1. Explain the concept of homeostasis in the human body. Provide examples and discuss the importance of

maintaining a stable internal environment.

Answer: Homeostasis refers to the body's ability to maintain a relatively constant internal environment

despite external changes. This process is crucial for optimal physiological functioning. For example, the

body regulates body temperature by balancing heat production and dissipation through sweating or

shivering. Homeostasis is important as it allows cells to function optimally, enzymes to maintain their

proper shape, and prevents harmful deviations in key physiological variables.

2. Describe the structure and function of the cell membrane. Discuss its importance in maintaining cellular

homeostasis.

Answer: The cell membrane is a selectively permeable boundary that separates the cell's internal

environment from the external environment. It consists of a lipid bilayer with embedded proteins and

carbohydrates. The membrane regulates the passage of molecules in and out of the cell, allowing for the

maintenance of cellular homeostasis by controlling the transport of nutrients, waste products, and

maintaining the cell's internal pH and osmotic balance.

3. How does the process of cellular respiration occur in the human body? Explain the role of mitochondria

in this process.

Answer: Cellular respiration is the process by which cells convert glucose and oxygen into ATP (adenosine

triphosphate), the main energy currency of the cell. This process occurs in the mitochondria, which are

organelles responsible for energy production. Mitochondria contain enzymes necessary for the different

stages of cellular respiration, including glycolysis, the citric acid cycle, and oxidative phosphorylation.

Through these metabolic pathways, energy is released from glucose and oxygen, generating ATP and waste

products such as carbon dioxide and water.

4. Discuss the role of the endocrine system in the regulation of body functions. Provide examples of

hormones and their target organs.

Answer: The endocrine system is responsible for regulating various body functions through the secretion of

hormones. Hormones are chemical messengers that travel through the bloodstream to target organs, where

they produce specific effects. For example, insulin, secreted by the pancreas, regulates blood glucose levels

by facilitating glucose uptake into cells. Thyroid hormones, produced by the thyroid gland, control

metabolism and growth. Adrenaline, released by the adrenal glands, prepares the body for a "fight-or-flight"

response during stressful situations.