Question

part c: short answer (6 questions)

1. explain what homeostasis is and why it is important for living organisms.
2. describe one way bacteria cause disease in the human body.
3. explain how viruses differ from bacteria in the way they cause disease.
4. give an example of a hereditary factor that may lead to disease.
5. why are bacteria and viruses such a threat to human health? provide two reasons.

Explanation:

Question 15

Homeostasis is the ability of an organism to maintain a stable internal environment (e.g., stable temperature, pH, glucose levels) despite external changes. It is important because biochemical processes, enzyme function, and cell structure rely on specific conditions. Without homeostasis, cells would malfunction, and the organism could not survive (e.g., enzymes denature at extreme temperatures/pH, so homeostasis keeps these within optimal ranges for metabolism).

One way bacteria cause disease is by producing toxins. Bacterial toxins (e.g., exotoxins or endotoxins) disrupt normal cell function. For example, Clostridium botulinum produces botulinum toxin, which blocks nerve signals, causing muscle paralysis (botulism). Alternatively, bacteria can invade and damage tissues (e.g., Streptococcus pyogenes invades throat tissue, causing strep throat, or Salmonella invades intestinal cells, causing diarrhea).

Viruses differ from bacteria in disease causation because viruses are non - living outside a host and must infect host cells to replicate. They hijack host cell machinery to make more viruses, damaging or killing the cell (e.g., influenza virus infects respiratory cells, causing cell lysis and flu symptoms). Bacteria are living, can reproduce independently (e.g., by binary fission), and cause disease by producing toxins, invading tissues, or competing with host cells for nutrients. Also, antibiotics kill bacteria but not viruses (since viruses lack bacterial structures like cell walls).

Answer:

Homeostasis is the maintenance of a stable internal environment (e.g., temperature, pH, nutrient levels) in an organism. It is important because biological processes (like enzyme activity, cell function) require specific conditions; without it, cells malfunction, and the organism cannot survive (e.g., enzymes denature outside optimal pH/temperature, so homeostasis preserves these for metabolism).

Question 16