1 Diagram 1 shows a cow. Which of the directions **A**, **B**, **C** or **D** shows dorsal? flag bookmark A A B B C C D D T4 Chapter 1.3 Communicating in Biology Dorsal means towards the back (upper side) of a four-legged animal, so it is direction A. C is ventral (towards the belly), D is anterior (head) and B is posterior (tail).
2 Diagram 2 shows an animal cell. What is organelle P? flag bookmark A Nucleus B Golgi apparatus C Smooth endoplasmic reticulum D Rough endoplasmic reticulum T4 Chapter 2.1 Cell structure and function P is a system of flattened membrane sacs next to the nucleus with ribosomes (dots) on its surface. This is the rough endoplasmic reticulum, which carries proteins made by the ribosomes.
3 Diagram 3 shows the condition of a plant cell after being immersed in a hypotonic solution. Which of the parts labelled **P**, **Q**, **R** and **S** shows that the cell is turgid? flag bookmark A P B Q C R D S T4 Chapter 3.3 Movement of Substances Across a Plasma Membrane in Living Organisms In a hypotonic solution water enters the cell by osmosis and collects in the vacuole. P is the large, swollen vacuole that pushes the cytoplasm against the cell wall, which shows the cell is turgid.
4 Mrs. K sows fertiliser around her vegetable plants excessively. What are the effects on Mrs. K's vegetable plants? I Water diffuses out from the root hair cells by osmosis II Root cells become deplasmolysed III The plants wilt IV The vacuole becomes bigger flag bookmark A I and II B I and III C II and IV D III and IV T4 Chapter 3.3 Movement of Substances Across a Plasma Membrane in Living Organisms Too much fertiliser makes the soil solution hypertonic to the root hair cells. Water moves out of the root cells by osmosis (I), the cells become plasmolysed and the plants wilt (III). Deplasmolysis and a bigger vacuole happen only when cells gain water.
5 Diagram 4 shows a structure of one lipid molecule. Which of the following is **not** a function of the molecule in Diagram 4? flag bookmark A Reserves energy for humans B As a liner to protect internal organs C Forms the major component of plasma membrane D As heat insulator T4 Chapter 4.4 Lipids The molecule is a triglyceride: one glycerol joined to three fatty acids. Triglycerides store energy, cushion internal organs and insulate heat. The main component of the plasma membrane is the phospholipid, not the triglyceride.
6 Diagram 5 shows an observation when a butter-stained cloth was washed with a detergent that contains lipase enzyme. Which of the following temperatures might give the washing effect as shown in Diagram 5? flag bookmark A 55 °C B 40 °C C 20 °C D 5 °C T4 Chapter 5.3 Application of Enzymes in Daily Life The stain was removed completely, so the lipase worked best. Enzymes in biological detergents work fastest near body temperature, about 37–40 °C. At 55 °C the enzyme starts to denature, and at 20 °C or 5 °C it works slowly.
7 In which of the following phases of the cell cycle does chromosome replication occur? flag bookmark A G₁ phase B G₂ phase C S phase D M phase T4 Chapter 6.2 Cell Cycle and Mitosis DNA (and so each chromosome) is copied during the S phase (synthesis phase) of interphase. G₁ and G₂ are growth phases, and the M phase is when the cell divides.
8 The following information states the characteristics of an individual with a genetic disorder. - Slanted eyes - Mental retardation - Protruding tongue Which of the meiosis phases causes the genetic disease? flag bookmark A Prophase I B Metaphase I C Anaphase II D Telophase II T4 Chapter 6.4 Issues of Cell Division on Human Health These are signs of Down syndrome, caused by an extra chromosome 21. It happens through non-disjunction, when sister chromatids or homologous chromosomes fail to separate during anaphase of meiosis. Of the options, only anaphase II is a stage when chromosomes separate.
9 Diagram 6 shows the word equation of a metabolic reaction. Glucose → Lactic acid + energy What is the energy value produced by the reaction shown in Diagram 6? flag bookmark A 2898 kJ B 210 kJ C 150 kJ T4 Chapter 7.3 Fermentation Glucose broken down into lactic acid is lactic acid fermentation. One molecule of glucose gives only about 150 kJ of energy, because most of the energy stays in the lactic acid. Aerobic respiration gives 2898 kJ and alcoholic fermentation gives 210 kJ.
10 Emphysema is one of the diseases related to the human respiratory system. What is the cause of emphysema? flag bookmark A The opening of bronchiole tube becomes smaller B Alveolus loses its elasticity C The bronchiole walls become swollen D Bronchiole tube is blocked T4 Chapter 8.4 Health Issues Related to the Human Respiratory System In emphysema, substances in cigarette smoke damage the alveolar walls. The alveoli lose their elasticity and break down, so the surface area for gaseous exchange falls. Narrow or swollen bronchioles describe asthma and bronchitis.