Biology • Year 12 • Module 5 • Lesson 12
Proteins, Phenotype and Gene-Environment Interaction
Lock in the protein categories, the genotype → protein → biological effect → phenotype pathway, and the role of environment in shaping phenotypic expression.
1. Label the genotype-to-phenotype flow
The diagram below shows the lesson's central pathway from genotype to phenotype, with environment shown as an additional influence. Write the missing labels into boxes A–H. Each label is drawn from the lesson's Key Terms or from Cards 1–5. 8 marks
- A — stage name (allele combination of the organism) _______________________
- B — what genotype encodes (information for ___ production) _______________________
- C — stage name (chain of amino acids folded into a shape) _______________________
- D — why shape matters (function depends on ___) _______________________
- E — stage name (effect on cell or organism function) _______________________
- F — stage name (observable characteristics) _______________________
- G — influence shown by the red dashed arrow _______________________
- H — worked example of G influencing F from the lesson _______________________
| Box | Your label |
|---|---|
| A | |
| B | |
| C | |
| D | |
| E | |
| F | |
| G | |
| H |
2. Term–definition match
The ten definitions below are shuffled. In the right-hand column write the matching term from this list: genotype, phenotype, enzyme, structural protein, transport protein, receptor protein, antibody, amino acid sequence, gene-environment interaction, phenotypic plasticity. 10 marks
| # | Definition (shuffled) | Matching term |
|---|---|---|
| 2.1 | The observable characteristics of an organism. | |
| 2.2 | A protein that speeds up a chemical reaction in living systems. | |
| 2.3 | The genetic makeup or allele combination of an organism. | |
| 2.4 | A protein involved in immune defence by recognising specific foreign molecules. | |
| 2.5 | The order of amino acids in a polypeptide, which folds into a protein's functional shape. | |
| 2.6 | A protein involved in moving substances across membranes or through the body. | |
| 2.7 | A protein that provides support and strength to tissues (e.g. collagen in connective tissue). | |
| 2.8 | A protein that binds signalling molecules and helps cells respond. | |
| 2.9 | The way a phenotype emerges from a combination of genes and environmental influence. | |
| 2.10 | The ability of one genotype to produce different phenotypes in different environments. |
3. True or false — with correction
For each statement, circle T or F. If the statement is false, write the corrected version. 8 marks (1 for T/F, 1 for the correction where needed)
3.1 Genes directly become observable traits with no intermediate molecule involved. T / F
3.2 A change in amino acid sequence can change a protein's shape, which can alter its function. T / F
3.3 If the environment changes a person's phenotype, then their genotype must have changed too. T / F
3.4 Two people with the same genotype for height can still reach different adult heights depending on nutrition during growth. T / F
4. Function recall
Answer each in 1–2 sentences using precise terms from the lesson. 10 marks (2 each)
4.1 What is the function of an enzyme in a living cell?
4.2 What is the function of a transport protein?
4.3 What is the function of a receptor protein?
4.4 What is the function of a protein's amino acid sequence in determining its overall role?
4.5 What is the function of environment in shaping phenotype when genotype is held constant?
5. Build a concept map
Draw labelled arrows between the five terms below to show how they connect. Each arrow must carry a linking phrase (e.g. "encodes", "influences", "shapes"). Aim for at least 5 labelled arrows. 5 marks
Supplied terms: genotype · protein (structure & function) · biological effect · phenotype · environment.
Q1 — Labelled diagram
A: genotype (the allele combination). B: protein production (genes contain information for producing proteins; their amino acid sequence). C: protein (folded chain of amino acids whose shape is set by its sequence). D: shape / structure (function depends on the correct folded shape). E: biological effect (the activity of the protein in the cell or organism — catalysis, transport, signalling, support, defence). F: phenotype (observable characteristics). G: environment influences phenotypic expression (without normally changing the genotype). H: nutrition affecting adult height when genetic potential is similar (any equivalent lesson example accepted, e.g. health during growth).
Q2 — Term–definition matches
2.1 phenotype • 2.2 enzyme • 2.3 genotype • 2.4 antibody • 2.5 amino acid sequence • 2.6 transport protein • 2.7 structural protein • 2.8 receptor protein • 2.9 gene-environment interaction • 2.10 phenotypic plasticity.
Q3 — True / false with correction
3.1 False. Correction: genes do not directly become traits — they influence the amino acid sequence of proteins, and protein function then contributes to phenotype. The intermediate molecule is the protein.
3.2 True.
3.3 False. Correction: environment can influence how a phenotype is expressed without normally changing genotype during ordinary development; genotype and phenotype are not the same thing.
3.4 True.
Q4.1 — Function of an enzyme
Enzymes catalyse (speed up) specific chemical reactions inside cells, controlling metabolic pathways. Their function depends on the correct folded shape, which is set by their amino acid sequence.
Q4.2 — Function of a transport protein
Transport proteins move substances across membranes or through the body (e.g. carrying ions across a cell membrane, or oxygen in blood). They allow cells and organisms to obtain, exchange and distribute the molecules they need.
Q4.3 — Function of a receptor protein
Receptor proteins bind specific signalling molecules and help cells detect and respond to signals from their environment or from other cells. Their function depends on a shape that matches the signal molecule.
Q4.4 — Function of amino acid sequence
The amino acid sequence determines how the protein folds into its three-dimensional shape, and the shape determines what jobs the protein can do (catalyse, transport, signal, support, defend). A changed sequence can therefore change function.
Q4.5 — Function of environment in shaping phenotype
Environmental factors (e.g. nutrition, temperature, sunlight, exercise) influence how the genotype is expressed as a phenotype. Two organisms with the same genotype can therefore show different phenotypes if their environments differ — without their DNA sequence changing.
Q5 — Sample concept map
A correct map should include arrows such as:
- genotype — encodes → protein (structure & function)
- protein (structure & function) — produces → biological effect
- biological effect — contributes to → phenotype
- environment — influences expression of → phenotype
- environment — can modify → biological effect (e.g. nutrition changing how a growth pathway runs)
Any biologically valid linking phrases are accepted. Award full marks for at least 5 correctly labelled arrows that respect causal direction.