Biology 2008 Jamb Examination

The cortex is the region between the epidermis and the vascular tissues (which include the pericycle and stele). It consists of parenchyma cells that store food and provide support for the stem.

Food passes from the ileum (last part of the small intestine) into the caecum, then to the large intestine (colon), and finally to the rectum for excretion. This sequence ensures absorption of nutrients before waste is eliminated.

Insectivorous plants grow in nutrient-poor soils, especially deficient in nitrogen. They trap and digest insects to obtain nitrogen, which is essential for the synthesis of amino acids and proteins.

Birds lack teeth, so the gizzard functions as a mechanical digestive organ. It grinds food with the help of ingested grit, performing the role that teeth would in mammals.

Pawpaw X in concentrated salt solution will lose water by osmosis and become flaccid, while pawpaw Y in distilled water will gain water and become turgid. Water moves from a region of high water potential to low water potential.

$$C_6H_{12}O_6 + O_2 → 6CO_2 + 6H_2O + \text{Energy}$$ 
Exhaled air contains more water vapour than inhaled air because it is humidified in the respiratory tract and lungs. It also contains more carbon dioxide, but the main distinguishing feature is higher moisture content.

The Bowman's capsule, part of the nephron responsible for ultrafiltration of blood, is located in the renal cortex. It surrounds the glomerulus and initiates the process of urine formation.

Turgid parenchyma cells exert pressure against their cell walls, providing structural support to non-woody parts of plants. This turgidity helps maintain rigidity in leaves and stems.

Ovulation occurs when the mature egg is released from the Graafian follicle in the ovary. It is then captured by the ovarian funnel and transported to the fallopian tube for potential fertilization.

Nerve impulse transmission involves electrical changes across the nerve membrane and movement of ions such as sodium and potassium. This process, known as an action potential, allows rapid signal conduction along neurons.