Edexcel IGCSE biology- Revision
Questions All Answered Correctly
2025-2026 Updated.
What is meant by the term organ - Answer tissue(s) that carry out (same) function / different
cell types that carry out (same) function / eq;
Describe the two chemical tests someone could use to identify each type of carbohydrate,
starch and glucose - Answer 1. iodine; 2. Brownie orange to blue black color- starch 3.
Benedict's / eq; 4. heat / use water bath / eq; 5. Blue to brick red = glucose
Molecule used to store carbohydrate in animals - Answer Glycogen
Molecule used to store carbohydrate in plants - Answer Starch
Molecule used to store carbohydrates in fungi - Answer Glycogen
Describe the role of the liver in digestion - Answer bile; emulsifies / large drops to small
drops / eq; neutralize / optimum pH / alkaline;
Describe the process of digestion in the mouth (3) - Answer 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 - Answer digested / broken down; amino acids / (poly)peptides;
stomach; protease / named protease enzyme (ONCE); HCl / acid / low pH / eq; small intestine /
duodenum / ileum; bile / neutralize /alkaline / eq; optimum pH (ONCE)
Name the chemical used to test for starch - Answer Iodine
Explain what happens in a leaf when it is destarched - Answer starch removed / starch used /
no starch / eq; (converted to) glucose; respiration / energy
Describe how food is moved through the gut - Answer peristalsis; contraction; muscles;
pushed / squeezed / waves / eq
,Explain how egestion differs from excretion - Answer 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) - Answer 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 - Answer digested / broken down
amylase / carbohydrase
maltose / glucose / sugar
Describe and explain how the structure of the small intestine is adapted for absorbing digested
food. - Answer 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. - Answer 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. - Answer 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 - Answer removal of undigested food / faeces / waste from anus
Description of digestion - Answer 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. - Answer 1. soluble / dissolves; 2. osmotic effect / eq;
Give three ways in which villi are adapted to absorb small food molecules. - Answer 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 - Answer Glycogen
Molecule used to store carbohydrates in plants - Answer Starch
Molecule used to store carbohydrates in fungi - Answer 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. - Answer Denatured
Describe how the growth hormone could be destroyed in the stomach - Answer 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 - Answer 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 - Answer 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 - Answer
more osmosis / faster (small cubes) / greater % increase / greater % change / eq; larger SA:Vol
ratio (of small cubes)
What is meant by the term diffusion - Answer 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 - Answer energy / ATP; swim / move / move tail / travel
Questions All Answered Correctly
2025-2026 Updated.
What is meant by the term organ - Answer tissue(s) that carry out (same) function / different
cell types that carry out (same) function / eq;
Describe the two chemical tests someone could use to identify each type of carbohydrate,
starch and glucose - Answer 1. iodine; 2. Brownie orange to blue black color- starch 3.
Benedict's / eq; 4. heat / use water bath / eq; 5. Blue to brick red = glucose
Molecule used to store carbohydrate in animals - Answer Glycogen
Molecule used to store carbohydrate in plants - Answer Starch
Molecule used to store carbohydrates in fungi - Answer Glycogen
Describe the role of the liver in digestion - Answer bile; emulsifies / large drops to small
drops / eq; neutralize / optimum pH / alkaline;
Describe the process of digestion in the mouth (3) - Answer 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 - Answer digested / broken down; amino acids / (poly)peptides;
stomach; protease / named protease enzyme (ONCE); HCl / acid / low pH / eq; small intestine /
duodenum / ileum; bile / neutralize /alkaline / eq; optimum pH (ONCE)
Name the chemical used to test for starch - Answer Iodine
Explain what happens in a leaf when it is destarched - Answer starch removed / starch used /
no starch / eq; (converted to) glucose; respiration / energy
Describe how food is moved through the gut - Answer peristalsis; contraction; muscles;
pushed / squeezed / waves / eq
,Explain how egestion differs from excretion - Answer 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) - Answer 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 - Answer digested / broken down
amylase / carbohydrase
maltose / glucose / sugar
Describe and explain how the structure of the small intestine is adapted for absorbing digested
food. - Answer 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. - Answer 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. - Answer 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 - Answer removal of undigested food / faeces / waste from anus
Description of digestion - Answer 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. - Answer 1. soluble / dissolves; 2. osmotic effect / eq;
Give three ways in which villi are adapted to absorb small food molecules. - Answer 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 - Answer Glycogen
Molecule used to store carbohydrates in plants - Answer Starch
Molecule used to store carbohydrates in fungi - Answer 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. - Answer Denatured
Describe how the growth hormone could be destroyed in the stomach - Answer 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 - Answer 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 - Answer 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 - Answer
more osmosis / faster (small cubes) / greater % increase / greater % change / eq; larger SA:Vol
ratio (of small cubes)
What is meant by the term diffusion - Answer 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 - Answer energy / ATP; swim / move / move tail / travel
