What is the key difference between spermatogenesis and oogenesis in terms of gamete production?

A. Spermatogenesis produces one viable sperm, while oogenesis produces four viable ova.

B. Spermatogenesis produces four viable sperm, while oogenesis produces one viable ovum.

C. Both processes produce an equal number of viable gametes.

D. Both processes result in gametes with the same amount of cytoplasm.

Which mechanism prevents polyspermy during fertilisation?

A. Release of digestive enzymes

B. Cortical reaction and zona reaction

C. Mitotic division of the zygote

D. Formation of the blastocyst

Why is the implantation of the blastocyst in the endometrium crucial for the continuation of pregnancy?

A. It facilitates external fertilisation.

B. It allows for the exchange of materials between mother and fetus.

C. It ensures the secretion of HCG to maintain progesterone levels.

D. It triggers the onset of meiosis in the fetus.

How does the placenta facilitate the exchange of materials between the mother and fetus?

A. By secreting estrogen and progesterone

B. By allowing diffusion of nutrients, gases, and waste products

C. By preventing the mixing of maternal and fetal blood

D. Both B and C

Which hormone is primarily responsible for stimulating the ovary to secrete progesterone during early pregnancy?

A. Estrogen

B. Oxytocin

C. HCG (Human Chorionic Gonadotropin)

D. FSH (Follicle-Stimulating Hormone)

a) Discuss the processes of spermatogenesis and oogenesis, highlighting the roles of mitosis, cell growth, meiosis, and differentiation in each. [4]

b) Explain how these processes result in different numbers of gametes with different amounts of cytoplasm. [3]

a) Discuss the concepts of internal and external fertilisation in animals, providing examples of each. [3]

b) Explain the mechanisms that prevent polyspermy during fertilisation. [4]

a) Discuss the importance of the implantation of the blastocyst in the endometrium for the continuation of pregnancy. [4]

b) Explain the role of HCG in stimulating the ovary to secrete progesterone during early pregnancy. [3]

a) Describe the ultrastructure of the glomerulus and Bowman's capsule and explain their role in ultrafiltration. [4]

b) Discuss the role of the proximal convoluted tubule in the selective reabsorption of useful substances. [3]

c) Explain how the loop of Henle maintains hypertonic conditions in the medulla. [3]

a) Discuss the correlation between the length of the loop of Henle and the need for water conservation in animals. [3]

b) Explain how ADH plays a role in the reabsorption of water in the collecting duct. [3]

c) Discuss how the placenta facilitates the exchange of materials between the mother and foetus. [4]

How are estrogen and progesterone secreted by the placenta once it has formed?

A. Through the activation of the cortical reaction

B. By stimulating the release of HCG from the ovary

C. By taking over the role of the corpus luteum in hormone secretion

D. Through the differentiation of blastocyst cells

Which concept is associated with the location of fertilisation in animals?

A. Polyspermy

B. Internal and external fertilisation

C. Implantation of the blastocyst

D. Differentiation of gametes

How is birth mediated by positive feedback involving estrogen and oxytocin?

A. Estrogen decreases uterine contractions, while oxytocin triggers labour.

B. Estrogen and oxytocin both inhibit the release of HCG.

C. Estrogen enhances the effect of oxytocin, leading to increased uterine contractions.

D. Oxytocin inhibits the secretion of estrogen, resulting in labour.

What is the primary role of meiosis in oogenesis and spermatogenesis?

A. Cell growth and differentiation

B. Formation of the placenta

C. Production of gametes with half the chromosome number

D. Prevention of polyspermy

Which of the following is a difference resulting from spermatogenesis and oogenesis?

A. Spermatogenesis results in gametes with more cytoplasm.

B. Oogenesis results in the production of more viable gametes.

C. Spermatogenesis involves internal fertilisation, while oogenesis involves external fertilisation.

D. Oogenesis results in one viable ovum with more cytoplasm, while spermatogenesis results in four viable sperm.

a) Explain the role of estrogen and progesterone secreted by the placenta once it has formed. [3]

b) Discuss how birth is mediated by positive feedback involving estrogen and oxytocin. [4]

c) Discuss the difference in blood composition between the renal artery and vein. [3]

a) Discuss the difference between osmoregulators and osmoconformers, providing examples of each. [3]

b) Explain the role of the Malpighian tubule system in insects in osmoregulation and nitrogenous waste removal. [4]

c) Discuss the correlation between the type of nitrogenous waste in animals and their evolutionary history and habitat. [3]

a) Discuss spermatogenesis and oogenesis, highlighting the roles of mitosis, cell growth, meiosis, and differentiation in each process. [4]

b) Explain how the processes in spermatogenesis and oogenesis result in different numbers of gametes with different amounts of cytoplasm. [3]

c) Discuss the concepts of internal and external fertilisation in animals, providing examples for each. [3]

d) Explain the mechanisms that prevent polyspermy during fertilisation. [2]

a) Discuss the importance of the implantation of the blastocyst in the endometrium for the continuation of pregnancy. [3]

b) Explain the role of HCG in stimulating the ovary to secrete progesterone during early pregnancy. [3]

c) Discuss how the placenta facilitates the exchange of materials between the mother and foetus and how it acts as a barrier. [4]

d) Discuss how birth is mediated by positive feedback involving estrogen and oxytocin. [2]

a) Explain how estrogen and progesterone are secreted by the placenta once it has formed and their roles in pregnancy. [3]

b) Discuss the correlation between the length of the loop of Henle and the need for water conservation in different animals. [3]

c) Discuss the difference between osmoregulators and osmoconformers, and how they maintain osmotic balance. [3]

d) Discuss the correlation between the type of nitrogenous waste in animals and their evolutionary history and habitat. [3]