MRSGREN

1. Movement
2. Respiration
3. Sensitivity
4. Growth
5. Reproduction
6. Excretion
7. Nutrition

animal cell

plant cell

Nucleus
Control center of the cell

Cytoplasm
A jellylike fluid inside the cell in which the organelles are protected
Organelle
A tiny cell structure that carries out a specific function within the cell

Vacuole
Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

Mitochondria
An organelle found in large numbers in most cells, in which the biochemical
processes of respiration and energy production occur. (Acts as the powerhouse of
the cell)

Chloroplast
organelle found in cells of plants and some other organisms that captures the energy
from sunlight and converts it into chemical energy

Cell wall
strong, supporting layer around the cell membrane in plant cells

Golgi apparatus
A system of membranes that modifies and packages proteins for export by the cell

Cell membrane
A cell structure that controls which substances can enter or leave the cell.

Endoplasmic Reticulum
A system of membranes that is found in a cell's cytoplasm and that assists in the
production, processing, and transport of proteins and in the production of lipids.

Ribosomes
organelle that makes proteins

Lysosomes
An organelle containing digestive enzymes

Magnification formula
Image size/real size
Cilia
Hairlike projections that extend from the plasma membrane and are used for
locomotion

Root hair cell

Absorbs water and mineral ions from the soil due to its big surface area. They also
have a large amount of Mitochondria

root hair cell (label)

They lack chloroplast. Can't photosynthesize under the ground.

how do water get from the root to the leaf of the plant for photosynthesis to happen?
root hair cell => root cortex cell => xylem => mesophyll cells.
The upper epidermis
Transparent so light can pass through it to reach the palisade layer for
photosynthesis. It has no chloroplast.

red blood cells

Blood cells that carry oxygen from the lungs to the body cells. Does not have a
nucleus.

sperm cell
Acts as Reproductive cell

Osmosis
Diffusion of water through the cell membrane

Hypotonic Osmosis
Water concentration is greater on the outside of the cell than on the inside of the cell
Water will move IN THE CELL
Cell to swell and become swollen cell (turgid)

Isotonic osmosis
no movement of water

Hypertonic Osmosis
Water concentration is greater on the inside of the cell then on the outside of the cell
Water will move OUT OF THE CELL
Cell to shrink and shrivel

Enzymes
proteins that act as biological catalysts

substrate molecule
substrate molecules are the chemicals that an enzyme acts on

Active site of an enzyme

the region of an enzyme that attaches to a substrate

Amylase
Enzyme in saliva that breaks the chemical bonds in starches
Product of amylase and starch
glucose
Protease
enzyme that digests protein
Product of protease and protein
amino acids
Lipase
pancreatic enzyme necessary to digest fats
Product of lipids and lipase
Fatty acids and glycerol
Due to high temperature and PH (acidic), enzyme will get ____
denatured
Denatured
Change the shape of an enzyme so that it can no longer fit the substrate => stop
working
When you describe a graph of enzyme
1. Be Specific (From what degree to what degree)
2. Random collision (more energy due to high temperature)
3. Optimum temperature (reaches the peak)
4. Denature (excess vibration causes change in shape)
5. enzyme won't fit anymore ( due to lock and key theory)
6. The rate of reaction drops rapidly

Photosynthesis
Conversion of light energy from the sun into chemical energy.

Photosynthesis equation
6CO2 + 6H2O ------> C6H12O6 + 6O2
Plant converts glucose into ___
starch for storage, cellulose for cell wall and other substances need by the plant.

Starch test using iodine

The Iodine Test for Starch is used to determine the presence of starch in biological
materials.

Blue/Black - starch is presented

Brown/Red - starch is not presented

- heated in boiling water (soften cell wall so that iodine can enters)
- heated in alcohol (removes chlorophyll)
- drops iodine solution
The rate of photosynthesis is affected by
Intensity of light, concentration of carbon dioxide and temperature
Rate of photosynthesis graph (light intensity)
Light intensity

Can't go up due to limiting factor (temperature or CO2)

Rate of photosynthesis graph (CO2 concentration)

The concentration of Carbon Dioxide

Can't go up due to limiting factor (temperature or light intensity)

Rate of photosynthesis graph (temperature)

Temperature

when reaches its optimum temperature (25 degree Celsius), enzymes start to
denature. Completely denatured at (45 degree Celsius)

The leaf structure

waxy cuticle
Forms a waterproof layer to stop water loss due to photosynthesis

upper epidermis (leaf structure description)

protective layer which is transparent so lights can pass through
palisade mesophyll
Layer of tall, column-shaped mesophyll cells that packed with chlorophyll to
maximize photosynthesis

spongy mesophyll
Loose tissue beneath the palisade layer of a leaf; has many air spaces between its
cells

Air spaces in spongy mesophyll

To allow CO2 and O2 to diffuse to and from all cells

lower epidermis
protective layer on the bottom of leaf which contains stomata & guard cells
stomata (stoma)
Small openings on the underside of a leaf through which oxygen and carbon dioxide
can move

guard cells
control the opening and closing of stomata

Xylem
vascular tissue that carries water upward from the roots to every part of a plant

Phloem
Living vascular tissue that carries sugar and organic substances throughout a plant
(food)

Transpiration movement
evaporation of water at the surfaces of the mesophyll cells followed by loss of water
vapor from plant leaves, through the stomata.
The rate of transpiration and temperature
High temperature = more energy for the molecule

the rate of transpiration and humidity

Because water has to diffuse its H2) concentration

Translocation movement
movement of food through the plant

How does plant get Carbon Dioxide?

Carbon dioxide enters the plant through the stomata.

How does a plant get water?

from the roots
Test for reducing sugars
Benedict's test

-Positive: green > yellow > orange > brick red precipitate
-Negative: no change (blue)

- First you take your Benedict's reagent

- You add drop-wise to each sample
- Label each sample for this test
- Add boiled water into a beaker and place all the sample into the water bath

Test for protein

Biuret solution

-Positive: Purple
-Negative: No change (blue)
- First, add dropwise of the biuret solution to each sample
- Observe if the color changes to a purplish violet then protein is present.
Test for fat
Ethanol

-Positive: Milk white emulsion

-Negative: No change (colorless)

- Measure 2cm3 of ethanol

- Pour in each sample
- Shake it vigorously
- Add 2cm3 of distilled water
- Observe
Balance diet includes
1. Carbohydrates
2. Proteins
3. Lipids
4. Vitamin
5. Minerals
6. Fibre
7. Water

Carbohydrates function
Broken down to glucose to provide energy.
Good sources of carbohydrates
Grains or Starchy food

Proteins function
build muscle, skin, hair; grow and repair tissue in body.
Good sources of protein
meats, poultry, fish, cereals, beans, nuts, and seeds.

Lipids function
long term energy storage, insulation (keeping warm) and making cell membrane
Good sources of lipids
Milk, Fat or Dairy

Vitamins function
catalyst in biochemical reactions
needed in small amounts
Good sources of vitamin
Vitamin C - fruits
Vitamin D - Fish
Minerals function
regulate body processes (produce red blood cell)
Good sources of minerals
Fruit and vegetable
Fibre function
Regulate the functioning of the digestive system
Good sources of fibre
- wholegrain rice
- wholemeal, granary or seeded bread
- wholemeal pasta
- dried fruits
- nuts, beans and lentils

Water
a solvent, transport substances and maintain temperature.

anabolic reactions
building up muscle

catabolic reactions
breakdown of molecules
malnutrition
lack of proper nutrition
deficiency
lack of something
Vitamin C function
An important substance needed for proper repair of the skin and tissues
Vitamin C deficiency
Scurvy (bleeding gums)
Vitamin C sources
citrus fruits
Vitamin D function
calcium absorption and bone formation
Vitamin D deficiency
Rickets and bone pain
Vitamin D sources
sunlight, egg yolk, fortified milk
Calcium functions
Blood clotting, cardiac function, nerve transmission, smooth muscle contractility
Lack of calcium
Rickets
Iron function
Helps carry oxygen to the blood and helps cells use oxygen.
lack of iron
anemia - become tired and weak
mechanical digestion
Part of digestion that uses movement and muscles to break down food

chemical digestion
Process by which enzymes break down food into small molecules that the body can
use
digestion
break down of
large, insoluble food molecules into small,
water-soluble molecules using mechanical
and chemical processes.
Absorption
movement of digested
food molecules through the wall of the
intestine into the blood.
Egestion
The removal of nonsoluble waste materials.

Where does digestion occur?

Mechanical digestion
1. chewing in mouth

Chemical digestion
1. Saliva in mouth
2. Acid and pepsin in stomach
3. Enzymes in small intestine

Where does absorption occur?

nutrients and water are taken up by the blood system in the small intestine

Water in large intestine

Where does egestion occur?

faeces formed in the large intestine

remove at anus
alimentary canal
digestive tube that extends from the mouth to the anus

stomach => small intestine (starch/protein)

Small intestine (fat)

Where does digestion begin?
starvation
suffering from extreme hunger
Constipation
lack of fiber which gives bulk to your faeces
obesity
having an excess amount of body fat
circulatory system
(aka cardiovascular system) This system works as the transportation highway for the
body. It consists of the heart, blood, and blood vessels. It transports substances
such as oxygen, carbon dioxide, and nutrients in the body.

a system of tubes with a pump and valves to ensure one-way flow of blood.

function of red blood cells

transport oxygen and carbon dioxide (have no nucleus)

Function of white blood cells

protect body from infection; regulates the function of other immune cells
function of platelets
blood clotting

Function of plasma
transport of blood cells, ions, soluble nutrients, hormones and carbon dioxide.

Double circulation
The body contains a double circulatory system
-One system pumps blood to the lungs where it becomes oxygenated
-Oxygenated blood enters the second circuit where it is pumped to the rest of the
body

(When blood is transported from the heart to the lungs, the pressure is smaller
compared to when it travels to the rest of the body)

What is in blood?
55% - plasma
<1% - buffy Coat
45% - erythrocytes
Structure of heart
has four chambers (right and left atriums, right and left ventricles)

muscular wall of the heart

A strong _________ separates the left side of the heart from the right side of the
heart.

septum of the heart

separates Left & Right sides of the heart

atria of the heart

Are located superiorly and are the receiving chambers of the heart

Ventricles of the heart

Ventricles are the discharging chambers of the heart

The right ventricle pumps blood into the pulmonary trunk

The left ventricle pumps blood into the aorta
Valves of the heart
tricuspid, pulmonary, mitral, aortic

heart diagram
Left ventricle and left atrium are oxygen rich blood and right ventricle and right atrium
and ventricle have oxygen poor blood

arteries
Blood vessels that carry blood away from the heart

Bright red blood color

Have thick walls to go against the pressure of the blood

Veins
Blood vessels that carry blood back to the heart

Purple blood color

much thinner wall because of less pressure

Capillaries
Smallest blood vessels linking arteries and veins

Thin wall which allows diffusion of substances in and out of the blood

How does blood move through heart?

De-oxygenated blood moves from vena Cava => right atrium -> right ventricle ->
pulmonary arteries -> lungs to be oxygenated

Oxygenated blood then back to the pulmonary vein -> left atrium -> left ventricle ->
aorta (main artery)

How does blood move through blood vessel?

(From the heart)
artery => arteriole => capillary => venule => vein
Which side of the heart has oxygenated blood?
left - oxygenated
right - de-oxygenated

Diastole
Atria filled with blood. Chamber filled with blood.
Systole
Contraction of the heart. Blood pump into circular
Atrial Systole
Atria contraction. ventricles filled with blood

ventricular systole
Ventricle contraction. atria filled with blood

coronary heart disease

the blockage of coronary arteries (blood clotting) due to the building of plaque (made
of cholesterol, fatty substances, cellular waste products, calcium and fibrin.)

it's reducing the flow of oxygen-rich blood to the heart muscles. Sometimes, this
plaque might rupture (break apart), causing the formation of blood clots or the
broken piece of plaque to travel down to a narrow arteriole and block it up. Both of
these completely cut off the supply of oxygen to the heart muscles. This could cause
heart failure.

It can be caused by a diet high in fat, especially saturated fats, it can be caused by
stress, smoking, age, and sometimes it is genetically based.
Physical activity on heart rate
After exercise, we increase our heart rate

The more fit and healthy a person is, the faster their resting heart rate will be
Why does fit person tend to have a shorter recovery time?
They are able to more efficiently provide glucose and oxygen, and carry carbon
dioxide away. Their heart is stronger and they have a more efficient circulatory
system; their muscles are also more used to physical activity.

Once the exercise has finished, both people go into recovery. This is when the blood
keeps supplying oxygen to muscles, and replace missing glucose.
what are the important processes of transporting fluid into and out of the capillary?
Filtration and Reabsorption are the movements of fluid in and out the vessels.

Filtration - water is forces out of the capillaries carrying nutrients.

Reabsorption - waste and water is drawn into the capillaries.

what caused filtration (transporting fluid)?
caused by BHP - blood hydro-static pressure
(blood being forces against the walls of the capillaries)
what caused reabsorption (transporting fluid)?
caused by osmosis as water diffuses from the
interstitial fluid carrying waste back into the
capillaries = BCOP

(blood colloidal osmotic pressure) generated by the non-diffusable plasma protein

How does our blood defend us from disease?
By using 2 types of white blood cell.
- Phagocytes
- Lymphocytes
Phagocytes
A white blood cell that defends us from disease by ingesting bacteria "Phagocytosis"
- cell eating.

Due to its adaptation (flexible shape), they can squeeze out of capillaries to sites of
infection
Lymphocytes
A type of white blood cell that make antibodies to fight off infections and bacteria.
The movement of fluid through capillary.
1. Blood enters capillary beds under high pressure.

2. Plasma carrying dissolved nutrients is forced out of capillaries by the process of

filtration.

3. Plasma is now called tissue fluid.

4. Tissue fluid carrying waste materials is re-absorbed via osmosis.

5. Blood leaves capillary beds under low pressure.

lymph
the watery fluid in the lymph vessels collected from the tissue spaces

lympathic system
extension of the circulatory system fights invaders and infections by passing white
blood cell through the lymph.

respiratory system
A system of organs, functioning in the process of gas exchange between the body
and the environment, consisting especially of the nose, nasal passages,
nasopharynx, larynx, trachea, bronchi, and lungs.

Larynx
the hollow muscular organ forming an air passage to the lungs and holding the vocal
cords in humans and other mammals; the voice box.
Trachea
A tube which allows air to pass to and from lungs

Lungs
two spongy organs which are responsible for respiration
intercostal muscles
Muscles which move the rib cage during breathing
Ribs
The bones in the chest that protect the heart and lungs.

Diaphragm
Large, flat muscle at the bottom of the chest cavity that helps with breathing

bronchus
one of the two tubes that connect the lungs with the trachea

Bronchioles
smallest branches of the bronchi

Alveoli
tiny sacs of lung tissue specialized for the movement of gases to the capillary
Thorax (respiration)
Inhalation: As lungs expand, air moves in. Diaphragm moves downward, rib cage
moves up and out

Exhalation: As lungs contract, air moves out. Diaphragm moves upward, rib cage
moves down and in

Gax exchange
Diffusion of gases (Oxygen and Carbon Dioxide)
gas exchange in alveoli
As we inhale, oxygen diffuses from alveoli into blood, carbon dioxide diffuses into the
alveoli and moves out as we exhale.

Gas exchange in tissue

-O2 moves from blood to tissue
-CO2 moves from tissue to blood

Inspired air
Air we breathe in. Contains about 21% O2 and 0.04% CO2
What is the difference between inspired air and expired air?
Nitrogen stays the same => we do not use nitrogen

Water vapour:
Inhale: some
Exhale: more

Explanation for the difference between inspired air and expired air.
Oxygen decreases as it is used up during respiration (reactant)

Carbon dioxide increases as it is made during respiration (waste product)

Water vapour increases as it is a waste product of respiration

Nitrogen remains the same as we do not use it in our bodies (it is inert)
Test for inspired air and expired air.
Use lime water. The milkier limewater has more carbon dioxide.
How does physical activity affect rate and depth of breathing?
During exercise, the volume inhaled (depth) increases, also as the breathing rate.
Breathing rate and depth increase to absorb more oxygen for the muscles as
exercising muscles need to respire more to get more energy.
2 specialized cell lining the respiratory tract.
goblet cell, ciliated cell
goblet cells
a cell found in the respiratory and intestinal tracts, which produce mucus (a slimy
substance) to trap dirt and bacteria.

ciliated cells
Ciliated cells have tiny, microscopic hair on them called cilia; The cilia beat in unison,
and sweep the mucus upwards, towards the back of the throat.

Why is smoking bad for gas exchange?

Carbon Monoxide: A poisonous gas; combines with hemoglobin, preventing them
from transporting oxygen
Nicotine: Addictive; increases heart rate & blood pressure

Tar: A carcinogen (a substance capable of causing cancer in living tissue) -

increases the risk of lung cancer; lines the air passages, increasing mucus
production and paralyzing and damaging cilia, causing bronchitis.
Respiration
the chemical reactions that break down nutrient molecules in living cells to release
energy. It is not breathing
Two types of respiration
aerobic and anaerobic
aerobic respiration
Respiration that requires oxygen to break down nutrient molecules.

anaerobic respiration
release a smaller amount of energy in cells by the breakdown of food substances in
the absence of oxygen.

Respiration formula (aerobic)

C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy

glucose + oxygen --> carbon dioxide + water

Respiration formula (anaerobic)

In yeast:
glucose --> alcohol + carbon dioxide
C6H12O6 --> 2C6H5OH + 2CO2

In human:
glucose - lactic acid
Hormone
a chemical substance which is produced by an endocrine gland that is carried in the
blood to a target tissue (alerts its activity and is then destroyed by the liver).
Adrenaline
a hormone secreted by the adrenal glands, especially in conditions of stress,supplied
with lots of glucose and oxygen.

These are then used to make energy either to face up to the stress (fight) or to run
away from the stress (flight)

This is called the 'fight or flight' mechanism.

Effects of adrenaline
breathing becomes quicker and deeper
glucose is released from the liver
extra oxygen is used to make energy from the glucose in the muscles
heart beats faster
blood is directed from the skin to muscles
the body begins to sweat

Tropism
A directional growth movement made by a part of a stationary plant in response to
unilateral stimulus.
Phototropism
The growth of a plant shoot toward or away from light.

towards the light = positive phototropism

away the light = negative phototropism
(opposite with the stem)

Gravitropism/Geotropism
response of a plant to the force of gravity

towards the gravity = positive geotropism

away the gravity = negative geotropism
(opposite with the stem)

Auxin
Is the most common plant hormone. It is produced by root tip and shoots tip. It
affects the growing region of the tip

Auxins have a positive effect on shoots (make them grow faster) but a negative
effect on roots (slow down their growth)

Phototropism to shoot
Auxin made by shoot tip. Auxin diffuses down shady side of shoot due to the
presence of unilateral light. Auxin makes the root bends towards light, since high
auxin concentration stimulates growth in shoot.
Gravitropism in shoots
The root tip produces auxins which diffuse to the lower side due to gravity. High
auxin concentration inhibits growth in the root. The lower side grows slower than the
upper side. The root bends downwards

Experiment to show the effect of gravity on roots

shoot goes against gravity
root goes towards gravity
What causes tropism?
The tip is the place responsible for bending, since it produced a diffusible chemical
which stimulates growth.

asexual reproduction
A reproductive process that involves only one parent and produces offspring that are
genetically identical to the parent.

sexual reproduction
A reproductive process that involves two parents that combine their genetic material
to produce a new organism, which differs from both parents.
flower diagram
label the parts of the flower

carpel/pistil
Female part of the flower

Ovary
A flower structure that encloses and protects ovules and seeds as they develop.

ovule
female reproductive structure of a seed plant where the egg develops

style
hold up a flower's carpel, with the ovary at the base and the stigma at the top.
stigma
The tip of the female reproductive structure of a flower where the pollen lands

Stamen
Male part of the flower

Anther
produces pollen (sperm)

filament
Holds up the anther

sepals
protect the flower
Petals
modified leaves which are usually bright in color to attract pollinators.

Pollination
the transfer of pollengrains from the male part of the plant (anther or stamen) to the
female part of the plant (stigma).

Insect pollinated flowers (Features)

Attract Pollinators:
-brightly colored petals
-food reward - pollen and/or nectar, fragrance -
-scented - the smell to attract insect
-anthers and stigma lay inside the flower (firmly)

Wind pollinated flowers (Features)

Usually, lack colors and odors since they don't need to attract organisms.
- anthers and stigma lay outside the flower (loose)
Insect pollinated flowers (pollen collected)
sticky pollen - stays in contact with anther until insect arrives (so that it sticks to the
insect's body)

Wind pollinated flowers (pollen collected)

pendulous stamens (dangling around so that wind will carry the pollen away)

feathery stigma (large surface area)

Insect pollinated flowers (pollen quantity)
Smaller amounts (relatively large)
Wind pollinated flowers (pollen quantity)
Pollen: a small and light grains but a large amount (so that wind can carries)
cross-pollination
a reproductive process in which pollen from one plant is transferred to the stigma of
another plant

self-pollination
the transfer of pollen grains from an anther to the stigma of the same flower or to the
stigma of another flower on the same plant

Germination
Sprouting of a seed, and beginning of plant growth.

Germination Requirements
1. The seed needs the correct temperature (room temperature - 23 degree Celcius)
2. water
3. oxygen to germinate.

male reproductive system

produces and delivers sperm

Testicles (testes)
produce sperm and testosterone
Scrotum
sac that regulates the temperature of the testes
Sperm duct
Carries sperm from testes to urethra

prostate gland
A gland in males that contributes to the seminal fluid.
Urethra
tube that carries urine from the bladder to the outside of the body
female reproductive system
produces eggs for reproduction and provides place for growing baby.
ovary (reproductive system)
release female gametes
oviduct
Fallopian tube; tube that carries eggs from an ovary to the uterus
uterus
Female organ of reproduction used to house the developing fetus.
Cervix
The opening to the uterus
Vagina
Female organ of intercourse; birth canal
menstruation (period)
monthly shedding of the uterine lining

ovulation
process in which an egg is released from the ovary

Fertilization
The fusion of a female gamete (egg) and a male gamete (sperm cell)

sperm and egg comparison (size)

sperm cell is smaller compared to an egg
sperm and egg comparison (quantity)
sperm cell has a large amount compared to egg cells
sperm and egg comparison (mobility)
the sperm tries to move to the egg while it does not move.
How much chromosomes do humans have?
46 chromosomes in total

23 chromosomes from the sperm cell

23 chromosomes from the egg.
menstrual cycle
Cycle during which an egg develops and is released from an ovary and the uterus is
prepared to receive a fertilized egg.

approximately at day 14.

Zygote
fertilized egg

embryo
the developing human organism from about 2 weeks after fertilization through the
second month
immune system
a complex response system that protects the body from bacteria, viruses, and other
foreign substances.
HIV
the virus that causes AIDS (human immunodeficiency virus). It attacks certain types
of lymphocytes (white blood cell that produces antibodies) and the immune system,
makes it weakened and vulnerable to infection.
AIDS (acquired immune deficiency syndrome)
sexually transmitted infection caused by HIV, resulting in damage to the immune
system

Transmission of HIV
Sexual contact, shared needles, contact with blood, mother to baby

food chain
series of steps in an ecosystem in which organisms transfer energy by eating and
being eaten

food web
a system of food chains.

Herbivore
A consumer that eats only plants.
Carnivore
A consumer that eats only animals.
Omnivore
An animal that eats both plants and animals
Comsumer
an organism that obtains food by eating other organisms
Producer
An organism that can make its own food (plant)
Decomposer
An organism that breaks down wastes and dead organisms
Scavengers
an organism that feeds on the dead bodies of other organisms.
trophic level
Each step in a food chain or food web
How is energy transferred between trophic level?
the amount of energy decreases as the trophic level rise. (energy loss)
Energy loss (between trophic levels)
only around 10% of the energy is passed on to the next trophic level. Others passed
out through:

* heat energy
* life energy
* remains are passed to decomposers
why food chains usually have fewer than five trophic levels.?
because of the energy loss between each trophic energy.
carbon cycle
Carbon is dissolved into and evaporated from large water bodies, mainly in the form
of CO2

Plants take carbon dioxide out of the air through photosynthesis and convert it into
organic materials (remember the equation!)

Herbivores eat plants, containing carbon compounds in the process. Carnivores gain
carbon compounds by eating other animals

Animals and plants release carbon back into the air (in the form of CO2) through
respiration (remember the equation

When organisms die, they usually decompose. Decomposers break down the
organic molecules through the process of respiration to gain energy, releasing
carbon back into the atmosphere

If a dead organism does not decompose, the carbon is trapped in its body. It
becomes a fossil fuel over time

Combustion of fossil fuels releases carbon dioxide back into the air

What happens when we have greenhouse gases in excess?

The excess of greenhouse gases is called the enhanced greenhouse effect

When burning fossil fuels, the carbon in the fuels combine with the oxygen in the air
to form carbon dioxide. This process is called combustion. This increases the carbon
dioxide levels in the atmosphere

Cutting down trees reduces the amount of photosynthesis taking place, so less CO2
is being taken out of the air and used in photosynthesis and the oxygen product is
reduced. This means CO2 levels rise and O2 levels fall.

Undesirable effects of deforestation

Habitat destruction

Extinction

Loss of soil

Flooding

Increased carbon dioxide in the atmosphere

Species extinction through habitat loss: Deforestation
the destruction of habitats and/ or food sources for animals can result in their
extinction. It should also be noted that the destruction of forest habitats also reduces
the diversity of plants and animals, thus disrupting several food chains.
Soil erosion: Deforestation
Fewer trees and flora, in general, mean that there are fewer roots to hold the soil.
This means that each time it rains, a thin layer of soil is washed away. This causes
soil erosion and leaching of minerals (leaching is when a soluble chemical or mineral
is washed away from the soil by rainwater). The eventual result is that the land
becomes a desert.

Flooding: Deforestation
soil erosion is washed into rivers, causing them to fill up or become blocked. This
causes flooding. The loss of flora also means that there are no plant roots to take up
rainwater, which means more rainwater washes into nearby streams and rivers. This
makes flooding easier.

Carbon dioxide build-up: Deforestation

Forests have high rates of photosynthesis, which means a great deal of carbon
dioxide is removed from the atmosphere by the flora in forests. Therefore,
deforestation means that a lot less carbon dioxide will be removed from the
atmosphere, causing an increase in the CO2 levels in the atmosphere.

What is a fertiliser?
Farmers add fertilisers to their crops in order to make them grow faster.

This increases the yield of the crop, so the farmer makes more profit.
Fertilisers can be natural or artificial (man-made).

Types of fertilizers
The most common
fertilisers contain
nitrogen, phosphorous and potassium.

The numbers tell us

the relative percentage
of each element,

Farmers can choose

how much of each
element to add to make
their crops healthy.

What is Eutrophication ?
Fertilisers are water soluble, so are easily leached out of the soil and washed into
rivers and lakes. Algal bloom occurs - the algae absorb the fertilisers and grow
rapidly.

This means that the algae will blanket the surface of the lake, blocking sunlight from
the plant life below.

Algae and plants below the surface die as a result.

Bacteria decompose the dead algae and plants, using up the oxygen in the water for
respiration, causing the animals to die, too.

Test for Vitamin C

Use DCPIP

- Add sample to DCPIP while shaking it

Positive result = DCPIP turns colorless

Negative result = still the same (blue)
Potometer experiment

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