Define the following branches of Biology: Taxonomy, Microbiology. Explain metabolic rate relative to body size and the conditions under which lactic acid is formed. Identify the organelle and its func

1.

a) The branch of Biology that involves the study of organisms for the sake of classifying them is Taxonomy.

b) The branch of Biology that involves the study of microscopic organisms is Microbiology.

2.

a) This question refers to the concept of metabolic rate and body size. Smaller animals generally have a higher metabolic rate per unit body mass compared to larger animals. This is because smaller animals have a larger surface area to volume ratio, leading to greater heat loss, and thus need to generate more heat per unit mass to maintain a constant body temperature. Therefore, a mouse requires significantly more energy per kilogram of body weight than a dog.

b) Lactic acid is formed in human muscles under anaerobic conditions. This occurs during intense physical activity when the oxygen supply to the muscles is insufficient to meet the energy demands. Glucose is then broken down incompletely through anaerobic respiration, producing lactic acid as a byproduct along with a small amount of ATP.

3.
The diagram shows a chloroplast.

a) The function of the organelle above (chloroplast) is to carry out photosynthesis, the process by which light energy is converted into chemical energy in the form of glucose.

b)

• (i) Oxygen gas is produced as a by-product in the thylakoids (specifically, during the light-dependent reactions).
• (ii) Carbon (IV) oxide (carbon dioxide) is used in the stroma (during the light-independent reactions, also known as the Calvin cycle).

4.
Homeostasis is the process by which living organisms maintain a stable internal environment despite changes in external conditions.

Three processes in humans involved in homeostasis are:

• Thermoregulation: Maintaining a constant body temperature.
• Osmoregulation: Regulating water and salt balance in the body.
• Blood glucose regulation: Controlling the level of glucose in the blood.