1 The following information is about a field of study in Biology. > Study of the interactions between organisms and their environment. What is the field of study? flag bookmark A Botany B Genetics C Ecology D Physiology T4 Chapter 1.1 Fields and Careers in Biology Ecology is the study of how organisms interact with each other and with their environment. Botany is the study of plants, genetics is the study of inheritance, and physiology is the study of how body parts work.
2 Diagram 1 shows the structure of a plant cell. Which of the following is true about component X? flag bookmark A Surrounded by the tonoplast membrane B Consists of two layers of membrane C Made from cellulose fibre T4 Chapter 2.1 Cell structure and function X is the large central vacuole. It is surrounded by a single membrane called the tonoplast and contains cell sap. Organelles such as the chloroplast and mitochondrion have two membranes, and the cell wall is made of cellulose.
3 Diagram 2 shows the structure of the plasma membrane. Which of the following is the characteristic of P? flag bookmark A Absorbs water B Attracted to water C Repels water T4 Chapter 3.1 Structure of Plasma Membrane P is the phosphate head of a phospholipid molecule. The head is hydrophilic, meaning it is attracted to water, so the heads face the watery fluid on both sides of the membrane. The fatty acid tails are hydrophobic and repel water.
4 The following information is about the health of a child. - Loss of water - Diarrhoea What is the substance that can help her to recover? flag bookmark A Reverse osmosis water B Isotonic drinks C Oral rehydration salts D Distilled water T4 Chapter 3.4 Movement of Substances Across a Plasma Membrane and Its Application in Daily Life Diarrhoea makes the body lose a lot of water and mineral salts. Oral rehydration salts contain the right amounts of glucose and salts to replace what was lost, and the glucose helps the intestine absorb sodium and water. Plain water does not replace the lost salts.
5 Diagram 3 shows a nucleotide. What are the types of pentose sugar and nitrogenous bases for RNA? | | Pentose sugar | Nitrogenous base | |---|---|---| | A | Deoxyribose sugar | Adenine, guanine, thymine and cytosine | | B | Ribose sugar | Adenine, guanine, cytosine and uracil | | C | Deoxyribose sugar | Adenine, guanine, cytosine and uracil | | D | Ribose sugar | Adenine, guanine, thymine and cytosine | flag bookmark A Deoxyribose – A, G, T, C B Ribose – A, G, C, U C Deoxyribose – A, G, C, U D Ribose – A, G, T, C T4 Chapter 4.5 Nucleic Acids RNA nucleotides contain ribose sugar and the bases adenine, guanine, cytosine and uracil. DNA contains deoxyribose sugar and has thymine instead of uracil.
6 Diagram 4 shows the breaking down of a complex molecule by an enzyme. Which of the following can be deduced from Diagram 4? I Enzyme acts rapidly II The reaction of enzyme is specific III Enzyme is only required in small quantities IV The structure of enzyme remains unchanged at the end of the reaction flag bookmark A I and II B I and III C II and IV D III and IV T4 Chapter 5.2 Enzyme The substrate fits exactly into the active site of the enzyme, which shows that the enzyme is specific (II). After the products are released, the enzyme has the same shape as at the start, so it is unchanged at the end of the reaction (IV). The diagram does not show speed or the amount of enzyme needed.
7 Diagram 5 shows stages in mitosis. What happens during stage R? flag bookmark A The chromosomes are aligned in a single row at the equatorial plane B The centrioles move to the opposite poles and spindle fibres start to form C Spindle fibres shorten, contract and the sister chromatids separate and are pulled to the opposite poles D When the chromatids are at the opposite poles, they are now called daughter chromosomes T4 Chapter 6.2 Cell Cycle and Mitosis The diagram already shows prophase (chromosomes inside the nucleus, bottom left), metaphase (chromosomes lined up at the equator, top left) and telophase (two nuclei forming, bottom right). The missing stage R is anaphase, when the spindle fibres shorten and the sister chromatids separate and are pulled to opposite poles (C). Option A describes metaphase, which is already drawn. (Note: the answer scheme gives A; on checking, our AI thinks C is more accurate, so both A and C are accepted.)
8 The following equation shows a type of fermentation that occurs in human muscle cells. Glucose → K + Energy What are K and the total energy released? | | K | Energy (kJ) | |---|---|---| | A | Lactic acid | 150 | | B | Ethanol | 150 | | C | Lactic acid | 210 | | D | Ethanol | 210 | flag bookmark A Lactic acid – 150 kJ B Ethanol – 150 kJ C Lactic acid – 210 kJ D Ethanol – 210 kJ T4 Chapter 7.3 Fermentation Fermentation in human muscle cells is lactic acid fermentation, so K is lactic acid. Only about 150 kJ of energy is released from one mole of glucose, because most of the energy stays in the lactic acid. Yeast fermentation produces ethanol and releases about 210 kJ.
9 Diagram 7 shows two organisms, P and Q. Which of the following shows the correct respiratory structure for the organisms? | | P | Q | |---|---|---| | A | Tracheole | Skin | | B | Lungs | Skin | | C | Lungs | Tracheole | | D | Tracheole | Lungs | flag bookmark A Tracheole – Skin B Lungs – Skin C Lungs – Tracheole D Tracheole – Lungs T4 Chapter 8.1 Types of Respiratory System P is a beetle, an insect, which breathes through a tracheal system that ends in tracheoles. Q is a rabbit, a mammal, which breathes with lungs.
10 The following statement describes the modifications to the structure and function of the gastric glands. > The inner surface of the stomach wall is lined by epithelial cells that undergo structural and functional modifications forming chief cells, parietal cells and mucus cells. Which of the following statements are true about the epithelial cells in the digestion of protein in the stomach? I Chief cells secrete caseinogen II Chief cells secrete pepsinogen III Mucus cells secrete sulphuric acid IV Parietal cells secrete hydrochloric acid flag bookmark A I and II B I and III C II and IV D III and IV T4 Chapter 9.2 Digestion Chief cells secrete pepsinogen (and prorennin), which becomes pepsin in acid (II). Parietal cells secrete hydrochloric acid (IV). Caseinogen is a milk protein, not a secretion, and mucus cells secrete mucus, not acid.