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1. (a) Organisms from the genus Chlorella are protoctists. State the additional information required to name Chlorella according to the binomial system. [1]
(b) Fig. 1.1 shows the structure of an organism from the genus Chlorella.
(i) Identify two cell structures in Fig. 1.1 that indicate that Chlorella is not a prokaryote. [2]
(ii) Identify two cell structures in Fig. 1.1 that are found in both fungi and protoctists. [2]
(iii) State the names of two other kingdoms, apart from fungus, prokaryote and protoctist. [1]
(c) Chlorella is sold as a nutritional supplement. Spirulina is another nutritional supplement. Table 1.1 shows some nutritional information for Chlorella and Spirulina supplements and the recommended daily intake for some nutrients. [Table_1]
(i) One tablet contains 5 g of Chlorella supplement. Using the information in Table 1.1, calculate the number of tablets of Chlorella supplement a person needs to take to provide the recommended daily intake of iron. [3]
(ii) Explain the advantages of taking Chlorella as a dietary supplement rather than Spirulina. Use the data in Table 1.1 to justify your answer. [4]
(iii) State the name of one food that is a principal dietary source of vitamin C. [1]
(d) Chlorella is also a good source of protein.
(i) State the importance of proteins in active transport. [2]
(ii) State the name of the smaller molecules that proteins are made from. [1]
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2. (a) Fig. 2.1 is a diagram of the gas exchange system in humans.
(i) State the names of the parts labelled X, Y and Z in Fig. 2.1. [3]
(ii) The wall of the trachea contains rings of tissue. State the name of this tissue and describe its function. [2]
(iii) State the names of two types of cells responsible for protecting the breathing system from particles. [2]
(b) A scientist estimated the pressure and volume in the thorax during one breath. Fig. 2.2 shows a graph of the results.
Describe and explain the changes in the thorax that occur during section A only in Fig. 2.2. [5]
(c) Complete the sentences to describe the effect of carbon dioxide concentration on breathing. During physical activity, the carbon dioxide concentration of the blood _____ . This is detected by the ______ . This results in an increased rate and greater _____ of breathing. [3]
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3. (a) Fig. 3.1 shows a kidney nephron and its associated blood vessels.
The compositions of fluids A, B and C were analysed. Table 3.1 shows the results for five components of the fluids. [Table_2]
(i) State the names of fluid A and fluid C in Fig. 3.1. [2]
(ii) Using the information in Fig. 3.1 and Table 3.1, describe and explain the differences in the compositions of fluids A, B and C. [5]
(b) Outline how blood glucose concentration is controlled. [6]
(c) A gene mutation may be involved in the development of type 1 diabetes. (i) Describe what is meant by a gene mutation. [2]
(ii) Outline the treatment of type 1 diabetes. [3]
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4. (a) Fig. 4.1 shows a diagram of two flowers from different plants of the same species.
(i) Describe what is meant by the term species. [2]
(ii) Complete the diagram in Fig. 4.1 to show self-pollination and cross-pollination by: drawing one arrow to show the pathway of pollen during self-pollination and labeling this arrow self-pollination, drawing one arrow to show the pathway of pollen during cross-pollination and labeling this arrow cross-pollination, labeling the names of the structures involved in pollination. [3]
(iii) State the function of the parts labelled X and Y in Fig. 4.1. [2]
(b) Explain why self-pollination that results in production of offspring is a form of sexual reproduction and not asexual reproduction. [3]
(c) State the type of environmental conditions that hydrophytes are adapted to live in. [1]
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5. Fig. 5.1 is a pedigree diagram showing the inheritance of blood group in one family.
(a) State the number of people in Fig. 5.1 with: XY chromosomes _____. only one \( I_A \) allele. ______. [2]
(b) Explain how Fig. 5.1 shows that blood group is an example of discontinuous variation. [2]
(c) State one example of discontinuous variation in plants. [1]
(d) Explain why the inheritance of blood group is an example of codominance. [2]
(e) A person with the genotype \( I_AI_o \) has a child with a person with the genotype \( I_BI_o \). Complete the genetic diagram to determine the probability of the offspring having the blood group AB. [4]
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6. (a) The flow chart in Fig. 6.1 shows one pathway of nitrogen as it travels through the nitrogen cycle. Complete the flow chart in Fig. 6.1. [5]
(b) State the names of two processes that occur in both the carbon and nitrogen cycles. [2]
(c) State the principal source of energy input to biological systems. [1]
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