Cell Function, types (in process of drafting)

Cell Organelles: Cell structures that coordinate and function within the cell.

Organelles without membrane: cell wall, ribosome, cytoskeleton are

non-membrane-bound cell organelles. Both cells

Single membrane-bound organelles: vacuole, lysome, golgi apparatus,

endoplasmic reticulum in eukaryotic cells.

Double membrane-bound organelles: nucleus, mitochondria, chloroplasts in

eukaryotic cells.

Plasma/cell membrane: Selectively permeable membrane present in plant & animal cells.
Structure = fluid mosaic model
Function = providing shape and protects inner contents

Cytoplasm: present in plant & animal cell.

Structure = jelly-like substance
Function = holds organelles in place, protects them from damage.

Nucleus: Eukaryotic cell containing genetic material and chromosomes

Structure = large and spherical with pores and a nucleolus
Function = management of cellular processes. Pores able molecules to move in and out of nucleus. Nucleolus assembles
ribosomes

Endoplasmic Reticulum:
Structure = Network of membranous complex canals substances transported
Rough: tubules & vesicles involved in protein manufacture ribosomes attached
Smooth: storage and formation of lipid production

Mitochondria:
Structure = surrounded by a double-membrane system, inner and outer membrane
Function = Site of cellular respiration. Inner membrane highly folded that provide an increase in the surface area. This allows a
greater space for processes that happen across this membrane such as ATP Adenosine triphosphate energy production.

Plastids:
Structure =
~ Module 1: Cells as the basis of life ~ .
Cellular structures:

Prokaryotic - single cell organisms Eukaryotic - single celled or multicellular

Membrane-bound and non-membrane bound organelles

Membrane-bound organelles only present in eukaryotic cells, enclosed

by plasma/cell membrane: nucleus, rough/smooth endoplasmic
reticulum, golgi apparatus, lysosomes, mitochondria, vacuole,
chloroplasts. Prokaryotic cells split into
two domains: bacteria and archaea. Don’t have membrane-bound
structures, DNA bundles together in a region called the nucleoid.

TOPIC 2 : FUNCTIONS OF CELL ORGANELLES

Cell organelles Location Function Microscope
1. Enclose the Separates the interior of the cell from the outside environment and Electron,
Plasma/cell cytoplasm helps in the exchange of materials in and out of the cell. light
Membrane

2. cell cytoplasm The site of cellular respiration (production of energy as ATP). Glucose Electron
Mitochondria enters the mitochondria which is then changed into energy.
3. Cell cytoplasm Modification of proteins and lipids received from the endoplasmic Electron
Golgi Body reticulum. Sorting, packaging and storage of proteins and lipids.
Transport of these materials in vesicles through the cell.

4. Rough cytoplasm Synthesis, folding and modification of proteins. Transport of proteins Electron
Endoplasmic through the cell and membrane synthesis.
Reticulum
5. Smooth Cytoplasm Synthesis of lipids. Membrane synthesis with rough ER. Carbohydrate Electron
Endoplasmic metabolism, transport of these materials through the cell and
Reticulum detoxification of drugs and proteins.

6. Throughout the Breaks down foreign materials using enzymes such as amylase Electron
Lysosome cell
7. Nuclear Encloses nucleus Barrier separating the contents of the nucleus from the cytoplasm Electron
Membrane
7. Nucleus Variable location Contains most of the cell’s genetic material. Responsible for regulating Electron,
all the activities of the cell light
8. Within the nucleus Synthesis of ribosomal RNA; assembly of ribosomal subunit. Helps to Electron
Nucleolus make the RNA’s ribosomes
9. Chloroplast Cytoplasm of plant The site of photosynthesis. Contains the green pigment known as Electron,
leaf cells chlorophyll. light
10. Outside the Protects the cell. Maintains cell shape. Prevents excessive water uptake. Electron,
Cellulose cell plasma membrane light
wall
 11. Fills space Jelly like substance to maintain an optimal environment for the cellular Electron,
Cytoplasm bounded by cell organelles light
membrane
12. attached to High SA to VR allowing more efficient movement across the ribosome Electron
Ribosome endoplasmic membrane and produces proteins.
reticulum

Photosynthes Plants convert the Sun's energy into chemical energy stored in sugars such as glucose producing their food.
is Plants take in carbon dioxide through leaves from air, water absorbed from soil to roots = food (glucose,sugar) &
produces water, oxygen
Chlorophyll green pigment trapping energy from sun, starch is made from the glucose that comes from
photosynthesis.
Factors affect rate of photosynthesis: Light intensity, temperature, level of carbon dioxide within the air.
Light phase: light absorbed by chlorophyll, splitting of water molecules occurs, forms oxygen hydrogen ions, light to
chemical energy adenosine triphosphate formed, in
grana of chloroplast.
Dark phase: carbon dioxide is fixed into glucose
molecules using hydrogen ions and energy obtained
during the light phase, in Stroma.

Cellular Chemical bonds in glucose are broken down with/out oxygen providing energy (ATP) in a form of chemical process, cellular respiration.
Respiration Stage 1: Glycolysis, splitting 6-carbon sugar molecule into two 3-carbon molecules called pyruvate, 2 molecules of ATP are gained.
Stage 2: Oxygen breakdown of pyruvate into carbon dioxide & water. ATP released, 36 molecules of ATP formed.
Cell The fluid mosaic model: structure of plasma membrane, 2 layers of phospholipid molecules: cell recognition & communication with other cells.
Membrane Glycolipids: surface receptors, stabilise membrane, aid tissue assembly.
Glycoproteins: cellular recognition & immune response, membrane stability.
Functions:
●​ Double phospholipid layer: barrier, allows diffusion of oxygen and carbon dioxide.
●​ Embedded proteins transport amino acids; protein channels move water and dissolved
substances.
●​ Carbohydrate molecules recognize foreign cells or
molecules

Vocab Equilibrium - concentrations equalise and net movement is 0 absence of a concentration gradient, ensuring a balanced state
Concentration Gradients - difference between two point
Concentration - measure of how much solute is present per volume of solvent
Permeable - membrane cross particles. Semi Permeable - some particles cross membrane Non Permeable - no particles, ions, water cross membrane

Passive Diffusion/osmosis allow cells to intake materials and expel waste without energy expenditure
Transport Influenced by temp. Temperature increases, particles/water molecules move faster due to increased kinetic energy=rate of diffusion/osmosis increases.
concentration gradients facilitate movement of particles/water molecules: if cell has high salt concentration, water moves in to dilute it.

Diffusion Movement of particles from areas of high (extracellular fluid) to low (cytoplasm) concentration through permeable membrane (spreads)
Simple - Through phospholipid bilayer membrane of small particles, move along the concentration gradient.
Facilitated - Large particles can’t easily diffuse through the phospholipid bilayer membrane, assisted by carrier proteins to aid diffusion

Osmosis Movement of water from area of high water concentration (low solute) to regions of low water concentration (high solute) to balance solute levels through a
semipermeable membrane. absorbs From hypotonic to hypertonic solution.
Solute Hypotonic Solution = Surrounding solute concentration is lower than inside the cell, causing water to move into the cell, leading to swelling and potential
concentrations bursting (cytolysis). This process is called endosmosis.
of fluids Isotonic Solution = solute concentration surrounding cell is equal to inside the cell. Equal salt concentration
surrounding Hypertonic Solution = Surrounding solute concentration is higher than inside the cell, causing water to leave the cell, resulting in shrinkage (plasmolysis). This
cell movement of water out of the cell is known as exosmosis.

Active Low to high concentration against concentration gradient, metabolic energy released from the breakdown of ATP with vesicle transport endocytosis and
Transport exocytosis

Exocytosis Exocytosis expels cell material enclosed in vesicles travelling along microtubules to fuse with cell membrane & release their contents into extracellular fluid,
used for exporting proteins, eliminate waste.

Endocytosis Cell membrane pulled inward, surrounds material pinched into vesicle to remove from extracellular space into the cell.
Pinocytosis where cell membrane folds inward creating channels for liquid encircled in pinocytic vesicle.
Phagocytosis where cell membrane engulfs solid materials into phagocytic vesicle.

Cell Autotroph: make its own food, obtain organic compounds by converting inorganic matter, self-maintaining e.g. plants-photosynthesis
Requirement Heterotroph: consumes other materials obtain organic compounds from autotrophs or other heterotrophs; consumers. E.g. animals and
humans
Chemotrophs: prokaryotic organisms e.g bacteria use inorganic substances, iron, sulphur compounds from Earth's crust as their source of
energy in hostile environments.
organism that manufactures its own food through chemosynthesis (the oxidation of inorganic chemical compounds) as opposed to
photosynthesis. Mushroom bacteria
Producer: produces its own carbohydrate → glucose
Consumer: an organism that eats plants and animals for energy.
Organic: Large molecules structure based on carbon atoms, produced by living things Amino acids - protein building, lipids
Fatty acids - form cell membranes, Sugars (carbohydrates) – used for respiration, Vitamins-nucleic acids
Inorganic: small molecules,ions may/not contain carbon (except CO2). water, carbon dioxide and salts eg. sodium chloride and calcium
phosphate. chemicals dissolve in water to form ions. Ions are charged particles.
Water – approx 70% -90% of all living things, Minerals - Carbon Dioxide-Nitrogen-Oxygen
Carbohydrates are important sources of energy in cells. They include sugars, starch, glycogen and cellulose.

SA:VR Higher ratios improve efficiency of material exchange across cell membranes. As a cell increases in size, its SA:VR decreases.
Small cells/organisms have higher SA, supports better nutrient uptake & waste removal.

Enzymes Enzymes are biological catalysts containing proteins to control the rate of reaction. E.g sucrose
An enzyme reaction occurs when:
substrate (sucrose) + enzyme (sucrase) = enzyme-substrate complex = product
(glucose, fructose) + enzyme (sucrase) this is then released from active site.
Active site contains 3-4 amino acids.
 Environment Environmental factors such as temperature, pH level and substrate concentration all impact on enzyme activity, enzymes denature
al Factors changing shape and they can no longer function.
Temperature: number, types and sequence of amino acids doesn’t change when enzyme heated, but 3D shape of the molecule does,
damages the enzyme molecule permanently. Shape no longer fits the substrate & enzyme can no longer work.
Cooling also changes the shape of the molecule but this change does not permanently stop the enzyme from functioning.
pH - Each enzyme also has a specific pH at which it works best (optimum pH) but enzymes are rapidly denatured either above or below that
optimum.
Substrate Concentration - Amount of substrate present that can be turned
into a final product (enzymes bind to and change substrates into this final
product) Increasing substrate concentration can increase the rate of reaction
to a certain point. Once all of enzymes binded, substrate increase will have
no effect because they are working at their maximum, constant plateaus.
Inhibitors can bind to enzymes and stop them form functioning correctly.

\
~ Module 2: Organisation of living things ~ .
Organisation of cells:
I.Q How are cells arranged in a multicellular organism?
JUSTIFY THE HIERARCHICAL STRUCTURE ORGANISATION OF ORGANELLES, CELLS, TISSUES, ORGANS, SYSTEMS AND ORGANISMS
Hierarchical structure for life that organises itself from:
Cells--> Tissues--> Organs --> Organ Systems --> Organisms
Cells with specialised structures & functions group together to form tissues, which combine to create organs like the heart and stomach. Organs collaborate as organ systems, like
the digestive and circulatory systems. An organism is a combination of all the systems working together to maintain, grow and reproduce itself. Additionally, organisms function
within a greater system like ecosystem, depend on their interactions to maintain and grow itself.
COMPARE THE DIFFERENCES BETWEEN UNICELLULAR, COLONIAL AND MULTICELLULAR ORGANISMS

Unicellular Organisms Colonial Organisms Multicellular Organisms

Single celled, cannot form specialised tissues, lack tissues, Single celled, organisms of a mass of cells evolved to live Multiple cells specialised for different function. Cells
organs, can live independently. Prokaryotic (bacteria) together in group or colony, can live independently. become organised into groups called tissues.
eukaryotic (protists). Colonial state occurs when single cell protist are in an Numerous small cells for large SA:VR allows materials to
Small size = high SA:VR environment lacking resources. diffuse more efficiently.
Rid of wastes by diffusion across cell membrane E.g A coral colony is made up of a group of individual
Flagella & Cilia for cell movement through a medium polyps.
towards food, away from toxicity predation. Algae, coral, slime moulds.
Cells all possess cell membranes, cytosol, ribosomes and some sort of genetic material. Differences occur in the number of cell present in the organism, the types of cells and the
organisation of the cells.
INVESTIGATE THE STRUCTURE AND FUNCTION OF TISSUES, ORGANS AND SYSTEMS AND RELATE THOSE FUNCTIONS TO CELL DIFFERENTIATION AND SPECIALISATION
Cell structure & structure and arrangement of these cells in the organism are related to their specific function. Develop suitable structural features that allow them to carry out
specialisation their specific function: this makes them structurally different from other types of cells and from the embryonic cells from which they arose. Organisms rely on
related to it’s cell specialisation and differentiation to control the function of cellular processes, tissues, organs and systems. The functionality can be divided into levels or a
function hierarchy, each of which is dependent on the other.
Forming specialised Cell specialisation refers to the particular functions that a cell has.
cells Cellular Differentiation is the process that a stem cell goes through to become specialised. Each cell has the potential code to change into different cell types,
not change in DNA sequence, but is switching off many genes not needed in a particular tissue.
Adult stem cells divide and create fully-differentiated daughter cells during tissue repair and during normal cell turnover.
Examples of 2 processes: keep cells alive & special functions of the tissue, this requires the cells to have spherical shapes, sizes, or features.
specialisation Red blood cells carry oxygen & haemoglobin (increasing cell’s oxygen capacity) around the body the biconcave shape of red blood cells increase SA:V allowing
rapid diffusion of oxygen.
Specialised animal Nerve cells specialised to carry electrical messages from one part of the body to another, seen in long length & insulated fibres.
cells Muscles cells specialised to contract & shorten repeatedly.
Specialised plant Guard cells bean shaped cells in lower leaf epidermis, tiny pores in leaf surface necessary for gas exchange, open & close according to water availability.
cells Xylem cells transport water in plant, walls strengthened by lignin, phloem transports nutrients around plant.
Leaf cells contain chloroplasts for photosynthesis. In palisade cells. Water reaches sites of photosynthesis via the xylem cell (which are specialised dead cells)
after entering the plant from the soil through the roots.
I,Q: What is the difference in nutrient and gas requirements between autotrophs and heterotrophs?
INVESTIGATE THE STRUCTURE OF AUTOTROPHS THROUGH THE EXAMINATION OF A VARIETY OF MATERIALS, E.G: DISSECTED PLANT MATERIALS, MICROSCOPIC STRUCTURES, USING A RANGE OF IMAGING TECHNOLOGIES TO DETERMINE
PLANT STRUCTURE.
Plants are producers & autotrophs (make their own food). Vascular plants have a network of transporting substance through the tissues of xylem & phloem as the organs work
together in order for the plant to function correctly and to reproduce. Organs such as leaves, roots, flowers, stems and seeds all are connected together via a vascular system, which
distributes organic material and requires specialised cells. While non vascular plants do not contain the transport system.
Vascular Plants

Shoot system Root system

Leaf Vascular System Roots acts as

Function of leaf is to absorb sunlight and produce glucose in the process of anchorage,
photosynthesis. Leaves are the site of transpiration, process of water Stem absorption of
evaporating from leaf. Aids in movement of water from roots to leaves and Structural support & transport pathway between shoot & root systems. The water, inorganic
cools plant. conducting tissue is arranged in a ring or scattered throughout the stem tissue. nutrients from soil
External: Green when young, woody when old. Tip of stem is a terminal bud, growing using fine root
Waxy cuticle reflects heat, reduces water loss. Petiole attaches leaf to stem. point for the plant where stems support the flowers & fruit of the plant. hairs increase SA of
Leaf blade, thin & flat provides large SA:V for absorption of light, oxygen Co2 Upper & lower epidermises forms an impermeable layer protecting inner cells root to facilitate
for photosynthesis & gas exchange. & preventing water loss. Stomata have microscopic pores for exchange of gases absorption
on young green stems while older woody stem have lenticel for gaseous efficiently through
Internal:
exchange instead. osmosis. Area of
Chloroplasts are located in the mesophyll region of the leaf. high water
Pith distribute nutrients throughout the plant before storing them within its
(site of photosynthesis) cells. Some stems hollow, with no pith. concentration, low
Palisade mesophyll site where most photosynthesis occurs. Cortex diffuses water, nutrients into inner vascular structures & storing starch. solute (in soil) to
In the ground tissues, spongy mesophyll has loosely packed cells to provide Cambium cells undergo cell division to form xylem & phloem tissue. area of low water
air sacs between cells for the circulate of gases to assist in gas exchange. concentration, high
Since gas exchange occurs through stomates controlled by guard cells, solute (in root hair
chloroplasts (photosynthetic cells) are structurally close to gain gases they cells).
require.
 Xylem Phloem

The walls of xylem cells are lignified: Sugars distributed

Cells of the xylem grow to maturity & die, but are around plant through
kept open by a material called lignin. Lignin is the phloem tissue in a
major component of wood. In woody plants, old bidirectional way. Made
xylem cells form growth rings in the stem as the plant of sieve cells with sieve
grows & the xylem vessels are thickened with this plates have
woody material. Xylem tissue is made up of long perforations (holes) to
tubular cells which join into 'pipes', that form the allow flow of sugars &
vascular system of ferns, gymnosperms and organic materials along
angiosperms, called vascular plants. Provides the tubes. Supported
support, strength to stem, allowing the xylem to by Companion cells
withstand pressure changes as water moves through regulate the flow of
the plant. substances providing
Responsible for transporting water, nutrients & energy for active
mineral ions upwards from roots to leaves in 1 transport of sugars in &
direction absorbed from the soil through the root out of phloem.
system.
Xylem tissue is made of dead cells tracheids that form
hollow tubes.

How does the composition of the transport medium change as it moves around the organism?
COMPARE STRUCTURES & FUNCTION OF TRANSPORT SYSTEMS IN ANIMALS & PLANTS,: VASCULAR SYSTEMS IN PLANTS AND ANIMALS , OPEN AND CLOSED TRANSPORT SYSTEM IN ANIMALS
Transport in Plants:
Transport in Water movement driven by Transpiration-Cohesion-Tension Theory.
xylem Water moves from cell to cell within the plant by osmosis until it reaches the xylem cells.
1.​ Cohesion - Molecular attraction between “like” molecules, stick together. Due to
hydrogen bonding between water molecules, where the positive end is attracted
to the negative end of the water molecules in the xylem cells.
2.​ Adhesion - Molecular attraction between “unlike” molecules stick to different
substances. E.g Between water molecules and the molecules of the xylem cell
walls.
3.​ Transpiration - 1 water molecule evaporates out of the stomate, another is ‘pulled’
up the column of water in the xylem to replace it. Another molecule of water
moves by osmosis into the bottom of the xylem to replace the one that has moved
up
4.​ Tension - Loss of water vapour due to the evaporation in transpiration at the
leaves, creates negative water pressure at the leaf surface enabling water to move
upwards through xylem.
5.​ Transpiration Steam - The movement of water from the roots through the xylem
to the leaves.
6.​ Water's surface tension allows certain organisms to float, move, and even live on
the water's surface. Surface tension is a property of liquid that allows it to resist an
external force. It is caused by the cohesive forces between liquid molecules.
Movement of Phloem transports sugars from regions that produce or store sugars called sources (leaf). They produce sugars
sugars in through photosynthesis in the form os sucrose are as stored sugar starch like in the roots. To places in the plant
phloem that need sugars called sinks (root).
When sugar is actively transported into the phloem from a source, it creates an area of high sugar concentration.
This causes water to passively move into the phloem from the xylem, to dilute the sugar. This water movement
creates temporary pressure, causing the movement of materials in the phloem towards the various sinks. At a sink,
sugars are travelling down the concentration gradient and so can be moved passively into the sink, causing water
to move out of the phloem and into the xylem by osmosis. At times, sugars are also moved actively into sugar
sinks.
Translocation in the process of moving sugar from a source to a sink.
Sieve plates in phloem tissue allow flow of sugars through perforated barriers.

INVESTIGATE GAS EXCHANGE STRUCTURES IN ANIMALS/PLANTS THROUGH: MICROSCOPIC STRUCTURES -ALVELOI IN MAMMAS AND LEAF STRUCTURE IN PLANTS MACROSCOPIC STRUCTURES- RESPIRATORY SYSTEMS IN A RANGE OF ANIMALS
INVESTIGATE THE EXCHANGE OF GASES BETWEEN INTERNAL AND EXTERNAL ENVIRONMENTS OF PLANTS AND ANIMALS
Plant gas Structures: Leaves have outer layer called epidermis, waxy coating helps reduce water loss.
exchange Stomata - Gas exchange in leaves (thin, flat to increase SA for photosynthesis) is facilitated through stomata microscopic pores where chloroplasts are found they are
surrounded by guard cells controlling when stomata open/close to reduce water loss from plant. Stomates located in lower epidermis where
Carbon dioxide enters through stomata & diffuses through spongy mesophyll cells into the palisade mesophyll where most photosynthesis occurs. Oxygen & water
exit through the open stomata.
Lenticels - pores in woody stems of plants provides gas exchange for phloem tissue. Gases needed for respiration by the cells of the stem are exchanged by diffusion.
Roots - Atmospheric oxygen in soil particles diffuse into root hairs & reach root cells utilised in respiration. Carbon dioxide produced in root cells during respiration
exit through the same root hair by diffusion.

Animal Respiratory systems aid in gas exchange. Structures differ between animals, most common structural features: moist, thin membrane, rich blood supply & large, large SA.
gas Insects exchange gases with the atmosphere using trachea, tracheoles and spiracles. Spiracles have fine hair-like structures to prevent dust entering the system. Trachea
exchange and smaller internal tracheoles are a series of internal tubes that connect to the outside through holes (spiracles). In tracheoles, cells are close to specialised gas
exchange surfaces, small size increases SA:VR of insect to maximise diffusion rate of gases around their body. Diffusion facilitated by abdominal movements that flushes
air in/out of tracheal system.
Waste carbon dioxide concentration higher in cell than trachea = waste diffuse out of cell.
Oxygen levels are higher in the trachea than the surrounding cell, oxygen will diffuse into cell.
Fish - gills contain gill arches to support filaments & lamellae. Lamellae increase SA available for gas exchange.
Gills require water to flow past them to ensure maximum diffusion of oxygen.
As the fish opens its mouth, water flows in the direction past the gills, where gaseous exchange takes place. The deoxygenated water exits through the fish gills or lits.

Amphibians, frogs - frogs in larval stage (aquatic stage) develop internal & external gill for gas exchange. Semi terrestrial ( adult-stage) lungs developed to exchange gas
through skin & within mouth.
subcutaneous breathing - Oxygen from air diffuses into moist skin, transported by the blood to the heart, from where it is sent directly to the body.
Air is passed in and out by the pumping movement of the floor of the mouth (known as the buccal pump), and the opening and closing of the nostrils.
Human gas Through respiratory system contains structures of lungs (alveoli) & airways (trachea, bronchi & bronchioles).
exchange Air inhaled filtered through trachea that branches into tubes bronchi & bronchioles leading into lungs. Branching of these tubes increases SA to maximise gas
exchange. Exchange of oxygen & carbon dioxide occurs in alveoli small sacs surrounded by blood vessels known as capillaries. Blood transports oxygen to body cells
used in cellular respiration to produce energy. Carbon dioxide is produced as a waste product & is transported by the blood to the alveoli to be exhaled.
The alveoli allows deoxygenated blood -> oxygenated . In respiration, the blood returning to the lungs is low in oxygen and high in carbon
dioxide and the alveoli are high in oxygen and low in carbon dioxide.
Blood flows past the alveoli through the capillaries, oxygen moves into the blood & carbon dioxide moves from the blood into the alveoli through diffusion.

Digestion • Physical digestion -> the physical breakdown of the food into small pieces to increase the SA for the
Process action of enzymes.
• Chemical digestion -> digestive enzymes chemically breakdown large complex molecules into smaller, simpler forms, making a new substance.
o Mouth using enzymes (amylase), in the stomach where it secretes hydrochloric acid activating pepsin, an enzyme that breaks down proteins. The contractions of
the stomach allow further mechanical breakdown of the food to increase SA in contact with pepsin.
o Protease acts on proteins, Lipase acts on lipids and maltase acts on carbohydrates.
o Pancreas produces more digestive enzymes and insulin. Liver produces bile, increasing pH of contents, breaks down fats to allow for a large surface area for lipase
to act on.
▪ Amylase -> breaks down carbohydrates, protease -> breaks down protein, lipase -> breaks down lipids.
• Absorption of nutrients, minerals, and water
o The products of chemical digestion are absorbed into body in small intestine, where sugars and amino acids pass into bloodstream by diffusion & fatty acids &
glycerol pass into the lymph.
o Simple carbohydrates, lipids and proteins are absorbed in the small intestine and water is absorbed in the large intestine.
o Small intestine contains folded membranes called villi which increase the surface area for the absorption of nutrients.
• Elimination of solid waste
o Rectum stores waste products of digestion (facese) until they are eliminated from the body through the anus.
Digestive Systems
Digestive Secretion Function
Mouth & Salivary Glands
Mucus Lubricates the food during chewing
Salivary amylase Digest starch into maltose
Stomach
Hydrochloric Acid (HCI) Initiates the digestion of protein and kills bacteria
Pepsin Starts protein digestion into peptides
Mucus Lubricates the food & protects the stomach lining form digestion
Intrinsic factor Aids in absorption of vitamin B12 by large intestine
Pancreas
Sodium Bicarbonate Neutralises stomach acids & activates digestive enzymes
Pancreatic amylase Digest starch & glycogen into disaccharides
Lipases Digests fats into fatty acids & glycerol
Proteases Digests proteins into peptides
Liver/gall Bladder
Bile Emulsify fats & neutralises acids
Small Intestine
Maltase Digest maltose into glucose
Sucrase Digest sucrose into glucose & fructose
Lactase Digest lactose into glucose galactose
Peptidase Digest peptides into amino acids
Nuclease Digest nucleic acids into sugar & nitrogen bases
Large Intestine Water, salts absorbed

Open circulatory systems do not require the large amounts of energy required by closed circulatory systems. They suit smaller animals that do not make long
sustained rapid movements.
Mammalian o Closed circulatory system with blood as the transport medium
Circulatory o System consists of a pump (the heart) which sends a fluid (the blood) through a network of
System tubes (blood vessels)
Blood vessels transport oxygen, nutrients, and hormones throughout the body, to and
from the cells and the external environment
The heart is the primary organ that pumps blood throughout the body. Steps:
o Oxygenated blood enters the heart through the pulmonary vein.
o Blood enters the left atrium from the pulmonary vein
o Blood flows through a mitral valve into the left ventricle.
o Blood flows through the aortic valve through to the aorta, where it is pumped out throughout
the body.
o Deoxygenated blood enters the heart through the superior and inferior vena cava, into the right
atrium.
o Blood flows through the tricuspid valve into the right ventricle.
o Blood flows through the pulmonary valve to the pulmonary artery.
o Blood flows from the pulmonary artery back into the lungs to become oxygenated.
Pulmonary circuit, deoxygenated blood leaves right ventricle of the heart via the pulmonary artery travels
to the lungs, returns as oxygenated blood to the left atrium of the heart via the pulmonary vein.
Systematic circuit, oxygenated blood leaves the body via the left ventricle to the aorta, then enters the
arteries and capillaries where it supplies the body's tissues with oxygen. Deoxygenated blood returns, via
the veins, to the vena cava, re-entering the heart's right atrium.
Blood Vessels Arteries carry blood away from the heart under high pressure. Thick, but elastic walls, made up of 3 tissue layers:
▪ endothelium as lining
▪ smooth muscle to contract the vessel
▪ connective tissue to allow for expansion
Veins carry blood back towards the heart, carries same quantity of blood as the arteries but not at the same high pressures 3 same layers as arteries, not as thick:
▪ endothelium, smooth muscle, connective tissue, veins contain valves preventing back flow of blood-flow in one direction.
Capillaries form the connection of arteries and veins, only one cell thick function is the exchange of materials between the blood and tissue cells by diffusion.
Blood is 90% water, a sticky yellow liquid that carries: salts, large plasma proteins (antibodies), waste materials, products of digestion (amino acids, hormones, sugars)
Composition Red blood cells (erythrocytes) Disc-shaped and biconcave, no nucleus → contains pigment haemoglobin transports oxygen (oxyhaemoglobin) & carbon dioxide
(carbaminohemoglobin)
White blood cells (leucocytes). 2 types (e.g. phagocytes and lymphocytes) larger than red blood cells, contains nucleus. Functions as part of the immune system ▪ 1
mL of blood contains about 4000-12 000 white blood cells
Platelets (thrombocytes) involved in haemostasis (stopping the flow of blood during injury), by causing the formation of blood clots, also known as coagulation.
Lymphatic system is a network of tissues & organs rid body of toxins, wastes, unwanted materials. Function is to transport lymph, a fluid
containing infection-fighting white blood cells, throughout the body.

The composition of blood changes as it moves throughout the body, depends on the organ it is moving
through.
• In all organs and tissues except the lungs, blood loses oxygen and gains carbon dioxide. In the lungs, it
gains oxygen and loses carbon dioxide.
• In all organs except the small intestine, blood loses nutrients, such as the products of digestion and gains
wastes. Blood gains products of digestion in the small intestine.
• In the kidneys, blood has less urea when it leaves, and the concentration of water and salts will have
changed according to the needs of the body.
• In the kidneys, the amount of urea is decreased because the kidneys filter nitrogenous wastes out of the
blood.
• Blood leaving the kidneys has the lowest percentage of nitrogenous wastes. Excess water and salts are
removed from the blood. In the large intestine, water, salts, and vitamins are absorbed into the blood.
• When blood passes through endocrine glands, hormones are added to the blood.
Photosynthes Photosynthesis is the process by which plants convert light energy into chemical energy.
is theories ▪ Jan Baptista van Helmont conducted experiment with willow tree, concluding that the tree's growth was due to water rather than soil -> early step towards
understanding photosynthesis. Conclusion was incorrect as he did not consider mass of leaves, no repetition or control variable.
▪ Joseph Priestley kept a burning candle & mouse together in the single bell jar. 1. Candle was extinguished, and the rat died. 2. Kept a burning candle, a rat, and a
green plant together in the bell jar where neither died. Allowed for the discovery of oxygen and its role in photosynthesis.Correct conclusion as other factors were
controlled.
▪ Jan Ingenhousz exposed a plant to light and dark and found the plant needed light to grow. Correct conclusion
~ Module 3: Biological Diversity ~ .
TOPIC 1 : EFFECTS OF THE ENVIRONMENT ON ORGANISMS/ADAPTATIONS
abiotic/biotic A selection pressure is any factor that promotes change in characteristics and adaptations of species that help them survive. Abiotic, biotic
selection Abiotic selection pressures are non living and include light availability, salinity, nutrient availability in soil. E.g Availability of light acts as a selection pressure on rain
pressures: forest plants where some species Epiphytes have competed for sunlight by growing on top of other plants.
Biotic selection pressures are living and include competition, predation & sexual selection. E.g Sexual selection has resulted in the bright colours and large feathers
seen in male birds/peacocks. As females are more likely to mate with an impressive display of these characteristics.
competition - interaction between species that both require a recourse in limited supply.
predation - biological interaction where one organism (predator) kills and eats another organism (prey)
sexual selection. A mode of natural selection in which members of one sex choose mates of the other sex based on preferred/certain characteristics.

Cane Toads Cane Toads - Cane Toads, introduced species in 1935, caused environmental damage due to their ability to poison predators, invaded native species & caused
competition. E.g Changes in Cane Toads have arisen longer legs give an advantage to spread faster across Australia. E.g Selection pressures on snake species resulting
in smaller heads and resistant to toxins.
Rabbits European rabbits were introduced in the 1850’s so they could be hunted for sport. They are an invasive species in Australia with a very high breeding rate, which
increased their population rapidly. Management involved the myxoma virus that was spread through mosquitoes that would transmit the disease and reduced the
European rabbits. They developed resistance over time.
Prickly pears
Cactoblastis moths was a successful example of a plant pest as a biotic selection pressure introduced in the 1920s to control the
number of prickly pear plants. This was successful as the eggs laid by cactoblastis moths developed into cactoblastis caterpillars and
would eat the prickly pear, causing the population to decline.
Impacts: Compete with native animals, cause soil erosion; removal of topsoil is devastating as it takes hundreds of years to generate because it’s
an organic component, eat farmers crops
Impacts
Plant Pest Animal Pest
Agriculture Affect farmer’s crops & grass through predation, as it’s required for
livestock like cows.
Native Wildlife, Soils Destruction of native plants results in soil and land degradation.
Compete with crops for water, nutrients and
space.

TOPIC 2 : ADAPTATIONS/ECOSYSTEMS
Adaptation Description Example 1 Example 2 Example 3

Structural physical feature of Penguins - thick layer of fat Kangaroo’s - powerful leg Some desert plants have
adaptation organisms, size & shape of (blubber) and dense feather muscles assist it in hopping at spines instead of leaves to
body parts to protect them from high speeds. reduce water loss.
freezing temperatures.

Behavioural Something an animal does in Penguins huddle together Kangaroo - will cool down by Nocturnal animals are only
response to the pressure to to stay warm. licking forearms and pant. active at night this helps
increase chances of survival avoid the heat of the day.

Physiologic Internal body process of the Penguins cool themselves Kangaroos have dense network Mangroves have ability to
al organism to regulate and by flushing blood through of blood vessels near surface of excrete salt using special
maintain homeostasis to their flippers and feet. skin of forearms which helps cool glands on their leaves.
survive. them down as the saliva
evaporates.

THEORY OF EVOLUTION BY NATURAL SELECTION

Charles Biodiversity: (the variety of all living species including animals, plants and microorganisms)
Darwin’s Ecosystem - biodiversity can be defined as the variety of different ecosystems within an area. This includes different habitats, communities and ecological processes.
Theory of Species - biodiversity is the number of different species found in a given area.
Evolution: Genetic - biodiversity is the variation of genes within a species.

Spent years exploring islands around South America including Galapagos where he recorded and collected the species he saw, his observations led him to develop
the theory of evolution by natural selection. From his observations, he proposed the idea that all living things had evolved from a common ancestor by means of
natural selection. He concluded that different continents with similar environments contain similar looking species. As Darwin explored the Galapagos islands noticed
tortoises and finches on different islands had different adaptations suited to their environment. E.g They had different beak sizes and shapes depending on food
available.
1.​ Evolutionary change in species occurs gradually
2.​ Evolutionary change is very slow
3.​ Variation in species occurs randomly
4.​ THe survival of species depends on their ability to cope in a changing environment in response to natural selection.
5.​ Speciation occurs as a result of species evolving from a common ancestor into less similar species over time. (Group of individuals interbreed with slight
different characteristics)
6.​ Natural selection aka Survival of the fittest, in which heritable traits help organisms survive thus becoming more common in a population over time.
Examples Darwin’s Finches - Scientists believe that finches evolved from a single from South America and migrated to the Galapagos islands. From here, the finch species
underwent divergent evolution and speciation over time and resulted in13 species of finches. Each species has individual differences suited to their ecological niche
depending on which island they lived on, & the environmental conditions, finches varied by their colour, leg length and beak size which adapted them to a particular
food source. Survival of the fittest: some birds thrived and reproduced & finches not adapted to the conditions died out. E.g beaks adapted to particular food source.
Grasping beak helps woodpecker retrieve insects out of cracks.
Peppered Moths - Colour change in the moth population as a consequence of air pollution during the Industrial Revolution. Pollution from smoke and soot killed off
lichens and darkened tree trunks. As a result, the paler moths became more visible to predators, while the darker variety became more camouflaged.
Types of Antibiotic resistance in bacteria - Genetic variations in bacterial populations make them resistant to the chemical as they will
evolution Gradualism - Gradual change in species over time. Evolves from common ancestor, selection pressure for colour of wings and gradually evolve small variation enable
them to survive and pass on these differences to their offspring. Over a long period of time, population changes due to these selection pressures.
Punctuated equilibrium - Species changes rapidly over a short period of time. Proposed by Eldrege and Gould, evolutionary change occurs in short periods of time in
response to sudden changes in the environment leading to speciation abrupt appearance of new species is a random event and is usually associated with large
number of mass extinctions.
Long periods without change, helpful mutation that occur in individuals are passed on. The proportion of the population that has the mutation changes.
Convergent Evolution - Anatomically dissimilar functions, then evolved to similar traits due to selection pressures. Unrelated species evolve to become more similar
structurally or behaviourally due to exposure to similar selection pressures. E.g Bats, birds all independently evolved wings as a result of exposure to similar
environmental pressures. Provides an advantage to fill an ecological niche where competition is low.
Divergent evolution - Diversification of species from related ancestor it’s where two or more closely related populations of a species become less similar over time.
Driving factors includes different populations of species being exposed to different selection pressures E.g Darwin’s Finches variations of selective pressures on island
from geographical isolation.
Allopatric Speciation - Populations are physically/geographically separated causing them to diverge independently and gives rise to separate species. E.g Califonian
salamanders.
Sympatric speciation - Species living in same physical & geographical area diverge into separate species due to behavioural changes in response to a selection
pressure such as competition for food. When divergence creates new distinct species from common ancestor e.g Darwin’s Galapagos finches, process referred to as
adaptive radiation.

Evidence for Microevolution - Mi = mini small scale changes over short period, changes within population but doesn’t produce new species.
evolution Evolution of horse
Speciation - Small changes in characteristics within a population can lead to speciation. Slow progressive accumulation of small changes over a long period
(microevolution)
Macroevolution - Ma = massive changers over longer time, results in the emergence of new species.
Evolution of platypus
TOPIC 4 : EVIDENCE FOR EVOLUTION
Palaeontology Palaeontology refers to study of fossils as their preserved remains of organisms or
their traces, dating from the distant past.
Transitional fossil - half-way fossil shows transition between 2 different evolutionary
groups. E.g archaeopteryx features both bird and reptiles suggesting shared common
ancestor before undergoing divergent evolution.
Relative dating determines the relative age of different rock layers. (which layers are
older or younger)
Absolute dating determines precise age of rock/fossils using radioisotopes. Carbon-14
half life of 5370 years.Fossils, Dating fossils
Comparative Shows similarities between closely related species by describing features of their
Anatomy body structure. E.g Homologous structures: similar features in different organisms
because common ancestry. five-fingered limb (pentadactyl limb). Homologies are the
result of divergent evolution.
Analogous Structures: features in different organisms that serve a similar function,
structurally different since evolved independently. Wings of birds, butterflies, bats.
Analogies result of convergent evolution.

Comparative Early-stage embryos of different species suggests that different groups have
embryology divergently evolved from a common ancestor.

Biogeography Species distribution across continents and over geological time supports continental
drift. The similarity of species on different continents indicates they were once joined
as the supercontinent Gondwana before drifting apart.

Biochemical Connections between species by comparing how closely their DNA matches. “The
evidence more closely related the organisms, the higher the similarity in their biochemical
makeup suggesting that they evolved from a common ancestor.”
Analyse sequence of amino acids of a protein common to many species, match the
similarities and then compare them with other species. Protein cytochrom c, low
numbers = similar. High number = less similar
DNA sequencing, compares number of matching parts in a common section of DNA. 4
letters represent DNA code: A, T, C, G
Identical genes (genetic code) in different organisms strengthens the theory that
organisms have changed over time through the process of evolution by natural
selection.
DNA hybridisation - identifies similarities in DNA structures by cutting DNA from
different species into short pieces (600-800 base pairs) & heating them to separate
the strands. When mixed, single strands from different species may join to form
hybrid molecules, not all base pairs will match due to sequence differences.
~ Module 4: Ecosystems Dynamics ~ .
What effect can 1 species have on the other species in a community?
Population Abiotic/biotic factors determine the distribution, abundance of species
Dynamics Distribution = geographical spread of a specie
Abundance = ​number ​of species ​present in a habitat
Limiting factors: light intensity significantly affects the rate of photosynthesis
and overall plant growth.
Selection pressure - a factor affecting the survival & reproduction of an individual within a
population.
Biodiversity -
Genetic diversity -
Species diversity -
Ecosystem diversity -
Bioindicators -
Macroinvertebrates -
Ecosystem - group of organisms & non-living environment interacting together,
self-sustaining.
Ecological niche: describes the functional position of an organism in it’s ecosystem.
This includes the:
1.​ Habitat - physical space it occupies in an ecosystem
2.​ Relationships - interactions with other species living within that
ecosystem, e.g predation, food chains.
Symbiosis:
mutualism - mutualism is when both organisms benefit from the relationship, (+/+ → win/win) e.g pollination: bee provided with food (nectar or pollen) and the plant’s pollen
is dispersed to reproduce.
Commensalism - commensalism is when one organisms benefits, while the other is unaffected (+/0 → win/neutral) remora fish attach itself to a shark, feeding on scraps
scattered by its host. The remora neither harms nor helps the host, shark remains unaffected.
parasitism - relationship between 2 organisms where 1 is benefited & the other is disadvantaged. (+/- → win/lose) Organism that is benefitted is called the parasite, while the
one that is harmed is called the host. Ticks feeding on dog’s blood.
Allelopathy - Plants produce allelochemicals into the soil to inhibit growth of other plants as competitors. Eucalyptus & casuarinas
Predation - predation affects the distribution and abundance of their prey → population control.
Competition - Both organisms compete for the same limited resources. Competition for light, tree canopy.
Impacts of mining on the biodiversity of an ecosystem - long lasting as it inevitably results in major habitat changes for the flora and fauna can be irreversible. Chemical waste
streams, altered topography, soil erosion, habitat loss, deforestation excessive fertiliser = soil acidification & runoff from excess nitrates, phosphates.
Ecological rehabilitation - Removing of hazardous materials (contaminated soils), physically reconstructing the landforms (valleys, stream channels to stabilise area from
erosion), revegetating the site (seedlings, trees provide habitat for local fauna to recolonise the site), soil testing (salinity, acidity, water, nutrient availability to understand best
plants that will efficiently be rehabilitated)
Human Selection Pressures - (indirect) Habitat destruction of deforestation, (direct selection pressure) hunting, climate change fossil fuels increased from greenhouse effect.
Extinctions -

Sampling Equipment & method Advantages Disadvantages

Techniqu
e

Transects A form of line you walk along, study is undertaken by moving Causes minimal disturbance to the Not accurate and cannot cover long
along the line & recording which species are located at each point. environment. distances. Only used on non-moving
Illustrates a particular gradient or organisms.
linear pattern along which species of
plants and animals are living.

Quadrat 1㎡ frame placed randomly on the ground throughout the study Quick, inexpensive. Used on slow moving plants and
Sampling area. Number of species in the quadrat is recorded. Complete Minimal disturbance of environment. animals and not accurate.
several & calculate average.

Capture-r Tags to mark the animals. Good for determining population of Only works for fast moving animals.
ecapture Calculated by the number of animals in the first capture x number animals. Cannot calculate the diversity of the
of animals in the second/number of recaptured environment.
Population Abiotic/biotic factors determine the distribution, abundance of species
Dynamics Distribution = geographical spread of a specie
Abundance = ​number ​of species ​present in a habitat
Limiting factors: light intensity significantly affects the rate of photosynthesis
and overall plant growth.
Selection pressure - a factor affecting the survival & reproduction of an individual within a
Population - refers to the no. of organisms living in a certain area at a certain time.
Consequences of predation - Factors affecting it: reproduction rate, ratio males to females, availability of prey’s
food, age of reproductive maturity, no. of reproductive episodes per lifetime.
Consequences of competition - Population fluctuations linked to competing species & their recourse. Food source
available both species increases, food sources decrease, abundance of both competing species decreases. Species sharing same environment, one species more successful than
the other that has an advantage, adaptation, driven to low numbers, or extinction.
Gause's law, proposes that 2 species competing for the same limiting recourse cannot coexist at constant population values. If two species live on a single resource, the one
with a slight advantage will dominate & out-compete the other, resulting in the less adapted specie to extinction or finding a slightly different niche. E.g fish feeding on algae
instead of berries.
Consequences of disease - Affects normal functioning of tissues in a living organism (infectious, non infectious diseases) E.g devil facial tumour disease for Tasmanian devils is a
clonally transmittable cancer highly contagious, through social interactions. Results in altering the balance and disruptions of food webs dramatically. The affected species will
suffer a decline in population numbers, predators (no source of food) and the species’ prey become overpopulated.

Evidence for Paleontological & geological evidence is used to provide insight into past ecosystems.
Evolution Aboriginal rock paintings give clues about the environment and the effect of climate change on local flora & fauna depicting their abundance, also shows megafauna bird
Genyornis coexisted with humans. E.g Lush open tropical forests to ecosystem of scrub & open grassland. Wndjina in the West-Kimberley region, shows extinct megafauna,
Thylacoleo. Use radiometric dating methods to give accurate dates for the paintings.
Ice cores from glaciers reveal information about past climates. Gradual accumulation of snow forms a timeline, ice furthest away being the oldest & the ice on top is the most
recent. Seasonal differences form visible annual bands & layers. Gas bubbles trapped can determine concentration of atmospheric gases like carbone dioxide. Volcanic ash can
be present, indicating a historic event. Precipitation rates can be inferred from the thickness of annual ice core layers. Temperatures determined with mass spectrometry to
analyse presence of isotopes within water molecules. E.g water includes deuterium (isotope of hydrogen) & oxygen-18.
Gas analysis is extracted from the frozen bubbles in ice cores where carbon dioxide known as a greenhouse gas enables scientists to study the changes of atmospheric carbon
dioxide over time and the greenhouse effect.
Radiometric dating determines how much time has passed since rocks formed by measuring the radioisotopes halflife. E.g carbon 14 takes 5730 years to decay to it’s halflife.
We use carbon dating to determine the age of rock fossils. Only records until 50 000 years.
Halflife is the time it takes for half of the original sample to halve, different radioisotopes have different half-lives.
Daughter isotope is when a parent isotope breaks down or decays, it turns into another isotope.
Banded iron formations are sedimentary deposits where a sea contained dissolved iron. First organism photosynthesised giving off oxygen where it bonded with dissolved
ferrous iron & formed insoluble ferric oxide (iron oxide) Found in Hamersley Ranges in Western Australia.
Paleontologic Evidence preserved in amber where bacteria prevented from breaking down organic material, replacement of body tissues by minerals (opals), impression in mud
turned to rock or preservation of whole organism in ice. Fossils provide clues about the environment.
E.g finding fish fossils indicates aquatic environment. Foraminifera are single-celled protozoans containing calcium carbonate, oxygen isotopes locked in shell of these
microfossils. Stromatolites made by cyanobacteria which are photosynthetic found in WA from 3.8billion years ago.
Matching coast lines like jigsaw fit & corresponding fossils through the law of faunal succession groups of fossil animals & plants occur throughout the geologic record in a
distinct and identifiable order. E.g Glossopteris plant distribution among the first evidence for continental drift.