BIOLOGY IGCSE EDEXCEL 2025
🧬 BIOLOGY DEFINITIONS – PART 1
1. What is active transport?
A. Movement of substances down a concentration gradient
B. Diffusion through a membrane without energy
C. Movement of substances against a concentration gradient using energy ✅
D. Movement of gases in the lungs
2. What does the Anti-Diuretic Hormone (ADH) control?
A. Production of red blood cells
B. Selective reabsorption of water in the kidney ✅
C. Regulation of heartbeat
D. Conversion of glycogen to glucose
3. What is aerobic respiration?
A. Breakdown of food without oxygen
B. Breakdown of food using oxygen to release energy ✅
C. Photosynthesis in the mitochondria
D. Conversion of lactic acid to glucose
4. What is an allele?
A. A protein made from amino acids
B. A version of a particular gene ✅
C. A copy of a chromosome
D. A mutation in DNA
5. What is anaerobic respiration?
A. Respiration that uses oxygen
B. Respiration that occurs in the absence of oxygen ✅
C. Respiration only in plants
D. Respiration in mitochondria only
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,6. What is asexual reproduction?
A. Reproduction with two parents
B. Reproduction involving one parent, producing identical offspring ✅
C. Fertilisation between gametes
D. Reproduction with variation
7. What are auxins?
A. Animal growth hormones
B. Plant hormones controlling phototropism ✅
C. Enzymes for photosynthesis
D. Pigments in leaves
8. What are carbohydrates?
A. Fats and oils
B. Proteins that build muscle
C. Sugars and starches that provide energy ✅
D. Hormones for growth
9. What is a cell?
A. The smallest living unit of all organisms ✅
B. A tissue that performs a function
C. A group of organ systems
D. The nucleus of an organism
10. What is cellular respiration?
A. Occurs in chloroplasts during photosynthesis
B. Respiration that takes place in cytoplasm and mitochondria ✅
C. A form of fermentation
D. The absorption of nutrients
11. What is the cellulose cell wall?
A. The outer protein coat of viruses
B. The rigid wall surrounding plant cells made of cellulose ✅
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, C. The flexible membrane of animal cells
D. A lipid barrier
12. What is chlorophyll?
A. A yellow pigment
B. The green pigment in chloroplasts that captures sunlight ✅
C. A sugar molecule in plants
D. A hormone for growth
13. What are chloroplasts?
A. Organelles that contain chlorophyll and are the site of photosynthesis ✅
B. Sites of respiration
C. Energy-storing vacuoles
D. Ribosome clusters
14. What is a clone?
A. Genetically different offspring
B. Offspring identical to parent produced by asexual reproduction ✅
C. Offspring produced sexually
D. Mutation in a gene
15. What is codominance?
A. One allele hides the other
B. Both alleles are expressed in the phenotype ✅
C. Only recessive alleles are expressed
D. Random expression of genes
16. What are consumers?
A. Organisms that make their own food
B. Organisms that feed on others for energy ✅
C. Organisms that decay dead matter
D. Producers in an ecosystem
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🧬 BIOLOGY DEFINITIONS – PART 1
1. What is active transport?
A. Movement of substances down a concentration gradient
B. Diffusion through a membrane without energy
C. Movement of substances against a concentration gradient using energy ✅
D. Movement of gases in the lungs
2. What does the Anti-Diuretic Hormone (ADH) control?
A. Production of red blood cells
B. Selective reabsorption of water in the kidney ✅
C. Regulation of heartbeat
D. Conversion of glycogen to glucose
3. What is aerobic respiration?
A. Breakdown of food without oxygen
B. Breakdown of food using oxygen to release energy ✅
C. Photosynthesis in the mitochondria
D. Conversion of lactic acid to glucose
4. What is an allele?
A. A protein made from amino acids
B. A version of a particular gene ✅
C. A copy of a chromosome
D. A mutation in DNA
5. What is anaerobic respiration?
A. Respiration that uses oxygen
B. Respiration that occurs in the absence of oxygen ✅
C. Respiration only in plants
D. Respiration in mitochondria only
1
,6. What is asexual reproduction?
A. Reproduction with two parents
B. Reproduction involving one parent, producing identical offspring ✅
C. Fertilisation between gametes
D. Reproduction with variation
7. What are auxins?
A. Animal growth hormones
B. Plant hormones controlling phototropism ✅
C. Enzymes for photosynthesis
D. Pigments in leaves
8. What are carbohydrates?
A. Fats and oils
B. Proteins that build muscle
C. Sugars and starches that provide energy ✅
D. Hormones for growth
9. What is a cell?
A. The smallest living unit of all organisms ✅
B. A tissue that performs a function
C. A group of organ systems
D. The nucleus of an organism
10. What is cellular respiration?
A. Occurs in chloroplasts during photosynthesis
B. Respiration that takes place in cytoplasm and mitochondria ✅
C. A form of fermentation
D. The absorption of nutrients
11. What is the cellulose cell wall?
A. The outer protein coat of viruses
B. The rigid wall surrounding plant cells made of cellulose ✅
2
, C. The flexible membrane of animal cells
D. A lipid barrier
12. What is chlorophyll?
A. A yellow pigment
B. The green pigment in chloroplasts that captures sunlight ✅
C. A sugar molecule in plants
D. A hormone for growth
13. What are chloroplasts?
A. Organelles that contain chlorophyll and are the site of photosynthesis ✅
B. Sites of respiration
C. Energy-storing vacuoles
D. Ribosome clusters
14. What is a clone?
A. Genetically different offspring
B. Offspring identical to parent produced by asexual reproduction ✅
C. Offspring produced sexually
D. Mutation in a gene
15. What is codominance?
A. One allele hides the other
B. Both alleles are expressed in the phenotype ✅
C. Only recessive alleles are expressed
D. Random expression of genes
16. What are consumers?
A. Organisms that make their own food
B. Organisms that feed on others for energy ✅
C. Organisms that decay dead matter
D. Producers in an ecosystem
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