2020 - JAMB Biology Past Questions and Answers - page 1

Insulin is a hormone that lowers the level of glucose (a type of sugar) in the blood. It's made by the beta cells of the pancreas and released into the blood when the glucose level goes up, such as after eating. Insulin helps glucose enter the body's cells, where it can be used for energy or stored for future use. Via: https://kidshealth.org/en/parents/insulin.htm

Deamination, the process of removing an amino group from a molecule, primarily occurs in the liver. The liver is the main organ responsible for processing amino acids and converting them into other substances, including urea, which is then excreted by the kidneys.

The hyphae of *Rhizopus* are described as non-septate because they lack cross-walls (septa). Septa are the partitions that divide the hyphae into individual cells. Therefore, the absence of these cross-walls is the defining characteristic of non-septate hyphae.

The function of a ribosome in a cell is protein synthesis. Ribosomes are the sites where mRNA is translated into proteins.

External fertilization is the process where the fusion of gametes (sperm and egg) occurs outside the body of the female. This is common in aquatic environments where sperm can easily reach the eggs. * **Toads:** Toads are amphibians, and amphibians typically exhibit external fertilization in water. The female toad releases eggs, and the male toad releases sperm, fertilizing the eggs in the surrounding water. * **Lizards, birds, and cockroaches:** These animals are terrestrial and have internal fertilization.

The villi are small, finger-like projections that line the inner surface of the small intestine. Their primary function is to increase the surface area available for the absorption of digested nutrients into the bloodstream.

Butterflies play important roles as pollinators to most agricultural crops.

The male peacocks display their beautiful fanned trains as part of their courtship behaviour.

Biotic components, or biotic factors, can be described as any living component that affects another organism or shapes the ecosystem. This includes both animals that consume other organisms within their ecosystem, and the organism that is being consumed. Wikipedia

The relationship between epiphytes (plants that grow on other plants) and their host trees is an example of commensalism. * **Commensalism:** This is a relationship where one organism benefits, and the other is neither harmed nor helped. Epiphytes benefit by gaining access to sunlight, water, and nutrients without harming the host tree. * **Parasitism:** This is a relationship where one organism (the parasite) benefits at the expense of the other (the host). * **Saprophytism:** This is a type of nutrition where an organism obtains nutrients from dead or decaying organic matter. * **Holophytism:** This refers to a type of plant that obtains its food through photosynthesis.