Question 1: Sex determination is the biological process that decides whether an individual will develop as male or female. It is primarily controlled by specific chromosomes inherited from the parents. In humans, males typically have XY chromosomes, while females have XX chromosomes.

Answer: Sex determination involves the inheritance of sex chromosomes, where XY results in a male and XX results in a female.

Question 1: Define 'sex chromosome' and explain its role in determining sex in humans.

Answer: A sex chromosome is a chromosome that determines the sex of an individual; in humans, the X and Y chromosomes play this role, with the presence of Y typically leading to male development.

Question 2: Describe the difference between XX and XY chromosome combinations regarding sex determination.

Answer: XX results in a female, while XY results in a male.

Question 1: If a couple has a 25% chance of having a male child based on their genetic makeup, what is the probability (in percentage) of having a female child? Show your calculation.

Answer: 75%

Question 2: Using the formula P(female) = 1 - P(male), calculate the probability of a female offspring if the chance of a male is 40%.

Answer: 60%

Question 1: Design a simple experiment to determine the sex chromosome composition of a cell sample. Mention the variables involved and safety precautions to consider.

Answer: The experiment involves extracting cells, staining chromosomes, and observing under a microscope to identify XX or XY patterns. Variables include type of stain, temperature, and microscope settings. Safety precautions include wearing gloves, handling chemicals carefully, and proper disposal of biological waste.

Question 1: In a population, 48% of the individuals are males and 52% are females. Discuss whether this distribution aligns with typical human sex ratios and explain possible reasons for deviations.

Answer: The typical human sex ratio at birth is approximately 51% males and 49% females. The observed data shows a slight deviation, which could be due to sampling error, environmental factors, or demographic variations.

Question 1: Explain how the presence of the Y chromosome influences male development in humans. (6 marks)

Answer: The Y chromosome contains the SRY gene, which triggers the development of testes in the embryo. The testes produce testosterone, leading to the development of male secondary sexual characteristics. Without the Y chromosome, the embryo develops as female.

Question 1: Discuss how sex determination techniques are used in the agriculture industry, such as in livestock breeding or crop production.

Answer: Techniques like genetic testing are used to identify and select for desired sex traits in livestock, improving productivity and management. In crops, sex determination can be manipulated to optimize yield or control plant reproduction.