KS3 Science Biology Revision Cards


Revision cards for science (biology) at KS3 level.
Lilac Potato
Flashcards by Lilac Potato, updated more than 1 year ago
Lilac Potato
Created by Lilac Potato about 9 years ago

Resource summary

Question Answer
How is a leaf adapted to carry out photosynthesis? Thin - short distance for carbon dioxide to move by diffusion into leaf Contains chlorophyll - absorbs light Stomata - allows carbon dioxide to move by diffusion into leaf Guard cells - open & close stomata depending on conditions Network of tubes - transport water (xylem) & food (phloem)
What is the equation for respiration and photosynthesis? Respiration: glucose + oxygen → carbon dioxide + water Photosynthesis: carbon dioxide + water → glucose + oxygen
What do animal cells and plant cells both contain and what do they do? Cell membrane - controls movement of substances into & out of cell Cytoplasm - jelly-like substance, where chemical reactions happen Nucleus - carries genetic information & controls what happens inside cell Mitochondria - where most respiration reactions happen
Give 5 examples of organ systems. Circulatory system Respiratory system Digestive system Nervous system Reproductive system (for example)
What does MRS GREN stand for and what does it help remember? Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion and Nutrition. It helps to remember the 7 life processes.
When we swallow, what organs does our food pass through? Oesophagus, stomach, small intestine and large intestine
What happens at each stage of digestion? Food is digested in mouth, stomach & small intestine. Digested food is absorbed into bloodstream in small intestine. Excess water is absorbed back into body in large intestine. Any undigested food passes out of the anus as faeces when we go to toilet.
What does each letter stand for? A - Trachea B - Alveoli C - Bronchiole D - Right Bronchus E - Ribs F - Intercostal Muscles G - Diaphragm H - Heart
What can individuals of the same species do that individuals of different species usually can't? Individuals of the same species can reproduce to make more individuals of the same species. Two individuals belonging to different species cannot normally reproduce together. If they do, their offspring is usually infertile and unable to reproduce.
What is variation? The presence of differences between living things of the same species is called variation. Variation between different species is always greater than the variation within a species.
What is continuous variation? (hint below) Continuous variation is a characteristic that changes gradually over a range of values. Examples of such characteristics are: height weight foot length If you put the data into graph form, you normally get a bell shape (as shown on the other side).
What is discontinuous variation? (hint below) Discontinuous variation is when there are only a few different possibilities that a characteristic could be (categories), where there are no other possibilities and there are no values in between. The characteristic can't change (e.g. blood group).
What are the two types of variation? Inherited and environmental
What is inherited variation? Inherited variation is variation in a characteristic that is a result of genetic inheritance from the parents. e.g. eye colour and ear shape. Each egg cell and each sperm cell contains half of the genetic information needed for an individual. When these join at fertilisation a new cell is formed with all the needed genetic information.
What is environmental variation? Environmental variation is the difference in a characteristic due to the surrounding environment. e.g. weight, height, language and religion.
What is natural selection? Within each species, individuals with the variations best suited to the environment will survive better than the others. More of them will survive to reproduce than the others. When they do, they pass on the genetic information for these variations to their offspring. Species gradually evolve in this way and this is natural selection.
What is artificial selection? Artificial selection is when people use selective breeding to produce new varieties of a species. e.g. a farmer might breed only cows that produce a lot of milk.
What are the five kingdoms? Protoctists, prokaryotes, fungi, plants and animals
What are the 7 food groups and what are they needed for? Carbohydrates - to fuel the body Proteins - vital for growth and repair Fats - store of energy used if the body runs out of carbohydrates Vitamins - keep many vital processes happening Minerals: iron for blood, calcium for teeth and bones, sodium for nerves and iodine for thyroid in the neck Fibre - keeps digestive system fit and healthy Water - all chemical reactions take place in water - 75% of body is water
Describe the menstrual cycle. On day 1, bleeding starts. This is due to the lining of the uterus breaking down. By the end of about day 5, the loss of blood stops. The lining of the uterus begins to re-grow and an egg cell starts to mature in one of the ovaries. At about day 14, the mature egg cell is released from the ovary. This is called ovulation. The egg cell travels through the oviduct towards the uterus. On day 29 (day 1 again), the lining of the uterus begins to break down and the cycle repeats.
Name 5 specialised cells and state what they are designed for. 1. Sperm cell - designed to fertilise eggs 2. Egg cell - designed to be fertilised 3. Palisade cell - designed for photosynthesis 4. Cilia cell - designed to stop lung damage 5. Root hair cell - designed for absorbing
How is a polar bear adapted to arctic conditions? 1. A round shape to give minimum possible surface area to reduce heat loss from the skin 2. A thick layer of fat for insulation and a food store 3. A thick hairy coat to keep body heat in 4. Greasy fur to shed water after swimming 5. A white coat to blend into the surroundings 6. Big feet to spread the weight on the snow or ice
How is camel adapted to desert conditions? 1. It can store a lot of water - it can drink up to 20 gallons at once. 2. It loses very little water in wee or sweat 3. It can cope with big changes in temperature and doesn't sweat below 46 degrees celsius 4. Big feet to spread the weight on the soft sand. 5. All fat is stored in the hump, this helps with heat loss 6. Its sandy colour gives good camoflague
What do food chains show? Food chains show the feeding relationships between living things.
What is a carnivore? An animal which only eats animals and never plants.
What is an omnivore? An animal which eats both plants and animals.
What is a herbivore? An anima which only eats plants.
What are food webs? Food webs are systems of interlocking and interdependent food chains.
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