flexible tissue found at the ends of bones that Prevent friction ‘Afiexible type of issue that connects muscle to bone. Muscle in the upper arm that raises the lower arm when itcontracts, 5. Flexible structures that join bone to bone preventing dislocation. ‘6. Muscle in the upper arm that pulls the tower arm away from the body when it contracts. © Question 2 (One of the functions of the musculo-skeletal system is to protect vital organs. Complete the table below by filing in the missing information, Write the correct answers in your ‘answer book @) ‘STRUCTURE ORGANS PROTECTED Skul @) ibcage ( @ intestines Pavia ‘a ‘Question 4 Provide the correct term for each of the following: The removal of waste products from the body. ‘Membrane that encloses and protects each kidney. Vessel that carries blood with wastes to the kidney. ‘Tube that carries urine from the Kidneys to the bladder. Vessel that carries blood free of wastes away from the kidneys. ‘Tube that allows urine to pass out ofthe body. ‘Structure that stores urine temporal eaene ” ‘Question 2 ‘Study the diagram of the human urinary system then answer the questions that follow: 1. Provide labels for Ato ® 2. List the functions of structures labelled aA bc 9D a6 e). (19) Natural Sciences 9 qQacko A ‘Question 3 Write down the LETTER of the structure that: a) stores urine temporarily b) carties blood back to the heart ©) encloses and protects the kidney 4) allows urine to flow out of the body ©} carries blood away from the kidnay 6 Question 1 Provide the correct term for each af the following: 4. Nervous system which is made up of the brain and spinal cord. 2. Mass of tissue protected by the meninges and skull 3. Long, cylindrical structure that extends from the base of the brain and down the back 4, Nervous system comprising all the nerves that connect the brain and spinal cord to the rest of the body. “ Question 2 Complete the table below by wrting the correct answers in your answer book 6) SENSE ORGAN FUNCTION Eye (@) ©) Hoang an balance Nese @ Skin @ © aslo ©atiights reserves 21Question 1 Provide the correct term for each ofthe folowing : 4. Stage inthe life cycle of @ person when they become _ sextaly mature 2." Male sex colts Siructue that produces mle sex cll. Chemical substances which cause physical changes in the body, . Tube thet carries sperm away fom the testes. ‘Siruelure in femalos that receives sperm from the male, 7. Hormane responsibi fr mle secondary sexual charactors. 8, Tube in which fertisaton occurs. 9, Sacclke structure that protects the testes, 40. Structure that produces ova. “Tbe Hough which sperm of ine passes fo the cutside of the body. 12. The female gamete. 13. Structure that houses the growing embryo. +4, Hormone responsibe for female secondary sexual characteris, 415, The breakdown and release of the lining ofthe uterus wall through the vagina 16.Fusion ofthe egg cell withthe sperm cel 47. Aferiised egg 48. Attachment ofthe embryo tothe uterus wal 19. Structure that allows nutrients and oxygen to difuse {rom mother's blood into the embryo's blood” 20. Structure that attaches embryo to the uterus wall. (21. The period from fertlisation until birth. 7%, Hormone that maintains the period of pregnancy. 23, Different methods of preventing pregnancy. 24. disease or infection that Is passed from one individual to another during sexual intercourse. 25, A disorder In children that is due to the mother ‘consuming alcohol during her pregnancy. (25) Question 2 4. Name THREE secondary sexual characteristics in a) males 3) b) females: @) 2, What Is the first sign of sexual maturity in: a) males a b) females a 3, The statements below refer to different methods of Question 3 Tho diagram below shows the intemal structure of the male reproductive system. 3) 1. Provide labels for Ato G. ” 2, List functions for parts labolied aya b) F 2S 6) 3. Write down the LETTER of the part that: 1) produces sperm b) carries sperm away from the testes €) that protects the testes. 6) Question 4 ‘The diagram below shows the nterel structure of the female reproductive system. (13) contraception, Match the stalements in Column t with | + Provide labe's for Ato E. © ‘he terms in Column 2. ; Set — 2 isto or pate ble 7: Raber sheath placed over the pais | A. Veseciomy DD ® 2, Gral mediation a prevent nian | 8. Wale condom 3, Culing and yng ofthe ovducls | C.Tubeigaion | | 2, Wre down the LETTER of the par thet: 4 Citing and ving af he vs deferens |B. Hysterectomy 2s a tube in which the ovum travels tothe uterus 5. Remaval of the uterus and Fallopian | E. Contraceptive b) praduces ova tubes ot 6} also known as the bith canal @ 22 Ati shis seve Natural Sciences 9md Materials 2 Matter The Atom All matter is made up of tiny particles called atoms. Atoms themselves are made up of the basic (sub-atomic) particles, namel * protons (positive charge) carbon dioxide Wor sqvaion = a Product C + O, > CO, vam cu tatomot “5 4 molecule ire ‘A molecule of Co WD CO Reactants SEUENDESEEEEIGEEEESETEISEDT=E( | ‘Product 2H, + O, - 2H,0 amolecues "4 motecule anal 2molecules Le So WD K& B. Balancing Equations A balanced equation is an equation in which the total number of each kind of atom on the reactants side (left side) is equal to the total number of each kind of atom on the products side (right hand side). Example: 2H, + O, > 2H,0 vom tne ie Gurhud 73 4 Natural Sciences 9 ©Alirehisresowved 27Steps to follow in balancing an equation Example Balance the following equation: H, + O, > HO 1, Make sure that the chemical formula for each substance is written correctly. You cannot change the chemical formula of either the reactants or the products. All you are required to dois to change the coefficients, if necessary, of each of the reactants and products. The coefficient of each of the reactants and products in the unbalanced equation is 1 2. Choose one element on the reactants side (left) and count the total number of atoms of that element on the reactants side; do the same for that element on the product side (right). Hydrogen: there are two atoms on the reactants side (left) and two atoms on the product side (right). The hydrogen appeers to be balanced (this may change Tater). ~ 3. Choose the next element on the reactants side and count the total reactants side; do the Same for that element on the product side. ‘Oxygen: there are two atoms on the left and only 1 on the right. Since we cannot change the chemical formula ofa-compound, we then place the coefficient 2 in front of HO, which will now read 2H,0, giving a total of 2 oxygen atoms. Oxygen is balanced. oa H, + O, > 2H,O 4. You must go back to the first element and check again (i.e. belance) just in case by changing the coefficient of oxygen the number of atoms of hydrogen has changed. ‘We now have 2 hydrogen atoms on the left and 4 hydrogen atoms on the right - not balanced. Now we change the coefficient of the hydrogen on the left io 2. The hydrogens ere now balanced. 2H, + O, > 2H,O 5. The last, but very important step: Check that each element is balanced by counting the number of each element on the reactants side as well as the product side. Left has 4 hydrogen atoms; right has 4 hydrogen atoms - hydrogens are balanced. Left has 2 oxygen atoms; right has 2 oxygen atoms - oxygens are balanced. ‘The equation is now balanced. If you follow these steps you will balance equations correctly evert time, | Another example: Al+O; > ALO, Balance Al: 1 onthe lf ane 2 on the right - not balanced. Balance by adding coefficient 2 in front of Al on the left. Af now baanced. 2Al+0, > ALO, Balance O: 2 on the left and 3 on the right. Add coatfciant 2 to the right, giving a total of 6 oxygens) on the right ie 2x3. (You cannot 2A1+0, > 2Al,0, use fractions as coefficients.) || We now have 6 O on the right but 2 0 on the left... add coefficient 2A1+30, > 2A\,0, 30 O.on the let, giving 6 © on tho loft and right, Problem i: we now have 4 Al onthe right but only 2 onthe ff Change the coefficient for Al from 2 to 4, 4A\+0; - 2A1,0, Check Al again: 4 onthe left and 4 on the right (2 x 2). aoe Ae Check All and © once more, 28 Qa igs reserves Natural Sciences 91 i ] | More examples copper + oxygen -> copper oxide Cu+0, + CuO | Balance Cus t on theleftand 1 onthe ight, Cuappoarstobe balanced, Cut, + Cud | i Balance O: 2 on the loft and only 1 (on the right. Add coefficient 2to the Fight, giving @ total of 2 oxygens) on the right. (You cannot use frections Cu+O, + 2Cu0 as coefficients.) Oxygens appear to be balanced, 2Cu+O, -» 2Cud Check Cu again: 1 on the lef but 2 on the right Add coofclent 2 to Cu on the et Check Cu and © once more. 2Cu+0, + 2Cu0 e Iron + oxygen iron oxide (rust) Fe + 0, > Fe,0, | Balance Fe: {on the laff and 2on the right. Add coeficient 2totheleR © Fe + O, > Fe,O, Fe, giving a total of2 Fe on the lent | Balance 0: 2 on the let but 3on the right Add coeficiont to the right, 2Fe + O, > Fe,0, | hen a fal 28 oxygens) on th, You cant ue econ 2s Coefficients.) Add coeficient 3 on the let, giving a total of 6 oxygens on the left. Oxygens appear to be balanced. 2Fe + 30, + 2Fe,0, (Check Fa again: 2 on the left but 4 on the right. Change coefficient 04 4Fe + 30, -» 2Fe,0. con the left. A Os ‘check Fe and © once mers. 4Fe + 30, > 2Fe,0, magnesium + oxygen > magnesium oxide Mg + 0, + MgO Balance Mg: 1 on the feft and 1 on the right. Mg appears tobe balanced. = Mg +O, -» MgO | — Balances O: 2 on the left and only 4 on the right. Add ooeffcient 2 to the Fight, giving @ total of 2 oxygens) on the right. Oxygens appear to be Mg +O, -» 2MgO balanced, / Check Mg again: 2 on the right but only 1 on the left. Add coefficient 2t0 = Mg + Mg on the left. ‘Mg 0, — .2MgO Check Mg and 0 once more 2Mg + 0, + 2MgO Natural Sciences 9 ©aringhts reserved 29Some metals react with oxygen during combustion (burning). A burning process means that energy is released during a the reaction. When a metal reacts with oxygen a metal oxide is produced. Solutions of metal oxides tend to be basic (high pH}. The general equation for this type of reaction: Metal + Oxygen — Metal oxide Reaction of Magnesium (Mg) with Oxygen Magnesium ribban bums in oxygen with a blinding white light to produce a white powder (magnesium oxide). ‘The white powdet dissolves in water forming an alkaline solution, Y magnesium + oxygen — magnesium oxide word equation Mg+ 0, + MgO Unbalanced chemicel equation 2Mg+ O, + 2MgO Balanced chemical equation Reaction of Iron (Fe) with Oxygen xron filings or ste! wool bums in oxygen (the oxygen part of alr) with a bright yellow lame and produces sparks. ‘Ablack solid substance (iron oxide) is produced. Iron + oxygen > iron oxide Word equation Fe + O, > Fe,0, Unbalanced chemical equation 4Fe + 30, > 2Fe,0, Bolanced chemical equation Formation of Rust When certain metals react with oxygen in the presence of moisture they corrode. Corrosion results in the metal becoming metal oxide which does not have the strength of the metal. The metal oxide resulls in the metal becoming weak and brittle. The corrosion of iron and steel (steel which consists mostly of iron) is called rusting due to the red-brown substance called rust on the surface of the metal. Modem construction uses equipment and structures made of stee! that can rust and weaken them. Measures have to be taken to prevent them from rusting. Ways to prevent rusting ‘+ Iron and steel can be painted to keep away ‘oxygen and moisture, + Iron and ste! can be coated with a thin layer of chromium or zine (metals which do not rust),This| is done by an electroplating technique which is a form of electrolysis. The "tin" roof as shown in the picture alongside is really iron coated with zinc. (Once the zinc is removed the exposed iron rusts. ‘* Moving parts on machines can be protectad by water repellent oil or a grease layer. 30 Gal rgnis reserves Natural Sciences 9 :‘When non-metals burn in excess oxygen, non-metal oxides are formed. Non-metal oxides tend to be acidic (low pH). The general equation for this reaction is: Non-metal + Oxygen -— Non-metal oxide = Reaction of Carbon (C) with Oxygen ‘When carbon (charcoal is mainly carbon) burns in oxygen it burns with a bright luminous yellow flame. ¥ carbon + oxygen — carbon dioxide Word equation c + 0, > CO, Balanced chemical equation Goal (carbon) burning in air (oxygen) Reaction of Sulfur (S) with Oxygen When sulfur burns in oxygen it burns with a blue flame. The product formed (sulfur dioxide) has a characteristic choking smell ‘Sulfur ’ ‘Sulfur burning sulfur + oxygen — sulfur dioxide wou equation S +0, > SO, Baloncod chemical equation Natural Sciences 9 * At rights reserved 31Some chemicals may be divided in two categories, acids and bases. Bases Properties Pr + Sour taste, + Feels rough. + Tums blue litmus red. + Has a pH value of <7 « Usually has hydrogen (H) in front ofits f chemical formula y Examples + Hydrochloric acid (HC!) * Sulphuric acid (H,SO,) - also known as battery acid. + Nitric acid (HNO,) += Acetic acid (vinegar) + Citric acid (in citrus fruits) Examples roperties + Bitter taste. + Feels smoothisoapy. + Tums red litmus blue. + Has a pH value of > 7 + May have hydroxide (OH) at the end of its chemical formula. + Sodium hydroxide (NaOH) - caustic soda (Grain cleaner) + Calelum hydroxide (Ca(OH),)- lime ‘+ Ammonium hydroxide (NH,OH) - kitchen leaner. ‘+ Sodium bicarbonate (Na,CO,) - bicarb. pH Scale Substancas with a pH <7 are acidic; substances with @ pH > The pH scale is a set of numbers rangiig from 0 to 14 that indicates how acidic or basic @ substance is. 7 are basic. Ifa substance in neither acidic nor basic then itis said to be neutral and has a pH of 7, e.g. pure water. The pH scale Indicators solution or test papers, A colour specific change occurs when indicators can also show the strength of an acid or base. Examples of indicators + Indicators in solution: universal solution, bromothymol blue, methyl orange, phenolphthalein. + Paper indicators: universal paper, red litmus, biue litmus. + Natural indicators: red cabbage juice, black tea, tumeric water, beetroot juice. ‘Acids tum indicator paper yellow, orange and red |- gases tum indicator paper blue and purple |« Neutral substances change the colour of incizator | paper to green. ©atrights reserved ft increasing strength of acid @ _ increasing strength of base 3 _lnrosig sven of bsg Lela o]s a FF 3 eS Soh, Indicators are used to test whether a substance is an acid, a base or neutral. Indicators may be in the form of ‘an indicator is added to an acid or base. Certain Universal indicator has the ability to show the full range of pH values by different colour changes. Paper strip indicators Natural Sciences,Neutralisation Reaction Noutraiisation occurs when an acid reacts with @ base and forms a solution that has a neutral pH (7). The H from the acid combines with the OH from the base to form water. Asaltis formed during this reaction. ‘The general equation is: y Acid + Base > Salt + Water {i ‘Example 1: i [HCl + NaOH — NaCl + HO | Earp 2 H,SO, + Mg(QH), MgSO, + 2H,O aso reacts wit an ald and makes itfose acidic oF neutral ei Jrecate ots base and makes Its base or neutral Uses of Neutralisation Reactions Soil treatment ‘Most plants grow best at pH 7. Ifthe soil is acidic or | | The stomach secretes hydrochloric acid which helps alkaline the plant growth can be severely affected. in the digestion of food. However too much acid in Farmers often add chemicals to the soil to change the stomach can lead fo indigestion, To neutralise its pH. excess acid, a base stich as sodium hydrogen carbonate (bicarbibaking soda), is mixed with water and taken. An indigestion tablet may also be taken. Ifthe soil is too acidic its treated with a base in ‘order to:neutralise it. Chemicals such as ime. (calgium oxide) or chalk (calcium carbonala) are used to neutralise acidic soil. Insect stings Waste from industries JAbee sting contains acid, Calamine lotion (zinc Many industries produce waste that is often acidic, carbonate) or baking soda is rubbed onto the bee This acidic waste can enter rivers, lakes and sting to neutralise the acid and relieve the painful estuaries killing aquatic organisms, Slaked lime symptoms of the sting. (calcium hydroxide) is often added to the acidic Wasp stings are alkaline, and an acid is used to waste to neutralise It. neutralise and treat the painful sting. Vinegar is orally uged to treat wasp stings, Natural Sciences 9 @©Atrights reserved 33Reaction of an Acid with a Metal Oxide When an acid reacts with a metal oxide the products are salt and water. The type of salt formed will depend on the acid and metal oxide used in that reaction. ‘The general equation is: ? Acid + Metaloxide — Salt + Water Example HCl + MgO -» MgCl + HO | Ficomnane aod Nopresum ove ‘Magnesium chioride water (ea) ACID RAIN When fuals such as coal, oil and petrol ere bumt, carbon dioxide, sulfur dioxide and various oxides of nitrogen bre released into the atmosphere. The main sources of these gases are vehicles and Industries such as power Stations. Sulurcioxide, carbon dioxide and the oxides of nitrogen mix with water inthe clouds and fall as acid rain. : Acid rain has severe effects on the environment. + Acid rain destroys trees and other plants. «= Buildings and monuments that are mace from limestone are severely damaged. = The acid rain makes lakes and rivers more acidic. This kills fish and other aquatic life, «Acid rain can also corrode cars, railroad tracks, airplanes and steel bridges. Sulphuric ais rie acta Formation of acid rain {Combustion gases issaive in rain walar to form ac rin) 34 Aiiighis reserves Natural Sciences 9Reaction of an Acid with a Metal Hydroxide ~ ‘An acid reacts with a metal hydroxide to form salt and water. The type of salt formed will depend on the type of acid and the metal oxide used in that reaction, The general equation is: ? Acid + Metal hydroxide—> Salt + Water Example Pee eee 1 a HCL_+ NaOH - NaCl + HO | Faraone acid Sedum aroide ab) Sa Reaction of an Acid with a Metal Carbonate ‘Metal carbonates are bases. When an acid reacts with a metal carbonate the products formed are salt, carbon dioxide and water. The effervescence one notices is the release of carbon dioxide. The general equation is: Acid + Metal carbonate + Salt + Carbon dioxide + Water Example 1: etigpresces (bubbles) HCl + CaCO, + CaCl, + CO, + HO |~ (catoum chide) Reaction of an Acid with a Metal ‘An acid will react with a metal to form salt and hydrogen gas, The general equation is: Acid + Metal — Salt + Hydrogen Example 1: 2HCl + MgO MgCl, + Ho |~ Titectons add tagraciom San Praca 0) magnesite) Example 2: penne 2HCI + Zn -> ZnCl, +(H,) Hyérochlode aca ine Sot Hycrogen (gos) ) tance) ¥ When hydrochloric acid is added to magnesium riobon in a test tube, bubbles of gas ‘re released. When a buming splinter is brought near the mouth of the test tube, the ‘gas ignites with a characteristic "bop" sound indicating thet the gas is hydrogen Natural Sciences 9 Oalighis reserved 35. aa Question 3 ¢ Questions eae Compete tho folowing general equations: pay 1. Meal + ongen > Provide tha coret term foreach ofthe flowing 2. Non-metal+ongen > 1. Tiny particles that makes up matter. 3. Ack + Basa > 2. Particles that occur within the nucleus. 4. Acid + Metal oxide — 3, Poatvely charged parle within an atom. 5. AGd + Metal hydroxide > 4 Aeubstanee composed of identical atoms 6. Acid + Meta carbonate. — (13) Cental coe ofthe atom, 8, Negatively charged particles within the atom. Question 4 7. Unenarged pares fourd win the nucleus Sty ewusion slow anton ano: ets 8. Vertical columns on the periodic table. — {Number that indeats te numbor of protons in an 2H, +0, 3 2H,0 tom 40. Horzontal rows onthe period tae 4. Name the reactants nine equation, ==) (10) | 2. Name te prodct inthe equation 2) 2. How meny atoms are thn: Question2 ayone maocale yategen Name each ofthe folowing elements tone molecule oxygen 2)ou two molocule water a) He Na Question 5 ac Balance the folowing equation: my Me ane al Fe +0, + Fe,0, 2. We don esol eahat te aowng ay era Complete and balance the lowing enustions: ‘b) Calcium faa Cade @) c) Potassium 2A +O, > (3) @)Litium : Question? umiium °) Alum ©) ‘Tabulate 4 differences between acids and bases. (5) 3. Define a compound. (| question 8 1 Defeoan indicator. @ 4. Pride cheicaliomice french tefsonng | 3) Guety eames aca efevng conpounis 2) pope ndcator @ arate e)househaldinceaor @ ne 3. Explain how: esr dot a) elgestion due lo excess stomach acid canbe arbon dioxide relieved (3) 6) sodium chloe b) eck sls canbe treated to make th soll more ‘lithium oxide ‘suitable for plant growth (B) 4) sodium heron 4. When sulphur loi gas mies wih water nan 1) iver nate dhe one acd ra 1) magnesium clo 2) Name TWO other gases that can also mix wth water })poteesium brome (10) tovorm aot ran ‘a by State THO waysn which acé rain afets 5. Name each of the following compounds; ‘ecosystems, @ a) Cuco, Question 9 1 b)ZnO 1. Write out the following equations in words: ©) NaHCO, a)HCI+ MgO > MgCl, + HO ® 3 Ga b)HCI+Zn > ZnCl, +H, (a) ) Nes 2. Wie he totoning equalon sy erm 9) CuSO, hydrochloric acid + calcium carbonate —> calcium h)HS (8) chloride + carbon dioxide + water (4) 36 @arrionsresenes Natural Sciences 9a Energy and Change ess Definition: A force is either a push ora pull. Forces act in pairs - when you push on an abject, you fee! it pushing back on you, Unit of Measurement: The strength of a force Is expressed in newtons, symbol N. named after one of the wor'd's most famous scientists, Sir Isaac Newton, The weight of an abject of mass 100 g is almost the same as a force of 1N. 1000 N = 1 KN (Kilonewton). The strength of a force is measured with a newton meter, which is similar to a spring balance. Weight of object in N= its mass in kg x 10 fa newtonmeter Effects of a Force é Tnerease he Speed ofa ©aAl rights reservedBalanced Forces Balanced forces occur when two forces acting on an object are equal in size but in opposite direction. If the forces are balanced then the object will not move or if the object that is already moving, it will continue to move at the same speed in the same direction. Balanced forces cancel each other. . Balanced force (no movement) Unbalanced Forces Forces that do not cancel each other are called unbalanced forces. Unbalanced forces can cause an abject to ‘move in the direction of the nat force or resultant force. Torilse wins by 40. ‘Box wil move in he draction in which Tortoise pushes, with resultant force of 40 N. The fect of unbalanced forces Types of Forces Forces can be placed into two groups: Contact forces: where contact must be made between objects for the force to take effect, €.. Tension = Compression + Torsion (twisting forces) + Shear forces + Bending forces ‘Friction (frictional force) Non-contact forces: where forces can act through empty space without objects touching each other, ©.9.: + gravitational force ‘= magnetic forces + electrostatic forces 338 ll ghts reserved Natural Sciences 9A. Contact Forces 4. Tension 2.Compression — ‘Tension is a pull force. Tensile forces tend to stretch an | [Compression is @ push force. object because they act away from a each other. Compressive forces tend to compress (squash, flatten} an object because they act towards each other. 3. Torsion ‘Torsion causes twisting of an object, ||Shear (or shearing) forces act at ght ||Bending forces are really two sels of ‘24g. unscrewing a bottie cap. There | Jangles to an abject with a tengency to || forces, one set of tensile force and are two forces, acting in opposite | Jout or slice an object. A pair ‘one set of compressive forces. The directions around a common centre. | |scissors or garden shaars tend to cut, || tensile forces tend to straich one side ‘since the forces exerted by the blades || of the object, while the compressive act at right anglos to the object. forces tend fo compress the opposite side. This results in the bending of the object. HY \ Frictional force is @ force that comes into existence wherever two surface=Tnagt and one surface sides or tends to slide over another surface. Frictional force always acts opposite to the direction af motion, The strength of frictional force is determined by the weight of an object and the roughness/smoothness of a surface. ‘An object will only move when the applied force Is greater than the fictional force. Reducing friction + have smooth’ or highly polished surfaces. + use a lubricant (e.g. oil) between the surfaces, even using a fine powder between surfaces, + reduce the weight of the moving object. Problems caused by friction ‘+ Causes wear and tear on the moving surfaces. = Wastes energy, + Builds up heat between the moving surfaces. + Slows down a moving object. (Air friction ‘causes drag on fast moving vehicles, ) Usefuiness of friction + Friction between our shoes and the floor prevents us from slipping and enables us to walk + Allow the sharpening of knives, polishing of surfeces and grasping of objects. + Friction between tyres and the road stops vehicles fram skidding + Friction between the brakes and the wheels enables vehicles to slow down or stop. Natural Sciences 9 39B, Non-contact Forces Non-contact forces produce their effect through space, without the objects touching each other. They are also called feld forces, 4. Gravitational Force Any two objects that have mass will exert an attractive force on each other. This force is called gravitational force. Gravitational force is a pull force. Gravitational attraction depends on: 4, mass of the attracting objects, 2, distance between the centres of the attracting objects. Earth-Moon gravitational attraction In the case of small objects, the gravitational force is so small that we ignore it. When one object is massive (having a large mass) 6.g. planets, then the gravitational force cannot be ignored. The gravitational force with Which the Earth attracts objects is called weight. If the Earth were larger, like Jupiter, weight would be very much greater. You would weigh 10 times more on Jupiter than on Earth. On the Moon you weigh 6 times less (and also jump 6 times higher) because the Moon is less massive than the Earth, The separating distance between objects is also important. Large separating distances mean very much smaller gravitational force; smaller separating distances results in a very much larger gravitational force. Neptune Gravitational forces keep the planets in orbit around the Sun 40 O©AIriahts reserved Natural Sciences 9Effect of gravitational force on falling objects Since gravitational force is a force, it has the effect of causing any falling object to build up speed. We have said that a force causes acceleralion. Gravitational force causes a falling object to increase its _ speed atithe rate of 10 mis every second. The longer the object remains falling..the greater will be ifs final speed when it stikes the ‘ground. We say that a falling object accelerates at 10 mis ever ‘secofid. This special acceleration due to gravitational altraction is, called gravitational acceleration or gravity (symbol g). ‘he bal alowed to fal from rat, Gallo peered ti famous experiment at tha lop ofthe Leaning Tower Ps domenstrating that al objects faa the some 1 second ister has Tale, iespoctve of ele mace. a speed of 10ns, — Teaning Tower of Pisa (Galilelo inset) Gravitational force in space ‘The gravitational force that exists between the earth and the Moon, keeps the Moon in obit around the Earth. In addition, the pull between the Earth and the Moon causes tides, by the Moon exerting a pulling force on the oceans. The sun, Earth and all the other planets are attracted to each other by gravitational forces. These forces keep the planets moving around the sun in very predictable patterns. Gravitational force is also responsible for the satellites remaining in orbit above the surface of the earth. The relationship between Mass and Weight ‘Weight is the force (of gravity) with which the Earth attracts (pulls down on) an abject. Very simply, itis the heaviness of an object. The weight of an object is proportional to its mass: the greater the mass, the greater its ‘weight. Mathematically, the relationship is represented by the equation: ess in kg Weight in newtons (N) +f ‘Seno lp the mats by 10 and giv he sneer = PW = ma] smenurcsncweies, W =r Suet on Scene ere value of gravity (10) Example: | | Calculate the weight of a person who has @ mass of 120kg: a) on Earth b) on the Moon where the gravitational acceleration (q) is 1.6 8) Wea = 79 | i Natural Sciences 9 ©Arrights reserved Als 2, Magnetic Forces. A magnet is made up of materials such as rm (F repel other magnets. if a magnet is suspend at ité centre by a thin thread) will eventually settle such that it aligns itself along the Earth's N-S magnetic poles (The Earth has a magnetic core.) The pole of the magnet that points North is called the north pole (N) and if usually coloured red for identification. The south pole of the magnet (S) is coloured blue. This characteristic of magnets was first used by early navigators, and is still used In compasses today. mM iN | Different kinds of magnets steel, nickel (Ni) and cobalt (Co). Magnets can attract or Attraction and repulsion in magnets works on a simple rule (law) Like poles repel each other; unlike poles attract each other. ——a. — Ca Atracton Reputsion Magnetic eld ‘The region around a magnet where the influence of a magnetic can be felt is called a magnetic field. Iron filings sprinkled near a magnet show the magnetic field pattern of the magnet. Scientists have developed the idea of field lines to help visualise a magnotic field. Field lines have the following characteristics: ; + They are imaginary and do not exist in realty. | + Fleld lines run ftom north to south. | + Ahiigh concentration of feld fines indicates a strong magnetic field. + Field lines do not cross each other. aie fleld pattern of a bar magnet ‘Magnetic fleld lines of a cehbariciat | Hl 42 @Arights reserved Natural Sciences 9 | iUses of magnets 4, Computers and Electronics Hard drives in computers contain magnetic material for data storage. Magnets are found inside the speakers attached to computers, televisions and radios, Speakers Industry ; Elecitic generators in power stations rely on magnets to convert mechanical energy into electricity. Electric motors use magnets to bring about rotation. Magley trains do not have any wheels but operate by using two opposing magnets that cause the train 0 float above the rail making it extremely fast. [Mag = magnetic; Lev = levitation (feating)} Electromagnets in cranes attract and move large amounts of metal. 2, 3. Health and Medicine Magnets are found in certain medical equipment such as X-rays and MRI (Magnetic Resonance Imaging) machines. MRI chines pass a magnetic field over the human bady creating a picture" or image of all the body tissues, enabling any A patient about to undergo a MRI scan 4, Home Refrigerator magnets (fridge magnets) hold paper and other emall items to the refrigerator. Credit and debit cards make use of magnetic strips that contain financial information. ‘Magnets are found in phones, door bells and children’s toys. ‘Magnetic strips are used on cupboard and fridge doors to keep them shut. Natural Sciences 9 QAI his sewed 433, Electrostatic Forces ‘An electrostatic force is @ non-contact force exerted by charged objects. The force can either be attractive or repulsive. Anneutral or uncharged object has an equal number of positive (protons) and negative charges (electrons). IF the number of negative charges is increased {by adding electrons), the object acquires an overall negative charge; if the negative charges are decreased (by removing electrons), the object becomes positively charged. Note that only electrons can be transferred between objects. Protons do not move. Electrostatic attraction and repulsion work on a simple rule (law): Like charges repel each other; unlike charges attract each other. -@Qe- Attraction Repulsion Detecting charged objects S> An electroscope is used to detect the presence of a charged object. The leaves ‘on an electrascope move apart (repel) when a charged object is brought close to ‘or touches the disc. ‘An electroscope Charging objects by friction Electrons can be adied to objects or removed from objects by friction, i.e. rubbing on or rubbing off electrons. ‘Objects charged by friction become positively or negatively charged, depending on the material that makes up the object. Plastic objects e.g. PVC. take on a negative charge, and glass objects take on a positive charge. Charging a PVC rod by friction = Charging a glass rod by friction ‘A PVG rod rubbed with a doth takes on a negative ‘Aglass rod rubbed with a cloth takes on @ positive ‘charge because electrons are rubbed off the cloth charge because electrons are rubbed off the glass ‘ante the PVC rod, +06, onto the cloth, Bofore rubbing Botore rubbing Each lem has en equal number of + ne Each tom has an equal number of + and — charges, Le. they are uncharged. ‘charges, i. thay are uncharged. ‘After rubbing Aftor rubbing Electrons are rubbed of the clolh onto the rod, Electrans ate rubbed off the rod onto the elt, making ‘making the rod negatively charged, because I the od posttvaly charged, because It now has gs — ‘ow has more — charges. charges. we we 44 @aliihis reserved Natural Sciences 9Lightning Lightning is a giant electric spark. Lightning occurs when excess electrons from a cloud are discharged and reach the earth, During this discharge, a massive ‘amount of energy in the form of heat and light is released, and is seen as the lightning bolt. The heat released causes a sudden expansion of the air around ning bolt, which becomes @ sound wave. We hear this sound wave as thunder. Water droplets in clouds become charged by the air rubbing against them. The ground (earth) becomes charged by wind (friction). A very strong attractive force exists between the negatively charged cloud and the positively charged earth. When the altractive force becomes strong enough,.electrons from the cloud jump through the air to the ground, causing the lightning bolt, Lightning tends to strike the tallest point. Tall buildings and thatched houses usually have lightning conductors which, ifstruck, conduct the electricity safely to the ground, without causing damage. Forked lightning Safety precautions during a thunder and lightning storm Lightning often precedes rain, so if you hear the sound of thunder, seek shelter. In the event of a lightning strike, the safest place to be is in a structure that forms a shell, e.g. car (best, but nothing to do with the rubber tyres) or inside a house. Other precautions to take in a lightning storm: + Stay away rom trees. Crouch down in the open, or in a hollow area, put your feet together and place your hands over your ears to minimise hearing damage from thunder. + Avoid any contact with water. Water is a conductor of electricity, so do not take a shower, wash your hands or wash dishes. + Swimming, snorkelling and scuba diving are not safe. + Stay away from fences and metal objects. + Do not use a corded telephone. Lightning may strike external phone + Switch off electric equipment like computers and television sets. + Stay away from windows and open doors. Static Electricity (Static) You may have noticed one or more of the following, especially during winter: + You get a shock when you touch @ door handle. + Sparks can be seen when you comb dry hair in total darkness in front of a mirror. You may also hear crackling sounds. + When you take off your jersey in total darkness and squash it in your hands you notice sperks and hear crackling sounds. ‘+ Aballoon, plastic sheets or small pieces of paper cling to you: Each of the above is lightning on a very small scale. You and the object (door handle, comb or jersey) have become charged. When you touch the door handle excess electrons jump across, in the form of a tiny electrical sparks. Lightning is a giant electrical spark. balloon, plastic sheets or small pieces of paper cling to you because they or you are charged and electrostatic attraction ‘causes them to cling to you. Moisture in the air discharges charged objects, making them neutral, so the effect is not noticeable in humid weather, Charged balloon attracting hair Natural Sciences 9 ©Al rights reserved 45Electricity is regarded as the greatest modem invention (the wheel being the world's greatest invention), Electric Cells A call is a device in which chemical reactions takes place resulting in the production of high energy electrons (charge). Cells convert chemical potential energy into electrical energy. Anumber of cells connected together is called a battery. A | cell has 2 positive terminal and a negative terminal. | i SEE lGcH Symbot for a cell celts A battery (of cals) ; Electric Current i! Curcentis the flow of charge (electrons) through a conductor. Current ows | Symiboit from the postive termina, fnrough the circu, ack tothe negative terminal. | Unit: ampere (A) with an ammeter: The symbol for current is | ori and the SI unit is ampere (A), | Gicut diagram symbol: 1 i ‘Curent strength is expressed in amperes, abbreviated to amps, and measured ingrument: ammeter | leaves a cell with high energy, loses its energy to a component (e.g. a light bulb), and retums with lower energy. e.g. = 5A. An amimeteris always connected in series Current is never lost in @ circuit: if 5A of current leaves a cel, then SA of current i) will return to the cell. ie __.Connectadin series b C i i / ‘ be ‘ { Simple circuit with an ammeter in series a ' i Voltage if Voltage is the energy cartied by the charges in an electric current. Alow vollage [Saou y } call, e.g. a penlight battery, produces a current in which the charges carry little eee | energy (1.5V); household electric current carries 220V. Voltage is often called ‘Unit: Volt (V) : ( potential difference. The symbol for voltage is V and the SI unit is volt (V). Instrument: Voltmeter | A voltmeter is usad to measure the energy of 2 current. Itis always connected | Cut dlagram sympe\ | in parallel with another component, e.g. a light bulb, leat i ‘Acomponent/appliance uses the energy that an electric current carries. Current |__inparale 1 w Hl ‘Avoltmeter ‘Simple circult with a voltmeter in parallel Hl 46 Av rams reserved Natural Sciences 9