1 A biologist studies deoxyribonucleic acid (DNA). Which biologist studies this? flag bookmark A Botanist B Oncologist C Ecologist D Geneticist T4 Chapter 1.1 Fields and Careers in Biology DNA carries the genes that are passed from parents to offspring. The study of genes and heredity is genetics, so the biologist is a geneticist. An oncologist studies cancer and an ecologist studies the relationship between organisms and their environment.
2 Diagram 1 shows the movement of substances through a plasma membrane. What are substances X and Y? | | X | Y | |---|---|---| | A | Sodium ion | Potassium ion | | B | Amino acid | Water | | C | Water | Sodium ion | | D | Glucose | Water | flag bookmark A Sodium ion – Potassium ion B Amino acid – Water C Water – Sodium ion D Glucose – Water T4 Chapter 3.3 Movement of Substances Across a Plasma Membrane in Living Organisms X passes straight through the phospholipid bilayer, so it is a very small molecule such as water. Y passes through a channel protein, which is used by ions such as sodium ions. Ions, glucose and amino acids cannot cross the phospholipid bilayer directly.
3 Pak Ali sprayed excessive fertiliser on his green bean plants, hoping that the plants would produce more fruits. A few days later, he found that the plants had wilted. What caused the green bean plants to wilt? flag bookmark A Water from the plant roots diffused into the soil by osmosis B The fertiliser diffused into the roots C The roots used too much energy to transport the fertiliser into the cells T4 Chapter 3.4 Movement of Substances Across a Plasma Membrane and Its Application in Daily Life Too much fertiliser makes the soil solution hypertonic to the root cell sap. Water moves out of the root cells into the soil by osmosis, the cells become plasmolysed and the plant wilts.
4 Diagram 2 shows the structure of a protein molecule. What is P? flag bookmark A Glucose B Fatty acid C Amino acid T4 Chapter 4.3 Protein A protein is a polypeptide chain made of many amino acids joined by peptide bonds. Each bead in the chain, such as P, is one amino acid. Glucose is the monomer of carbohydrates and fatty acids are part of lipids.
5 Diagram 3 shows the action of an enzyme on a substrate. Which of the following correctly represents P, Q and R? | | P | Q | R | |---|---|---|---| | A | Lactase | Glucose | Fructose | | B | Sucrase | Sucrose | Galactose | | C | Maltase | Glucose | Fructose | | D | Lactase | Glucose | Galactose | flag bookmark A Lactase – Glucose – Fructose B Sucrase – Sucrose – Galactose C Maltase – Glucose – Fructose D Lactase – Glucose – Galactose T4 Chapter 5.2 Enzyme Enzyme P breaks one substrate into two different products, Q and R. Lactase hydrolyses lactose into glucose and galactose. Sucrase gives glucose and fructose, and maltase gives two glucose molecules, so only D is a correct set.
6 Diagram 4 shows a phase in cell division. What are the possibilities that happen if structure P is not formed? I Incomplete crossing over II Homologous chromosomes do not separate III Can cause gene mutation IV One of the cells has a larger number of chromosomes flag bookmark A I and III B II and III C II and IV D III and IV T4 Chapter 6.4 Issues of Cell Division on Human Health P is a spindle fibre. Spindle fibres pull homologous chromosomes to opposite poles during anaphase I. Without them the homologous chromosomes do not separate (II), so one daughter cell gets more chromosomes than normal (IV). This is a change in chromosome number, not a gene mutation, and crossing over has already happened in prophase I.
7 Which of the following processes in plants require energy? I Mitosis II Water diffusion III Growth of pollen tube IV Absorption of mineral salts flag bookmark A I and II only B III and IV only C I, III and IV only D I, II, III and IV T4 Chapter 5.1 Metabolism Cell division (mitosis), the growth of the pollen tube and the active uptake of mineral salts by root hair cells all use energy from respiration. Diffusion of water (osmosis) is passive and does not need energy.
8 An athlete takes part in a 400 metre sprint event. Which equation represents his respiration process after he has run the first 200 metres? flag bookmark A Glucose → Lactic acid + energy B Glucose → Ethanol + carbon dioxide + energy C Glucose → Carbon dioxide + water + energy D Glucose + oxygen → Lactic acid + energy T4 Chapter 7.3 Fermentation During a sprint the muscles need energy faster than oxygen can be supplied, so the muscle cells also carry out lactic acid fermentation, which does not use oxygen: glucose → lactic acid + energy. Ethanol is produced by yeast, and D is wrong because fermentation does not use oxygen.
9 Diagram 5 shows the tracheal system of an insect. Air enters the muscle through X. What is X? flag bookmark A Bronchiole B Spiracle C Air sac D Tracheole T4 Chapter 8.1 Types of Respiratory System X is the opening on the body surface at the start of the tracheal system. This is a spiracle, through which air enters the tracheae and then the tracheoles that reach the muscle cells. Insects do not have bronchioles.
10 Complete burning of 0.4 g of peanuts increased the temperature of 20 ml of water from 30 °C to 70 °C. What is the energy value of the peanuts? (The specific heat capacity of water is 4.2 J g⁻¹ °C⁻¹) flag bookmark A 1.4 kJ B 3.4 kJ C 8.4 kJ D 76.2 kJ T4 Chapter 9.6 Balanced Diet Heat absorbed by the water = mass × specific heat capacity × temperature rise = 20 g × 4.2 J g⁻¹ °C⁻¹ × 40 °C = 3360 J. Energy value = 3360 J ÷ 0.4 g = 8400 J g⁻¹ = 8.4 kJ per gram of peanut.