GCSE Biology Revision Flashcards

Flashcards for GCSE Biology Year 10 Revision

What is the function of the nucleus?

Contains DNA to control cell function

What is the function of the cell membrane?

Controls which substances enter and leave the cell

What happens in the cytoplasm?

Chemical reactions take place

What is the function of the vacuole?

Contains cell sap to help make the cell firm

What is the function of the cell wall?

Made of cellulose to make the cell rigid

What happens in the chloroplast?

Carries out photosynthesis to make food

What happens in the mitochondria?

Carries out aerobic respiration to release energy from glucose

How do you calculate overall magnification when using a microscope?

Eyepiece lens x Objective lens

Why is a stain added when preparing a slide of onion tissue or human cheek cells?

To make the cell parts more visible

What is the function of a red blood cell?

Does not have a nucleus to allow more space to carry oxygen. Biconcave disc shape for a large surface area to absorb as much oxygen as possible.

What adaption does a palisade cell have for efficient photosynthesis?

Contains many chloroplasts containing chlorophyll to absorb the sun's energy for photosynthesis. Large vacuole to push chloroplasts to the edge of the cell to absorb more light.

What do ciliated cells do?

Contain fine hair-like structures called cilia that waft/beat mucus containing dust and bacteria away from the lungs.

What is the main adaptation of a root hair cell?

Has a large surface area to allow the greater uptake of water and minerals into the cell.

What is the function of a sperm cell?

Contains half the genetic information needed to create a baby. Has a tail to allow it to swim towards the egg. Has enzymes on its head that digest the outer layer of the egg during fertilisation.

List the levels of organisation in a multicellular organism.

Cell -> Tissue -> Organ -> Organ System -> Organism

What are Enzymes?

Biological catalysts made of protein.

What is the active site of an enzyme?

A special shaped part where the reactants fit.

What is a substrate?

The reactant molecule involved in a reaction that matches the shape of the active site.

What happens when an enzyme is denatured?

The enzyme changes shape and will no longer work.

Why is a control experiment important when testing an enzyme?

To prove that the enzyme was responsible for any results seen.

Define diffusion.

The movement of molecules from an area of high concentration to an area of low concentration.

Is energy required for diffusion?

No, it is a passive process.

Define osmosis

The movement of water molecules from an area of high water concentration to an area of low water concentration through a semi-permeable membrane.

Is energy required for osmosis?

No, it is passive.

What happens to an animal cell in pure water?

Water molecules will move into the cell, causing it to burst.

What happens to an animal cell in a strong salt solution?

Water molecules move out of the cell, causing it to shrink.

What is an isotonic solution?

A solution with the same water concentration as the cytoplasm, so there is no net movement of water.

What is respiration?

A chemical reaction that releases energy from glucose.

Where does aerobic respiration occur?

Mitochondria

Where does anaerobic respiration occur?

Cytoplasm

What are the products of aerobic respiration?

Carbon dioxide, water, and ATP (energy)

What are the products of anaerobic respiration in animals?

Lactic acid and ATP (energy)

Why does breathing rate remain high after exercise?

To repay the oxygen debt by breaking down the lactic acid.

What is the purpose of soaking peas in disinfectant during the respiration experiment?

To kill bacteria that would otherwise respire and release heat.

Name the parts of the human respiratory system

Nasal cavity/Mouth, trachea, bronchi, bronchioles, alveoli

How are alveoli adapted for efficient gas exchange?

Thin alveolar walls (one cell thick), moist lining, rich blood supply, folded shape (large surface area)

What is the function of goblet cells?

Produce and secrete sticky mucus to trap bacteria and dust

What is the function of cilia?

Beat/waft the mucus upwards away from the lungs.

What are the harmful chemicals found in cigarette smoke?

Carcinogens, tar, nicotine, carbon monoxide

What is emphysema?

Damage to the alveoli causing them to lose their specialised shape and surface area decreases.

Why is digestion important?

To turn large, insoluble molecules into small, soluble ones that can be absorbed into the bloodstream and enter cells.

What is the function of amylase?

Breaks down starch into glucose.

What is the function of protease?

Breaks down proteins into amino acids.

What is the function of lipase?

Breaks down fats (lipids) into glycerol and fatty acids.

Name the three processes involved in digestion.

Digestion, Absorption, Egestion

What is peristalsis?

Muscles behind the food contract and those in front of the food relax, pushing food along to the stomach.

What does the liver produce?

Bile

Why is bile important?

Bile is alkaline to provide the optimum pH for intestinal enzymes.

What adaptations does the small intestine have for absorption?

It is very long with many villi to increase surface area and the wall is very thin (only one cell thick).

What are some nutrients required by the human body?

Glucose, Fatty acids and glycerol, Amino acids, Minerals, Vitamins, Water, Fibre

What factors affect the rate of uptake of molecules by active transport?

Temperature, pH, glucose concentration, oxygen concentration and respiratory inhibitors such as poisons like cyanide.

What is the function of the circulatory system?

To transport substances around the body.

The heart is responsible for?

Muscular pump which contracts to push the blood around the body.

List factors that increase the risk of CVD

Smoking, High blood pressure, High blood cholesterol, Genetic factors, Lack of exercise, High levels of salt and fat in diet

What is one advantage of statins?

Reduce the likelihood that someone will suffer from a heart attack.

What is one disadvantage of statins?

Some people experience side effects such as muscle pain, liver damage and increased chance of developing diabetes type 2.

What is one advantage of angioplasty?

Improved blood flow in coronary arteries reduces the chance of a heart attack and reduces the symptoms of angina.

What is one disadvantage of angioplasty?

Sometimes blood vessels are damaged during the operation and sometimes the effects are only temporary.

What is one advantage of lifestyle changes for CVD?

Side effects from prescription drugs are avoided and there is no need for an operation which always carries some risk.

What is one disadvantage of lifestyle changes for CVD?

A very high level of self- discipline is needed to maintain long-term life-style changes.

What is photosynthesis?

A chemical reaction carried out by the leaves of a plant to make food (glucose).

What substances are needed for photosynthesis?

Carbon dioxide, Water, Light energy

Where does most photosynthesis take place in a plant?

Palisade cells

When are the stomata open?

During the day

When are the stomata closed?

During the night

How do we destarch a plant?

Keep the plant in the dark for 48 hours before the experiment. The plant cannot photosynthesise so uses up its starch stores.

What is the point in boiling a leaf in ethanol when testing for starch?

Decolourises the leaf as chlorophyll is removed – allows the colour change to be seen more easily.

What happens if we discover starch present in the leaf?

Yellow/brown -> Blue-black

What is the role of nitrogen fixing bacteria?

Convert nitrogen gas from the atmosphere to nitrates in the soil.

What is the role of denitrifying bacteria?

Turn nitrates back into nitrogen gas.

Why is intensive farming good?

A high yield is achievable in conditions that are easy to control so the food is cheaper to produce and more profitable for the farmer.

Why is intensive farming bad?

The chemicals used cause pollution and harm wildlife as well as pests.

What is a pollutant?

Something that has been added to the environment and damages it in some way.

What is an indicator species?

Organisms that can tolerate certain levels of pollution in their habitat.

Name one example of bioaccumulation

Each thrush eats two worms so receives six doses of pesticide, each worm eats two thurshes so receives twelve doses of pesticide.

Eutrophication

Fertiliser is added to farmland to add minerals to the soil and increase crop yield.

When it rains, the fertiliser leaches into rivers and lakes.

This causes algal bloom to form, which blocks the light from getting underneath.

Due to this plants underneath get no light so cannot produce food and die.

Bacteria feed on the dead plants (decay). The amount of dead plants and therefore “food“ causes them to multiply rapidly.

The large numbers of bacteria carry out lots of respiration.

This removes oxygen from the water causing aquatic insects, fish etc to suffocate and die.