Sexual Reproduction, Development and Growth in Humans and Animals

Question 9:A woman having problems getting pregnant needed an injection of hormone X from a specialist. Hormone X has the same function as the luteinizing hormone (LH). After a certain period, the woman was pregnant.Explain how the hormone X injection can help the woman to get pregnant. Answer:• Since the role of hormone X is … Read more

Question 7:Figure 1 shows the hormonal regulation of a menstrual cycle.Figure 1(a) State the effect on ovum development if hormone X is not enough.(b) Explain the effects of hormone P and hormone Y imbalance.(c) Based on Figure 1, describe the relationship between changes in structure T with the level of hormone P and hormone Q.(i) … Read more

Question 5:State the changes that occur to a zygote from fertilisation up to birth. Answer:The zygote divides repeatedly by mitosis. This cellular division produces a ball of cells, but the cell size is retained at this stage. Further development produces a solid ball of cells called morula. Then the morula will form a blastocyst, a … Read more

Question 1:What causes the premenstrual syndrome in some women? Answer:Imbalance of the oestrogen and progesterone levels Question 2:State the differences between the formation of identical and fraternal twins. Answer:Identical twins are formed when a fertilised ovum divides to form two zygotes whereas fraternal twins are produced when two simultaneously released ova are fertilised by two … Read more

Question 1:Describe how to measure growth in animals. Answer:Animal growth can be measured by measuring changes in size, volume, dry mass or wet mass. Question 2:Explain the differences between complete and incomplete metamorphosis. Answer:In complete metamorphosis, organisms undergo four stages of growth that is, egg, larva, pupa and adult. In incomplete metamorphosis, organisms undergo several … Read more

Question 1:What are the causes of impotency? Answer:• Hormone imbalance• Sex organ deformed or infected• Health issues such as cardiovascular diseases or diabetes• Immune system

Question 1:State two differences between identical and fraternal twins. Answer:• The genetic constitution and physical characteristics of identical twins are similar whereas for fraternal twins, they are different.• The sex of identical twins is the same but may be different for fraternal twins. Question 2:State the characteristics of conjoined twins. Answer:The physical part of Siamese … Read more

Question 1:Explain the early developmental process of the embryo. Answer:The process of early embryonic development• The zygote divides many times by mitosis.• The zygote forms a solid ball of cells called morula.• Morula forms a hollow sphere known as blastocyst.• Blastocyst then develops into an embryo. Question 2:What is the main function of the HCG … Read more

Question 1:State the hormones involved in the menstrual cycle and their functions. Answer:FSH• Stimulates oestrogen secretion• Stimulates follicle development in the ovaryLH• Causes ovulation• Causes the formation of corpus luteumOestrogen• Recovers and repairs endometrial tissues and stimulates the thickening of endometrium• Stimulates follicle development up to maturity• Stimulates secretion of FSH and LH before ovulationProgesterone• … Read more

Question 1:What could possibly happen if gametogenesis does not take place? Answer:Gametogenesis produces haploid gametes, that is, gametes that contain half the number of chromosomes of the parent cells. When the male and female gamete fuse, the new individual will have the same number of chromosomes as the parent cell (diploid). If gametogenesis does not … Read more