Biology past paper questions

What is meant by the term organ

tissue(s) that carry out (same) function / different cell types that carry out (same) function / eq;

Descibe the two chemical tests someone could use to identify each type of carbohydrate, starch and glucose

1. iodine; 2. Browny orange to blue black colour- starch 3. Benedict's / eq; 4. heat / use water bath / eq; 5. Blue to brick red = glucose

Molecule used to store carbohydrate in animals

Glycogen

Molecule used to store carbohydrate in plants

Starch

Molecule used to store carbohydrates in fungi

Glycogen

Describe the role of the liver in digestion

bile; emulsifies / large drops to small drops / eq; neutralise / optimum pH / alkaline;

Describe the process of digestion in the mouth (3)

1. Amylase produced

2. Starch digested

3. Maltose / glucose

4. Physical digestion / mechanical digestion / chewing...

Fish are a good source of protein in the human diet. Describe what happens to fish protein in the gut of a human

digested / broken down; amino acids / (poly)peptides; stomach; protease / named protease enzyme (ONCE); HCl / acid / low pH / eq; small intestine / duodenum / ileum; bile / neutralise /alkaline / eq; optimum pH (ONCE)

Name the chemical used to test for starch

Iodine

Explain what happens in a leaf when it is destarched

starch removed / starch used / no starch / eq; (converted to) glucose; respiration / energy

Describe how food is moved through the gut

peristalsis; contraction; muscles; pushed / squeezed / waves / eq

Explain how egestion differs from excretion

faeces versus named excretory product; undigested food versus metabolic waste product; anus versus kidney/lung/skin; not in cells versus in cells

Explain what is meant by the term saprotrophic nutrition (2)

1 (feed on) dead / rotting / decomposing / eq;

2 enzyme(s); 3 extracellular / outside / external / eq; 4 digests / digestion / digestive; 5 absorption

Suggest what happens to starch in the gut of a parakeet

digested / broken down

amylase / carbohydrase

maltose / glucose / sugar

Describe and explain how the structure of the small intestine is adapted for absorbing digested food.

1. long; 2. villi / villus / microvilli; 3. increase surface area / eq; 4. diffusion / active transport / osmosis; 5. capillaries; 6. (blood flow) maintains concentration gradient / maintains diffusion gradient; 7. thin walls / one cell thick / short distance; (applies to villi or capillaries) 8. lacteal(s);

Suggest the consequences of having a diet that lacks fresh fruit and fibre.

1. lack vitamin C / antioxidant / scurvy / bleeding gums / eq; 2. constipation / less food movement / bowel cancer / raised cholesterol / increase heart disease / eq

Suggest the consequences of having a diet that contains too much fat.

1. obesity / increase in weight / eq; 2. blockage of arteries; 3. high blood pressure / stroke / heart disease / raised cholesterol / eq; 4. diabetes; 5. joint damage / arthritis / eq; 6. gall stones

Description of egestion

removal of undigested food / faeces / waste from anus

Description of digestion

break down large molecules / large molecules to small molecules / insoluble to soluble molecules;

Cells do not store glucose. Instead it is converted into glycogen to be stored. Suggest why cells do not store glucose.

1. soluble / dissolves; 2. osmotic effect / eq;

Give three ways in which villi are adapted to absorb small food molecules.

1. large surface area / microvilli; 2. thin / short diffusion distance / eq; 3. blood / capillaries / eq; 4. permeable; 5. lacteal;

Molecule used to store carbohydrates in animals

Glycogen

Molecule used to store carbohydrates in plants

Starch

Molecule used to store carbohydrates in fungi

Glycogen

Growth hormone is a protein. It might be present in the milk produced by the cows and then be consumed by humans. Some people are worried that this may harm humans. Other people say that this is not a problem for two reasons. Firstly, the milk is pasteurised (heated to high temperatures). Secondly, the growth hormone is destroyed in the human stomach. (i) Suggest what happens to the growth hormone when milk is pasteurised.

Denatured

Describe how the growth hormone could be destroyed in the stomach

1. HCl / hydrochloric acid; 2. enzyme / protease / pepsin

3. Breakdown/ digest 4. (acid) denatures growth hormone

Explain how the villi are adapted to absorb glucose

1. large surface area;

2. microvilli ; 3. capillaries; 4. movement of blood / concentration gradient / eq;

5. one cell thick / thin wall / thin / short distance;

6. diffusion; 7. active transport;

John wanted to investigate the effect of the size of potato tissue on the rate of osmosis. He cut three different sized cubes of potato, one 0.5 × 0.5 x 0.5 cm, one 1 × 1 × 1 cm and one 2 × 2 × 2 cm. He weighed the potato cubes and recorded their masses. He then placed each cube into a beaker of distilled water and left them for 1 hour. He weighed them again and recorded their new masses. In each case the mass of the potato cubes increased.

Use your knowledge of osmosis to explain why the

water enters / water in / eq; dilute to more concentrated solution / eq; partially permeable membrane / eq;

Explain the effect of the different SA:Vol ratios on the rate of osmosis into the potato

more osmosis / faster (small cubes) / greater % increase / greater % change / eq; larger SA:Vol ratio (of small cubes)

What is meant by the term diffusion

movement of molecules/particles/gases/named molecule; high conc. to low conc. / down concentration gradient / eq;

Respiration takes place in the middle piece of the sperm cell. Explain why respiration is important to a sperm cell

energy / ATP; swim / move / move tail / travel

What is meant by the term osmosis

1. water; 2. dilute solution to concentrated solution / high conc. (of water) to low conc. (of water) / eq; 3. selectively permeable membrane / eq;

Explain why the cells in distilled water look different when compared to the cells in salt solution.

(in distilled water) 1. water into cells; 2. outside solution/distilled water more dilute / down concentration gradient / eq; 3. cell membrane against cell wall / eq; 4. turgid; (allow converse in salt solution for each point) 1. water leaves cell; 2. outside solution/distilled water less concentrated / eq; 3. cell membrane shrinks away from cell wall /eq 4. plasmolysed / flaccid;

If red blood cells are placed in distilled water and examined under a microscope no cells are seen. Explain why no red blood cells would be seen.

1. water into red blood cell / eq;

2. cells burst / haemolysis / eq;

3. no cell wall;

What is meant by the term anaerobic?

No oxygen

Write the word equation for the anaerobic respiration of yeast

Glucose = carbon dioxide + ethanol

Give an example of a way that plants can reproduce asexually

runners / corms / bulbs / tubers / rhizomes

Suggest why the number and size of human male gametes differs from the number and size of human female gametes

1. indication of number and size difference; eg .more sperm + smaller / less eggs + larger / more sperm + larger egg / less eggs + smaller sperm 2. sperm: better chance of fertilisation / swim easier / eq egg: more cytoplasm / more nutrition / eq;

Describe the features of an insect pollinated flower that help it to attract insects

1. large (petals); 2. coloured / bright / white (petals) / eq; 3. scent / smell; 4. nectar / nectary;

Suggest why a flower grower may want his coloured flowers to reproduce asexually

1. same colour / no colour variation / same phenotype / look the same / all identical / same characteristics / eq; 2. no genetic variation / clones / alleles the same;

3. quicker production; 4. production all year round;

Suggest why insects rarely visit wind-pollinated flowers.

1. no nectar / no nectary; 2. no scent / no smell; 3. no colour / not bright / eq;

Suggest why hay fever tends to be caused by wind-pollinated plants rather than insect pollinated plants.

1. more pollen; 2. lighter pollen / smaller pollen / eq; 3. pollen is airborne / eq;

Explain the benefit to the plant of producing offspring by sexual reproduction rather than by asexual reproduction.

1. variation / diversity / different; 2. of alleles / genes; 3. better chance of survival / not all killed by disease / eq;

Give the term used to describe the fusion of gametes

Fertilisation

Name the gametes produced by females in sexual reproduction.

Eggs/ovum/ova

In which organ of a female parent do offspring develop?

Uterus / womb

Name the gametes produced by males in sexual reproduction.

Sperm

A couple want to control their fertility. The man has an operation to cut his sperm duct Explain how this operation would prevent his partner from becoming pregnant.

1. Prevent sperm leaving penis

2. No fertilisation

Suggest why the operation to cut the sperm duct in males is much more common than the operation to cut the oviducts in females.

1. testes outside / ovaries inside

2. can use local anaesthetic / no major surgery / less risk/ safer / less invasive/does not affect other organs/ eq

3. possible to reverse

The testes produce a hormone. Name the hormone and describe its functions

1. Testosterone

2. Sperm development

3. Secondary sexual characteristics

4. Sex drive/aggresion

State three ways in which the structure of insect-pollinated flowers differs from the structure of wind-pollinated flowers.

1. larger (petals);

2. colour; 3. enclosed anther / enclosed stamens / shorter stamen / shorter filament;

4. Enclosed stigma

5. Nectary

An insect carrying pollen lands on the flower. Describe the events that lead to seed formation

1. stigma; 2. pollen tube grows (down style); 3. into ovule / ovary;

4. enters via micropyle; 5. (male) nucleus / (pollen grain) nucleus / male gamete; 6. fertilisation / fuse / join / eq; 7. ovum / egg / (female) nucleus / female gamete

8. ovule becomes seed

9. ovary wall becomes seed coat

10. ovary becomes fruit

Explain the methods used to produce large numbers of fish in a fish farm (6)

1. control intraspecific predation / control overcrowding / separate sizes / separate ages / eq; 2. control interspecific predation / killing predators; 3. control disease / infection; antibiotics / remove dead fish; 3. biological control of pests / eq; 4. control oxygen; 5. remove waste products; 6. frequent feeding / feed small amounts; 7. (high) protein diet; 8. selective breeding / eq; hormones;

John wanted to investigate the effect of temperature on the rate of carbon dioxide production by yeast.

The oil layer prevents the entry of air into the glucose solution. Explain why this is necessary.

keep out oxygen; anaerobic / prevent aerobic idea / eq;

Yeast is used to produce beer. Write the word equation for the respiration of yeast that occurs during the production of beer

glucose → ethanol/alcohol + carbon dioxide;

Crop plants are often grown in glasshouses where conditions can be carefully controlled. This is done in order to get the greatest crop yield. Explain how the following factors could affect crop yield.

1. Increasing the temperature of the glasshouse

enzymes; kinetic energy / more collisions / molecules move faster / eq; (more) photosynthesis; (more) carbohydrate / glucose / eq; energy / respiration

Crop plants are often grown in glasshouses where conditions can be carefully controlled. This is done in order to get the greatest crop yield. Explain how the following factors could affect crop yield.

2. Providing a supply of fertiliser to the crop plants

minerals / ions / salts / nutrients / eq; named mineral 1; function of named mineral 1; named mineral 2; function of named mineral 2;

Eg- nitrate (ignore nitrogen) /ammonium for; amino acids / protein; if nitrogen ignored still allow function mark

Describe one example of the use of biological control

ladybird / eq; aphid / eq;

Give three advantages of using biological control instead of a chemical pesticide

1. lasts longer / no need to reapply / eq;

2. specific / no harm to other species;

3. no bioaccumulation /

no biomagnification / eq;

4. no resistance; ignore immunity 5. no harm/affect to food chain(s) / eq;

Suggest how the students should maintain the water quality in their pond

1. (more) oxygen / prevent stagnation / eq ; bubbling / paddles / pump / eq;

add water plants

2. remove waste / remove faeces / remove dead fish / remove leaves

3. prevent eutrophication / don't fertilise nearby fields / prevent algal growth

Suggest how the students could control predation in their pond

separate species / type / sizes / ages / eq; cover / net / fence / cage

scarecrow / shoot predators / shoot birds

Suggest how the students could control disease in their pond

antibiotics

fungicide;

(kill) bacteria / fungi;

remove dead fish / remove diseased fish / eq; reduce numbers / do not overcrowd / eq;

use resistant strains / eq;

keep out wild fish / eq

Explain how the removal of fish waste helps to maintain water quality

(maintain) oxygen;

(less) decomposition / respiration; bacteria / fungi / microbes / eq;

Explain how adding antibiotics would also help to maintain water quality

Less algae growth or eutrophication

kill/less bacteria / pathogens / microbes / eq; (less) disease / infection

Describe how the fish waste helps the plants to grow

bacteria / fungi / microbes / eq;

decompose(rs) / decay / rot / breakdown / eq;

mineral ions / nutrients / named mineral ion / nitrate / eq; amino acids / proteins;

respiration (by bacteria);

carbon dioxide;

photosynthesis;

Suggest what could be done on this fish farm to prevent interspecific predation

separate species / nets / cages / fences / shooting

Farmers sometimes use pesticides to prevent flies attacking sheep. Give two problems with the use of chemical pesticides.

1. kills/harms other organisms / not specific / eq;

2. affect food chain / bioaccumulation / eq;

3. resistance;

Describe a test you could use to identify the gas produced when yeast respires anaerobically

limewater;

(clear to) cloudy / (clear to) milky / eq;

or

hydrogen carbonate indicator; (orange to) yellow / eq;

A freshwater fish farmer noticed the following problems. Suggest the cause of each problem and a solution for the farmer.

i. Increase in the number of bird predators in the area

1. (attracted by) fish / food / prey / eq;

2. use nets / use cage / shoot predators / scarecrows / cover tanks / eq

A freshwater fish farmer noticed the following problems. Suggest the cause of each problem and a solution for the farmer.

ii. An increase in the growth of algae on the surface of the fish ponds

1. fish waste / faeces / urine / urea / sewage / uneaten food;

2. fertiliser / leaching / run off;

3. nitrate / ammonia / minerals / nutrients / eq;

And

5. remove waste / faeces / clean water / filter water / pump water / remove algae / use organisms that eat algae / eq;

6. reduce use of fertiliser;

7. feed little / do not overfeed

A freshwater fish farmer noticed the following problems. Suggest the cause of each problem and a solution for the farmer.

iii. An increase in the number of fish with a disease

1. bacteria / fungi / virus / pathogen / parasite / microorganisms;

2. overcrowding / infected wild fish / eq; 3. lack of genetic variation / eq

And

3. antibiotic / fungicide / pesticide /

use biological control / vaccination / eq;

4. remove infected fish / remove diseased fish / eq;

5. selective breeding of resistant fish / increase genetic diversity

Suggest two advantages of fish farming compared to catching fish in the wild.

1. (fish type) can select species / strain / size / selective breeding / eq;

2. (yield) certain catch / easy to catch /

all year yield / produce large numbers eq;

3. (environment) reduce overfishing / protect wild stocks / sustainable yield / no food chain disruption /

less chance of catching rare species / eq;

4. (safety) less risk to fishermen;

The ducks help rice plants to grow because they eat insects and weeds in the paddy fields.

(a) (i) Suggest how the ducks eating insects helps rice plants to grow.

insects eat the crop / prevent insects eating rice / rice not eaten by insects / / biological control / eq;

The ducks help rice plants to grow because they eat insects and weeds in the paddy fields.

Explain how the ducks eating weeds helps rice plants to grow.

1. (less) competition / (more) photosynthesis;

2. mineral ions / named mineral ion / nutrients / light;

Explain why faeces from the ducks helps rice plants to grow.

1. decomposed / broken down / digested;

2. bacteria / microorganisms / fungi / eq;

3. mineral ions / named mineral ion / ions / nutrients / fertiliser;

The ducks stir up the soil in the rice paddy field with their feet, which increases the oxygen content of the soil.

Suggest how increasing the oxygen content of the soil helps rice plants to grow.

1. respiration / energy / ATP;

2. active transport / active uptake;

3. of mineral ions / named mineral ions / nutrients;

Suggest what is meant by the term herbicide

kills weeds / kills unwanted plants / kills unwanted herbs / prevent growth of weeds;

Give three advantages of using biological control rather than using pesticide.

1. lasts longer / eq;

2. no reapplication / no need to keep buying pesticide / eq; 3. specific / eq;

4. avoids bioaccumulation / builds up in food chains / eq; 5. no development of resistance;

After the beer is made it is put into sterile bottles. Describe how the bottles can be sterilised.

steam / radiation / high temperature / disinfectant / ethanol / washed in hot water

Why is it important to use sterile bottles?

remove pathogens / bacteria / microorganisms / eq

The food source for the yeast cells comes from barley grains that are allowed to germinate.

Name the enzyme that digests the starch in the barley.

Amylase / maltase

The food source for the yeast cells comes from barley grains that are allowed to germinate.

Name the substance produced when the starch is digested

Maltose / glucose

During the production of beer the number of live yeast cells initially increases, but then decreases towards the end of the process.

Explain why the number of live yeast cells decreases towards the end of the process.

1. Less glucose

2. Increase in ethanol

Some athletes preparing for a long distance race train at high altitude for several weeks. The availability of oxygen at high altitude is lower so the body responds by increasing the number of red blood cells. The number of red blood cells remains high when the athletes return to lower altitude to compete.

Explain how having more red blood cells is an advantage to athletes who take part in long distance races. (4)

more oxygen; haemoglobin;

muscles;

respiration;

(less) anaerobic respiration;

(less) lactic acid / (less) oxygen debt /(less) fatigue / (less) cramp;

more energy;

run faster / run longer / run further / less tired / eq;

The tick feeds on deer by sucking their blood.

Name two different molecules that are found in the blood of deer that the tick could feed on

carbohydrate / glucose;

protein / amino acids;

fat / fatty acids / glycerol / cholesterol/ lipid; mineral / ions / salt / named mineral / named ion / named salt;

vitamin / named vitamin;

water;

Give three ways in which the structure of an artery differs from the structure of a vein

thick(er) wall;

more elastic (tissue);

more muscle (tissue);

smaller lumen / hole / less space / less single layer of cells / eq

no valves

Suggest why blood flow in a leg vein is slow when there is lack of movement

less/no) muscle(s); contraction;

squeeze vein / push blood

Name the blood cells responsible for transporting oxygen

Red blood cells

Suggest why a clot that blocks the small blood vessels in the lungs can cause death

(less/no) oxygen / oxygenated blood; heart / brain / organ / body / cells / tissues / eq;

respiration / respire / respiring

Give one way that the structure of a phagocyte differs from a red blood cell.

nucleus / bigger / irregular / not (bi)concave / eq / no haemoglobin

Describe how white blood cells are used by the body to defend against infection

1 ingest / engulf / surround / phagocytosis / eq; 2 enzymes;

3 digest / breakdown / eq;

4 lymphocytes;

5 antibodies / antitoxins;

6 specific / eq;

7 antigen:

8 memory / memory cell / eq;

Describe an experiment you could carry out to investigate the effect of exercise on breathing in humans (4)

1 rest and exercise / range of exercise / jog and run / eq

2 (how) count breaths / how many breaths / amount of breaths / volume / eq

3 for time / seconds / minutes / eq

4 quantification of exercise / jog for 5 minutes / do 10 press ups

5 repeat (for reliability

Describe how the levels of blood glucose are kept constant in human plasma after eating a meal.

pancreas / Islets of Langerhans / eq;

insulin;

lower levels; glycogen;

What is meant by the term gas exchange?

correct reference to oxygen + carbon dioxide;

Fish use their gills as a gas exchange surface.

Suggest three ways in which fish gills are adapted for efficient gas exchange.

1. large (surface) area;

2. thin / eq;

3. blood supply / capillaries; 4. permeable;

Allergies are caused by the body cells reacting to the proteins on the surface of the pollen grains.

Explain how the body usually responds to foreign proteins.

1. white blood cells / phagocytes / lymphocytes; 2. ingest / digest / phagocytosis / eq;

3. antibodies / antitoxins;

4. antigens;

5. memory cells;

What is meant by the term mutation?

1. rare / random;

2. change / damage / eq;

3. DNA / gene / allele / genetic code / eq;

Use the diagram to suggest and explain the effect of emphysema on gas exchange.

1. less surface area;

2. slower diffusion / less diffusion / less gas exchange; 3. less oxygen / less carbon dioxide;

Smoking can increase the risk of developing coronary heart disease. Explain how coronary heart disease can cause death.

1. blocked / narrowed / clogged / eq; 2. coronary artery;

3. clot;

4. fat / cholesterol;

5. less blood to heart;

6. less oxygen / less oxygenated;

7. muscle (cells);

8. less respiration / anaerobic respiration;

9. lactic acid / angina;

10. heart attack / heart stops / cardiac arrest / eq;

Suggest why a long distance athlete who trains at high altitude may have a better chance of winning than a long distance athlete who trains at sea level.

1. more haemoglobin / more red blood cells; 2. (more) oxygen;

3. (more) respiration;

4. (more) energy / (more) ATP;

5. less lactic acid / oxygen debt / less anaerobic respiration;