B1 - GCSE

Topic 1
Key Concepts in Biology
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All living things are made of...
...cells.
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Cells can either be...
...eukaryotic or prokaryotic.
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A prokaryote is...
...a prokaryotic cell.
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What is a prokaryotic cell?
A single-celled organism.
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What are subcellular structures?
The different parts of a cell.
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Most cells are -(1)- for a particular function.
1:-specialised-
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--(1)-- contain lots of different types of cells (ie cells with different -(2)- ).
1:- Multicellular organisms-; 2:-structures-
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What are specialised cells?
Cells that have a structure which makes them adapted to their function.
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Egg cells and sperm cells are specialised for...
...reproduction.
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In sexual reproduction, the -(1)- of an egg cell -(2)- with the nucleus of a --(3)-- to create a --(4)--, which then develops into an -(5)-.
1:-nucleus-; 2:-fuses-; 3:-sperm cell-; 4:-fertilised egg-; 5:-embryo-
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Why is it important that both the nucleus of an egg cell and of a sperm cell only contain half the number of chromosomes that's in a normal body cell?
It is important as it means that when an egg and sperm nucleus fuse at fertilisation the resulting cell will have the right number of chromosmes.
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What is the function of sperm cells?
The function of a sperm is to transport the male's DNA to the female's egg.
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What is magnifictaion?
Magnification is how many times bigger the image is.
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--(1)-- are what makes you work. And -(2)- are what makes them work.
1:-chemical reactions-; 2:-enzymes-
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What is the substrate?
The substrate is the molecule changed in the reaction.
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Every enzyme has an...
...active site.
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What is the active site?
The part where the enzyme joins on to its substrate to catalyse the reaction.
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Enzymes usually only work with one substrate and are said to have...
...a high specifity for their substrate.
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It's easy to detect starch using...
...iodine solution.
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Explain the relationship/test of starch with iodine solution.
If starch is present, the iodine solution will change from browny-orange to blue-black.
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Enzymes break down big molecules. Give some examples of said big molecules.
Proteins, lipids and some carbohydrates are big molecules.
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What are lipids?
Lipids are fats and oils.
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Why is it important that organisms break down big molecules?
It's important that organisms are able to break down big molecules into their smaller components so they can be used for growth and other life processes.
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Enzymes called carbohydrases...
...convert carbohydrates into simple sugars.
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What do proteases do?
Proteases convert proteins into amino acids.
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What do lipases do?
Lipases convert lipids into glycercol and fatty acids.
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What is amylase an example of and what does it do?
Amylase is an example of a carbohydrase. It breaks down starch into maltose and other sugars.
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What happens when lipids are broken down?
When lipids are broken down, the fatty acids will lower the pH of the solution they are in.
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Some enzymes join molecules together. Glycogen synthase is an enzyme that --(1)-- lots of chains of -(2)- molecules to make -(3)- .
1:-joins together-; 2:-glucose-; 3:-glycogen-.
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What is glycogen?
Glycogen is a molecule used to store energy in animals.
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What are biological molecules?
Molecules found in living organisms.
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State three biological molecules.
Carbohydrates, proteins and lipids are all biological molecules.
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How do you test for starch?
Starch is tested for using iodine?
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How do you test for proteins?
The Biuret Test is used for proteins.
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How do you test for sugars?
You can test for sugars using Benedict's Reagent.
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How do you test for lipids?
Use the Emulsion Test for lipids.
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Food can be -(1)- to see how much -(2)- it contains.
1:-burnt-; 2:-energy-
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What is the scientific name for burning food to find out the energy content.
Calorimetry.
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In calorimetry, quite a bit of the energy in the food is ----(1)----. You can minimise this by ...
1:-transferred to thge environment-; ...insulating the boiling tube e.g. with foil.
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1cm cubed of water is the same as...
...1g of water.
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Substances can move in and out of cells by...
diffusion, osmosis, and active transport.
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Diffusion happens in both...
...liquids and agses.
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Why can diffusion happen in these substances (gases and liquids)?
Diffusion happens in both liquids and gases because the particles in these substances are free to move about (randomly).
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Only very -(1)- molecules can -(2)- through --(3)--.
1:-small-; 2:-diffuse-; 3:-cell membranes-.
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Name 4 molecules that can diffuse through cell membranes .
Glucose, amino acids, water and oxygen.
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Big molecules like -(1)- and -(2)- can't fit through the membranes.
1:-starch-; 2:-proteins-
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Osmosis is a special case of...
...diffusion.
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What is a partially permeable membrane?
A partially permeable membrane is one with very small holes in it that only tiny molecules e.g. water can pass through them, and bigger molecules (e.g. sucrose) can't.
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In osmosis, high water concentration is...
...also low solute concentratiion.
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in osmosis, low water concentration is...
... also high solute concentration.
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Active transport works...
...against a concentration gradient.
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Topic 2
Cells and Control
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Explain why cells have to be able to divide.
In order to survive and grow, cells have got to be able to divide.
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Chromosomes contain...
...genetic information.
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Most cells in your body have...
...a nucleus.
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The nucleus contains...
...your gentic material in the form of chromosomes.
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What are chromosomes?
Chromosomes are coiled up length of DNA molecules.
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--(1)-- normally have --(2)-- of each chromosome making them diploid cells.
1:-body cells-; 2:-two copies-
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One chromosome come from the organism's -(1)- and one comes from its -(2)-.
1:-'mother'-; 2:-'father'-
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Body cells in -(1)- organisms divide to produce new cells during a process called the --(2)--.
1:-multicellular-; 2:-cell cycle-
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What is mitosis?
The stage of the cell cycle when the cell divides is called mitosis.
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Multicellular organisms usew mitosis to...
...grow or to replace old and damaged cells.
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Some organisms use mitosis to -(1)-, this is called --(2)--.
1:-reproduce-; 2:-asexual reproduction-
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Growth involves...
...cell division, differentiation, and elongation.
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What is growth?
Growth is an increase in size or mass.
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Plants and animals grow and develop due to these processes...
...cell differentiation and cell division.
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Plants also grow by...
...elongation.
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What is a mutation?
A random change in a gene.
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Percentile charts are used...
...to monitor growth.
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What are growth charts for?
Growth charts are used to assess a child's growth over time, so that an overall pattern in development can be seen and any problems highlighted.
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Name possible problems that can be highlighted using a growth chart.
Obesity, malnutrition, dwarfism.
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A baby's growth is regularly monitored after birth to make sure it's growing normally. Three measurements are taken, what are they?
Length, mass and head circumference.
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Name a process that's for growth in plants but not in animals.
Cell elongation.
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Describe how a plant grows by cell elongation.
Cell elongation makes a plant's cells expand so the cells get biggerand the plant grows.
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What are stem cells?
Stem cells are undifferentiated cells.
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What can stem cells do?
Stem cells can differentaite into different types of cells.
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What makes up the CNS (Central Nervous System)?
The brain and the spinal cord make up the CNS.
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What is the spinal cord?
The spinal cord is a long column of neurones that run from the base of the brain down the spine.
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What are neurones?
Neurones are nerve cells.
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The brain is made up of...
...billions of interconnected neurones.
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Explain the function of scanners.
The brain can be visualised without surgery using scanners; scanners are used to investigate brain functions. Scanners reduce the need for rsiky surgeries.
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What is the nervous system?
The nervous system is what lets you react to what goes on around you.
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The nervous system is made up of -(1)- which go to --(2)-- of the body.
1:-neurones-; 2:-all parts-
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The body has lots of sensory receptors. What are sensory receptors?
Groups of cells that can detect a change in the environment.
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Different receptors detect different stimuli. What do receptors in your eyes detect?
Receptors in the eyes detect light.
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What do receptors in your skin detect?
Receptors in the skin detect touch(pressure) and temperature change.
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What is a stimulus?
A stimulus is a chnage in the environment.
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What is reaction time?
The time it takes you to respond to a stimulus.
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What is a synapse?
The connection/gap between two neurones is called a synapse.
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What are neurotransmitters?
Neurotransmitters are chemicals that transfer nerve siganls.
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How do neurotransmitters move/travel?
They diffuse across the gap.
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What is a reflex?
An automatic, rapid respsonse to stimuli.
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What is the aim/purpose of a reflex?
To reduce the chances of being injured.
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What is a reflex arc?
The passage of information in reflex (from receptor to effector) is called a reflex arc.
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The neurones in reflex arcs go...
...through the spinal cord or (through) an unconscious part of the brain.
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Why are reflexes quicker?
Because you don't have to spend time thinking about the response, it's quicker than normal responses.
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---(1)--- can damage the eye so you have a reflex to --(2)--.
1:-Very bright light-; 2:-protect it-
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The -(1)- is sensitive to -(2)- and responsible for sight.
1:-eye-; 2:-light-
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The -(1)- from light is converted into --(2)--.
1:-information-; 2:-electrical impulses
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The lens is -(1)-, so the eye can focus light onto the retina by ---(2)--- of the lens.
1:-elastic-; 2:-changing the shape-
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Long and short-sightedness are caused by..
...structural abnormalities.
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Long-sighted people are unable to...
...focus n near objects.
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Short-sighted people are unable to...
...focus on distant object.
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How can you correct long-sightedness?
You can use glasses or contact lenses with a convex lens.
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How can you correct short-sightedness?
You can use glasses or contact lenses with a concave lens.
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What is the most common form of colour blindness?
The most common form of the disorder is red-green colour blindness.
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What is red-green colour blindness caused by?
It's caused when red or green cones in the retina are not working properly.
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Is there a cure for colour blindness and explain why.
There's no cure for colour blindness at the moment because the cone cells can't be replaced.
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Explain what a cataract is?
A cataract is a cloudy patch on the lens, which stops light from being able to enter the eye normally.
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People with cataract are likely to have...
...blurred vision, difficulty seeing in bright light and may also experience colours looking less vivid.
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A cataract can be treated by...
...replacing the faulty lens with an artificial one.
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Topic 3
Genetics
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Sexual reproduction produces...
...genetically different cells.
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What is sexual reproduction?
Sexual reproduction is where genetic information from two organisms (a father and a mother) is combined to produce offspring which are genetically different to either parent.
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In sexual reproduction, the father and mother produce -(1)- and in animals these are -(2)- and --(3)--.
1:-gametes-; 2:-sperm-; 3:-egg cells-
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What are gametes?
Gametes are reproductive cells.
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Gametes contain...
...half the number of chromosomes of normal cells.
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What is meant by the term "normal cells"?
Cells with the full number of chromosomes.
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What is a zygote?
A fertilised egg.
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How does a zygote develop into an embryo?
by undergoing cell division (by mitosis).
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What is the diploid number for a human?
46 chromosomes.
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What is the haploid number for a human?
23 chromsomes.
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Gametes are produced by...
...mitosis.
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Meiosis is a type of...
...cell division.
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How is meiosis different to mitosis?
It's different to mitosis because it doesn't produce identical cells.
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In humans, meiosis only happens...
...in the reproductive organs.
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What are the reproductive organs in humans?
Ovaries and testies.
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The haploid gamete of a plant species has 12 chromosomes. Two of these gametes fuse to make a zygote. How many chromosomes will there be in the zygote?
24 chromosomes.
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How does meiosis introduce genetic variation?
When the cell divides, some of the chromosomes from the organism's father and mother go into each new cell. The mixing up of the chromosomes/genes creates genetic variation.
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Humans can only reproduce...
...sexually.
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Some organisms can reproduce by either...
...sexual or asexual reproduction.
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Reproducing is very important to all organisms. why?
It's how they pass on their genes.
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Explain what happens when cells divide asexually.
They divide by mitosis resulting in two diploid daughter cells, which are genetically identical to each other and to the parent cell.
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Explain sexual reproduction
It involves meiosis and the production of different haploid gametes, which fuse to form a diploid cell at fertilisation.
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What is reproduction all about?
Passing on your DNA to the next generation.
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DNA is made up of...
...nucleotides.
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DNA strands are -(1)- made up of lots of repeating units called -(2)-.
1:-polymers-; 2:-nucleotides-
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Each nucleotide consists of...
...one sugar molecule, one phosphate molecule and one 'base'.
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Explain the sugar and phosphate molecules in the nucleotides.
The sugar and phosphate molecules in the nucleotides form a 'backbone' to the DNA strands.
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What joins to each sugar?
One of four different bases joins to each sugar.
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What are the bases in DNA?
A (adenine), T (thymine), C (cytosine), G (guanine).
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A DNA molecule has ----(1)---- in the shape of a --(2)--.
1:-two strands coiled together-; 2:-double helix-
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Base A ---(1)--- with T, and (base) C ---(2)--- with G. This is called ---(3)---.
1:-always pairs up-; 2:-always pairs up-; 3:-complementary base pairing-
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Complementary base pairs are joined together by...
...weak hydrogen bonds.
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DNA is stored as -(1)- and contains -(2)-.
1:-chromosomes-; 2:-genes-
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What are chromosomes?
Chromosomes are long, coiled up molecules of DNA.
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Where are chromosomes found?
They're found in the nucleus of eukaryotic cells.
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What is a gene?
A gene is a section of DNA on a chromosome that codes for a particular protein.
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All of an organism's DNA makes up its...
...genome.
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Why is it useful to use salt when extracting DNA from fruit cells?
The salt helps the DNA stick together.
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Proteins are made by...
...reading the code in DNA.
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DNA controls...
...protein synthesis in a cell.
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What is protein synthesis?
The production of proteins.
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Proteins are made up of...
...chains of molecules called amino acids.
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Each different protein has its own particular...
...number and order of amino acids.
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What is triplet?
A code based on base triplets.
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DNA also contains...
...non-coding regions.
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Many regions of DNA are --(1)-- meaning that they --(2)-- for any --(3)--.
1:-non-coding-; 2:-don't code- 3:-amino acids-
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All of an organism's DNA, including the ---(1)--- makes up the organism's -(2)-.
1:-non-coding regions-; 2:-genome-
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Genetic variants can arise by...
...mutations.
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What is a mutation?
A mutation is a rare, random change to an organism's DNA base sequence that can be inherited.
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If a mutation happens in a gene, it produces a...
...genetic variant.
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What is a genetic variant?
A different version of the gene.
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A genetic variant may cause the activity of an enzyme to...
...increase, decrease or stop altogether.
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Genetic variants could end up changing...
...the phenotype of an organism.
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Mutations can also happen in ---(1)--- of DNA.
1:-non-coding regions-
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Explain how a gene can code for a particular protein.
The order of bases in a gene determines the order of amino acids in a protein. Each gene contains a different order of bases, which the gene can code for a particular protein.
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Explain how a genetic variant can result in a protein with a very low level of activity.
A genetic variant could alter the sequence of amino acids coded for by a gene which could affect the shape of the protein, decreasing its activity.
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Proteins are made in -(1)- stages.
1:-two-
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What are the two stages of protein synthesis?
Transcription and translation.
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Where are proteins made?
Proteins are made in the cell cytoplasm by subcellular structures called ribosomes.
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What is mRNA?
Messenger RNA is a molecule.
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Why is mRNA used in protein synthesis as against DNA?
Information for proteins come from DNA however DNA is found in the cell nucleus and is too large to move out so the molecule mRNA is used to get the information from the DNA to the ribosome in the nucleus.
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mRNA uses -(1)- instead of -(2)- as a base.
1:-uracil-; 2:-thymine-
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The base uracil still pairs with...
...adenine.
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What is RNA polymerase?
RNA polymerase is the enzyme involved in joining together RNA nucleotides to make mRNA.
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Once the -(1)- is bound to a ribosome, the -(2)- can be assembled. This stage is called -(3)-.
1:-mRNA-; 2:-protein-; 3:-translation-
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What are codons?
Codons are base triplets in mRNA.
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What is a polypeptide?
A protein.
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Gregor Mendel was an --(1)-- who trained in mathematics and --(2)--.
1:-Austrian monk-; 2:-natural history-
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On his garden plot at the monastery in the mid 19th century, Mendel noted how...
...characteristics in plants were passed on from one generation to the next.
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The results of Mendel's research were published in -(1)- and eventually became the foundation of --(2)--.
1:-1866-; 2:-modern genetics-
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What are "hereditary units"?
Genes.
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Suggest why the importance of Mendel's work wasn't realised straight away.
Scientists of the time didn't have the background knowledge to properly understand Mendel's findings because they didn't know about genes, DNA and chromosomes.
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You can use genetic diagrams to predict...
...how different characteristics will be inherited.
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What are alleles?
Alleles are different versions of the same gene.
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What genes you inherit control...
...what characteristics you develop.
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You have -(1)- versions (alleles) of --(2)-- in your body, one on --(3)-- in a pair.
1:-two-; 2:-every gene-; 3:-each chromosome-
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Define homozygous?
Having two alleles that are the same for a particular gene.
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Define heterozygous?
Having two alleles that are different for a particular gene.
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Some alleles are -(1)- and some are -(2)-.
1:-dominant-; 2:-recessive-
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Dominant alleles are shown...
...with a capital letter.
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Recessive alleles are shown...
...with a lower case letter.
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If an organism has one dominant allele and one recessive allele for a gene,...
...then the dominant allele will determine what characteristic is present.
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To display a dominant characteristic,...
....an organism can have either two dominant alleles for a particular gene or one dominant and one recessive allele for that gene.
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For an organism to display a recessive characteristic,...
...both its alleles must be recessive.
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Define genotype.
Your genotype is the combination of alleles you have.
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Define phenotype.
Your phenotype is the characteristics you have.
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What is monohybrid inheritance?
The inheritance of a single characteristic.
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A genetic diagram can show how -(1)- is determined in humans.
1:-sex-
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All eggs have one X chromosome but a sperm can have...
...either an X or Y chromosome.
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Sex determination in humans depends...
...on whether the sperm that fertilises an egg carries an X or Y chromosome.
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What is a family pedigree?
A family tree of genetic disorders.
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Some genetic characteristics are...
...sex-linked.
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A characteristic is sex-linked if...
...the allele that codes for it is located on a sex chromosome.
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What are sex-linked disorders?
Disorders caused by faulty alleles located on sex chromosomes.
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Colour blindness is a --(1)-- disorder.
1:-sex-linked-
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Colour blindness is caused...
...by a faulty allele carried on the X chromosome.
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Name another sex-linked disorder aside from colour blindness.
Haemophilia.
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There are --(1)-- that determine blood group.
1:-multiple alleles-
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Humans have -(1)- potential blood types and the gene for blood type in humans has ---(2)---.
1:-four-; 2:-three different alleles-
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Organisms of the --(1)-- will usually look slightly different; these differences are called the -(2)- within a species.
1:-same species-; 2:-variation-
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What are the two types of variation?
Genetic and environmental.
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Genetic variation within a species is caused by...
...organisms having different alleles (versions of genes) which can lead to differences in phenotype.
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Genetic variations can be caused by...
...new alleles rising through mutations.
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--(1)-- also causes genetic variation since it results in alleles being -(2)- in lots of --(3)-- in offspring.
1:Sexual reproduction-; 2:-combined-; 3:-different ways-
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Environmental variations in phenotype are also known as...
...acquired characteristics.
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Why are environmental variations also known as acquired characteristics?
Because they're characteristics that organisms acquire during their lifetimes.
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Most variation in phenotype is determined by...
...a mixture of genetic and environmental factors.
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What are mutations?
Mutations are changes to the base sequence of DNA.
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When mutations occur within a gene they result in...
...an allele, or a different version of the gene.
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Most mutations don't have any effect so in other words they are...
...neutral.
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Why does sexual reproduction in genetic variation in a population?
It results in new combinations of alleles in offspring.
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With the Human Genome Project, the big idea was...
...to find every single human gene.
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State the start, end and results of the Human Genome Project.
The project officially started in 1990 and a complete map of the human genome, including the locations of around 20,500 genes, was completed in 2003.
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The Human Genome Project has helped to identify about --(1)-- related to disease, which has huge potential -(2)- for -(3)-.
1:-1800 genes-; 2:-benefits-; 3:-medicine-
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How could information from the Human Genome Project be used to help prevent individuals from developing certain diseases?
A person's genes can be used to help predict what diseases they're most at risk of devolving. This means that they could be given lifestyle and diet advice to help prevent them from getting the diseases.
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Topic 4
Natural Selection and Genetic Modification.
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What is evolution?
Evolution is the slow and continuous change from one generation to the next.
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Charles Darwin came up with the theory of --(1)-- to explain how -(2)- occurs.
1:-natural selection-; 2:-evolution-
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Natural selection means...
..."survival of the fittest".
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Individuals in a population show --(1)-- because of differences in their -(2)-. New alleles arise through -(3)-.
1:-genetic variation-; 2:alleles-; 3:mutations-
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State the three selection pressures.
Predation, competition for resources (e.g. food, water, mates, etc) and disease.
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A species that can't compete is likely to go...
...extinct.
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What is an antibiotic?
A drug designed to kill bacteria or prevent them from reproducing.
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Why is it easy to see evolution in bacteria?
Because they reproduce so quickly.
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What is a fossil?
A fossil is any trace of an animal or plant that lived a long time ago (e.g. over a thousand years).
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Fossils are most commonly found in...
...rocks.
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Generally, the -(1)- the rock the -(2)- the fossil.
1:-deeper-; 2:-older-
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By arranging fossils in chronological order, what can be observed?
Gradual changes in organisms can be observed and this provides evidence for evolution, because it shows how species have changed and developed over billions of years.
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How do fossils provide evidence that organisms evolved from simpler life forms?
Arranging fossils in chronological order shows gradual changes/development in organisms.
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Describe Wallace's role in developing the theory of evolution by natural selection.
Wallace provided evidence for natural selection and worked with Darwin to develop the theory.
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Evidence from -(1)- suggests that humans and -(2)- evolved from a --(3)-- that existed around --(4)-- years ago.
1:-fossils-; 2:-chimpanzees-; 3:-common ancestor-; 4:-6 million-
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Human beings and their ancestors are known as...
...hominids.
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Fossils of several --(1)-- have been found; these fossils have characteristics that are -(2)- apes and humans. By looking t --(3)-- you can see how much humans have -(4)- over time.
1:-hominid species-; 2:-between-; 3:hominid fossils-; 4:evolves-
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-(1)- is a fossils hominid 4.4 million years old.
1:-'Ardi'-
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-(1)- is a fossil hominid 3.2 million years old.
1:-'Lucy'-
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--(1)-- is a fossil hominid 1.6 million years old.
1:-Turkana Boy-
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Development of --(1)-- provides evidence for human evolution.
1:-stone tools-
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What is a pentadactyl limb?
A pentadactyl limb is a limb with five digits.
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You can see the pentadactyl limb in many species, e.g....
...mammals, reptiles, amphibians.
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What is classification?
Classification is organising living organisms into groups.
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Traditionally, organisms were classified according to...
...similarities and differences in their observable characteristics. As technology improved this included things you can see with a microscope, e.g cell structure.
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What are the five kingdoms?
Animals, plants, fungi, prokaryotes, protists.
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What are Woese's three domains?
Archaea, Bacteria, Eukarya.
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Give one example of how advances in technology allowed scientists to distinguish between Archaea and Bacteria.
RNA/DNA sequencing showed that Archaea and Bacteria were less closely related than first thought.
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Give the simple definition of selective breeding.
Taking thee best best plants or animals and breeding them together to get the best possible offspring.
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Give the scientific definition of selective breeding.
When humans artificially select the plants or animals that are going to breed so that the genes for particular characteristics remain in the population.
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Organisms are --(1)-- to develop features that are -(2)- or -(3)-.
1:-selectively bred-; 2:-useful-; 3:-attractive-
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Tissue culture involves...
...taking little bits tissues and growing them on an artificial growth medium.
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The plants produced via tissue culture are -(1)- and are --(2)-- organisms.
1:-clones-; 2:-genetically identical-
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You can use tissue culture to create lines of clones all with the same beneficial features e.g. ...
...pesticide resistance, tasty fruit, etc.
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Genetic engineering involves...
...modifying an organism's genome (it's DNA)to introduce desirable characteristics.
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Genetic engineering involves the use of...
...enzymes and vectors (carriers).
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What are recombinant DNA?
Two different bits of DNA stuck together.
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What is a vector?
A vector is something that's used to transfer DNA into a cell and can be used to insert DNA into other organisms.
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There are two sorts of vectors, what are they?
Plasmids and viruses.
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Genetic engineering is useful in -(1)- and -(2)-.
1:-agriculture-; 2:-medicine-
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Explain one benefit of being able to genetically engineer herbicide-resistant crops.
It can improve the yield of the crop because herbicide-resistant crops can be sprayed with herbicides to kill weeds without the crop being damaged.
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Describe restriction enzymes.
Restriction enzymes recognise specific sequences of DNA and cut the DNA at these points; the pieces of DNA are left with sticky ends where they have been cut.
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Describe ligase enzymes.
Ligase enzymes are used to join two pieces of DNA together at their sticky ends.
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What does GMO stand for?
Genetically modified organisms.
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Suggest three methods that could be used to help provide food for a growing human population.
Use of GM crops with improved yields; use of fertilisers on poor soils; use of biological pest control methods.
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What is WHO?
The World Health Organisation.
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What is the WHO's definition of health?
A state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity.
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Infirmity means...
...weakness or frailness, commonly due to old age.
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What is disease?
A disease is a condition where part of an organism doesn't function properly.
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There are two sorts of disease. What are they?
Communicable and non-communicable.
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Describe communicable diseases?
Communicable diseases are diseases that can be spread between individuals.
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Describe non-communicable diseases?
Non-communicable diseases can't be transmitted between individuals e.g. cancer and heart disease.
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If you are affected by one disease, it could make you...
...more susceptible to others as your body may become weakened by the disease, leaving it less able to fight off others.
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Being susceptible to a disease, means...
...that you have an increased chance of getting it.
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What are pathogens?
Pathogens are organisms that cause communicable diseases and include viruses, bacteria, fungi and protists.
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What pathogen causes cholera and tuberculosis?
A bacterium.
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What pathogen causes malaria?
A protist.
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What pathogen causes stomach ulcers?
A bacterium.
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What pathogen causes chalara ash dieback?
A fungus that infects ash trees.
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What pathogen causes ebola?
A virus.
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How does cholera spread?
Via contaminated water.
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How does tuberculosis spread?
Through the air when infected individuals cough.
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How do stomach ulcers spread?
Oral transmission (e.g. swallowing contaminated water or food).
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How does ebola spread?
Via bodily fluids.
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How does chalara die ashback spread?
It's carried through the air by the wind. It also spreads when diseased ash trees are moved between areas.
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How does malaria spread?
Mosquitoes act as animal vectors (carriers), passing on the protist to humans but not getting the disease themselves.
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Viruses can only reproduce...
...inside living cells.
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Viruses aren't cells; they're usually no more than a --(1)-- around a strand of --(2)--.
1:-protein coat-; 2:-genetic material-
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Viruses have to ---(1)--- (called host cells) in order to reproduce.
1:-infect living cells-
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The --(1)-- of a virus starts with when it infects a new --(2)--.
1:-life cycle-; 2:-host cell-
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What are the two forms of reproduction for viruses.
The lytic pathway and the lysogenic pathway.
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What is the most common form of reproduction for viruses?
The lytic pathway.
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STIs are infections that are spread through...
...sexual contact, including sexual intercourse.
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Plants produce chemicals called -(1)- which kill bacterial and fungal -(2
1:-antiseptics-; 2:-pathogens-
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Plants also produce -(1)- to deter -(2)- from -(3)- on their leaves.
1:-chemicals-; 2:-pests-; 3:-feeding-
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Plant diseases can be -(1)- in the -(2)- and in the -(3)-.
1:-detected-; 2:-field-; 3:-lab-
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In the field, plant diseases are usually detected...
...by observations.
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What are plant pathologists?
Experts in plant disease.
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What are galls?
Abnormal growths.
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With plants, what might galls indicate?
Galls (abnormal growth) might indicate crown gall disease.
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Different pathogens are spread in different ways, e.g. patches of diseased plants may suggest...
...that the disease is spread through the soil.
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Different pathigens are spread in different ways, e.g. a random distribution of diseased plants may suggest...
...an airborne pathogen.
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Laboratory-based --(1)-- allows accurate -(2)- of specific pathogens.
1:-diagnostic testing-; 2:-identification-
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Laboratory-based diagnostic testing might involve --(1)-- or --(2)--.
1:-detecting antigens-; 2:-detecting DNA-
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Like plants, the human body has -(1)- and -(2)- defences against pathogens.
1:-physical-; 2:-chemical-
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These physical and chemical barriers are...
...non-specific and they work against many different types of pathogens.
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If pathogens do make it into your body, your --(1)-- kicks in to -(2)- them.
1:-immune system-; 2:-destroy-
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The most important part of your immune system is...
...the white blood cells.
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B-lymphocytes are a type of white blood cell that are involved in...
...the specific immune response.
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Memory lymphocytes give -(1)- to late infection.
1:-immunity-
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Immunisation stops you...
...getting infections.
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What are epidemics?
Big outbreaks of diseases.
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What are B-lymphocytes?
A type of white blood cell that is involved in the specific immune response and produces antibodies.
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Why is the secondary immune response to a pathogen much faster than the first respsonse?.
Memory lymphocytes are produced in response to a foreign antigen and remain in the body for a long time. So when the pathogen enters the body again, there are more cells that recognise it and can produce antibodies against it.
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Antibodies are produced by...
...B-lymphocytes, a type of white blood cell.
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Briefly explain pregnancy tests.
A hormone (HCG) is found in the urine of women only when they are pregnant, pregnancy testing sticks detect this hormone.
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What is a hybridoma cell made from?
A (mouse) B-lymphocytes and a tumour (myeloma) cell called a myeloma cell.
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What are tumour markers?
Proteins found on the cell membrane of cancer cells.
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Why is antibody-based anti-cancer drug superior to other drugs or radiotherapy?
Other cancer treatments (e.g. radiotherapy) can affect normal body cells as well as killing cancer cells so the side effects of an antibody-based drug are lower than for other drugs or radiotherapy, thus making them superior.
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Antibiotics are used to treat...
...bacterial infections.
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How do antiobiotics work?
Antiobiotics work by inhibiting processes in bacterial cells, but not in the host organism.
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Some antibiotics inhibit the building of bacterial cells, explain what this does.
This prevents the bacteria from dividing, and eventually kills them, but has no effect on cells in the human host (which don't have cell walls).
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Different antibiotics kill different types of bacteria, so it's important...
...to be treated with the right one.
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Antibiotics don't destroy viruses. Why?
Viruses reproduce using the host's body cells, which makes it very difficult to develop drugs that destroy just the virus without killimg the body's cells.
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State the difference between antibiotics and antiseptics.
Antiobiotics kill bacteria inside the body; antiseptcis kill bacteria outside the body (e.g. on the skin).
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What is an inhibition zone?
A clear area left where bacteria have died.
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The more effective the antibiotic is against the bacteria,...
...the larger the inhibition zone.
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Smoking is a major risk factor associated with...
...cardiovascular disease.
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What is cardiovascular disease?
Any disease associated with the heart or blood vessels e.g. a heart attack or stroke.
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a diet with too many or too few nutrients...
...can lead to malnutrition and diseases associated with malnutrition, e.g. scurvy.
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What is scurvy?
A vitamin C deficiency disease.
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Getting too many nutrients is also a form of -(1)-, and can lead to -(2)-.
1:-malnutrition-; 2:-obesity-
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What are risk factors for obesity?
Not getting enough exercise and having a diet high in fat and sugars.
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Drinking too much alcohol is a major risk factor for...
...the development of liver disease.
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What is cirrhosis?
Scarring of the liver.
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As well as smoking, there are lots of other risk factors associated with cardiovascular disease, including:...
...drinking too much alcohol, lack of exercise, and a diet high in saturated fat.
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Many non-communicable diseases are caused by --(1)-- rsik factors -(2)- with each other, rather than ---(3)---, including cancer, liver and lung disease and obesity.
1:-several different-; 2:-interacting-; 3:-one factor alone-
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Obesity is a risk factor for other non-communicable diseasess, e.g....
...type 2 diabetes and cardiovascular disease.
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Give examples of lifestyle factors that increase the rsik of cardiovascular disease.
Smoking;diet high in saturated fat;drinking too much alcohol;not enough exercise;obesity.
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The Body Mass Index (BMI) is used as a guide to help decide...
...whether someone is underweight, normal, overweight or obese.
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Excess aenergy is stored as...
...fat.
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BMI isn't always reliable measure of obesity. Give an example of why.
For example, athletes have lots of muscles, which weighs more than fat, so they can come out with a high BMI even though they're not overweight.
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What does CVD stand for?
Cardiovascular disease.
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