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The basic structural and functional unit of all living organisms.
Cell membrane nucleus cytoplasm mitochondria and ribosomes.
Cell wall vacuole and chloroplasts.
It contains the genetic material (DNA) and controls the activities of the cell.
The site of aerobic respiration where energy (ATP) is released.
The site of protein synthesis.
Controls what substances enter and leave the cell.
The site of photosynthesis where light energy is absorbed by chlorophyll.
Provides structural support and shape to the cell. Made of cellulose.
Contains cell sap and helps maintain turgor pressure to keep the cell firm.
A cell with no membrane-bound nucleus. DNA floats freely in the cytoplasm. Example: bacteria.
A cell with a true membrane-bound nucleus. Examples: plant and animal cells.
The net movement of particles from an area of high concentration to an area of low concentration down a concentration gradient.
The movement of water molecules through a partially permeable membrane from a region of high water potential to a region of low water potential.
The movement of substances against a concentration gradient using energy from respiration.
Magnification = image size divided by actual size
Undifferentiated cells that can divide and differentiate into specialised cell types.
The process by which a cell becomes specialised for a particular function.
Two genetically identical diploid daughter cells.
Growth repair and asexual reproduction.
Glucose + oxygen → carbon dioxide + water (+ energy)
Glucose → lactic acid (+ energy)
Glucose → ethanol + carbon dioxide (+ energy)
Anaerobic respiration in yeast producing ethanol and carbon dioxide.
Carbon dioxide + water → glucose + oxygen (using light energy)
Both low light intensity and low temperature.
It absorbs light energy (mainly red and blue wavelengths) to power the reaction.
In the chloroplasts mainly in the mesophyll cells of leaves.
Light intensity carbon dioxide concentration and temperature.
To allow gas exchange (CO2 in O2 out) and water vapour to leave the leaf.
The loss of water vapour from the leaves of a plant through the stomata.
To transport water and dissolved minerals from the roots up to the leaves.
To transport dissolved sugars (sucrose) from the leaves to the rest of the plant (translocation).
Add iodine solution — it turns blue-black in the presence of starch.
Add Benedict's solution and heat — it turns from blue to brick-red/orange if glucose is present.
Add biuret reagent — it turns from blue to purple/violet in the presence of protein.
Add ethanol then water — a white milky emulsion forms if lipids are present.
Biological catalysts that speed up chemical reactions in living organisms.
The specific region where the substrate binds to form an enzyme-substrate complex.
The substrate fits exactly into the active site of the enzyme like a key fits a lock.
It denatures — the active site changes shape so the substrate can no longer bind.
Around pH 7 (neutral) though some like pepsin work best at acidic pH.
Amylase (produced in the salivary glands and pancreas).
Proteases (e.g. pepsin produced in the stomach).
Lipase (produced in the pancreas).
It emulsifies fats into smaller droplets increasing the surface area for lipase to act on.
Produced in the liver and stored in the gall bladder.
Glucose (simple sugars)
Amino acids
Fatty acids and glycerol
To carry oxygen around the body using haemoglobin.
To make more room for haemoglobin to carry oxygen.
To defend the body against infection by ingesting pathogens or producing antibodies.
To help blood clot at a wound to prevent blood loss and infection.
The liquid component of blood that transports dissolved substances including glucose CO2 hormones and urea.
It binds to oxygen in the lungs to form oxyhaemoglobin and releases it at the tissues.
Arteries carry blood away from the heart under high pressure with thick muscular walls. Veins carry blood to the heart under low pressure and have valves.
To allow exchange of substances between the blood and tissues due to their thin walls and large surface area.
A condition where the coronary arteries become narrowed by fatty deposits (plaques) reducing blood flow to the heart muscle.
Right atrium right ventricle left atrium and left ventricle.
To pump oxygenated blood out to the body through the aorta. It has the thickest muscular wall.
Microorganisms that cause infectious disease. They include bacteria viruses fungi and protists.
They reproduce rapidly inside the body and produce toxins that damage tissues.
They invade cells and use the cell's machinery to reproduce then burst out destroying the cell.
Measles influenza HIV or COVID-19.
Salmonella food poisoning or tuberculosis (TB).
Malaria (caused by Plasmodium spread by mosquitoes).
Proteins produced by white blood cells (lymphocytes) that bind to specific antigens on pathogens and neutralise or destroy them.
Active immunity involves the body producing its own antibodies (after infection or vaccination). Passive immunity involves receiving antibodies from another source (e.g. mother's milk or injection).
They introduce a weakened or dead pathogen (or its antigens) to stimulate the immune system to produce antibodies and memory cells without causing disease.
Medicines that kill or inhibit the growth of bacteria. They do not work against viruses.
Bacteria evolve resistance through natural selection and overuse of antibiotics speeds up this process making infections harder to treat.
The brain spinal cord and a network of nerves (neurons).
A rapid automatic response to a stimulus that does not involve conscious thought from the brain.
Stimulus → receptor → sensory neuron → relay neuron (in spinal cord) → motor neuron → effector → response
Muscles (which contract) and glands (which secrete hormones or other substances).
A junction between two neurons where a chemical neurotransmitter diffuses across a small gap to transmit the nerve signal.
It is produced by the pancreas and causes cells to take up glucose from the blood lowering blood glucose levels.
It is produced by the pancreas and causes the liver to convert glycogen back into glucose raising blood glucose levels.
A condition where the pancreas does not produce enough insulin. It is treated with insulin injections.
A condition where body cells stop responding to insulin. It is linked to obesity and treated with diet and exercise.
Anti-diuretic hormone produced by the pituitary gland. It controls water reabsorption in the kidneys.
Follicle-stimulating hormone causes an egg to mature in the ovary and stimulates oestrogen production.
It repairs the uterus lining after menstruation and triggers a surge of LH which causes ovulation.
A double-stranded molecule made of nucleotides arranged in a double helix that carries genetic information.
A section of DNA that codes for a specific protein.
Adenine (A) thymine (T) cytosine (C) and guanine (G).
A pairs with T and C pairs with G.
A long coiled molecule of DNA found in the nucleus of a cell.
46 (23 pairs)
A dominant allele is expressed even if only one copy is present. A recessive allele is only expressed if two copies are present.
The genetic makeup of an organism (the alleles it carries).
The observable characteristics of an organism resulting from its genotype and environment.
An organism with two identical alleles for a particular gene (e.g. BB or bb).
An organism with two different alleles for a particular gene (e.g. Bb).
The process by which organisms with advantageous traits are more likely to survive reproduce and pass on their genes.
The gradual change in the inherited characteristics of a population over many generations.
When all members of a species have died and the species no longer exists.
Individual → population → community → ecosystem
A sequence showing the feeding relationships between organisms with arrows showing the direction of energy flow.
An organism (usually a plant) that makes its own food through photosynthesis forming the base of a food chain.
An organism that obtains energy by eating other organisms.
The variety of different species and the genetic variation within species in an ecosystem.
The continuous process by which carbon is recycled through living organisms and the environment via photosynthesis respiration decomposition and combustion.
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