Questions: 1. What is the benefit of molecules forming the cell membrane being able to move. - Allows for cell membrane to have two layers - Allows membrane to be permeable - Allows membrane to be impermeable 2. A marathon runner experiences an increase in body temperature during a race. Which physiological mechanism is activated to cool down the body and maintain temperature homeostasis? - Shivering - Decreased sweating - Increased metabolic rate - Vasodilation of blood vessels 3. As product concentration Increases, the reaction rate of a chemical reaction will - Increase - Decrease - Remain constant

1. The answer is the second one: Allows membrane to be permeable.

Explanation:

• Allows for cell membrane to have two layers: This is incorrect. The ability of molecules to move within the cell membrane is not directly related to the membrane having two layers. The bilayer structure is due to the amphipathic nature of phospholipids.
• Allows membrane to be permeable: This is correct. The fluidity of the cell membrane, due to the movement of its molecules, allows for selective permeability, enabling the transport of substances in and out of the cell.
• Allows membrane to be impermeable: This is incorrect. If the membrane were impermeable, it would not allow substances to pass through, which is not a benefit of molecular movement.

2. The answer is the fourth one: Vasodilation of blood vessels.

Explanation:

• Shivering: This is incorrect. Shivering generates heat and is a response to cold, not heat.
• Decreased sweating: This is incorrect. Sweating is a cooling mechanism, so it would increase, not decrease, to cool the body.
• Increased metabolic rate: This is incorrect. An increased metabolic rate would generate more heat, not cool the body.
• Vasodilation of blood vessels: This is correct. Vasodilation increases blood flow to the skin, allowing more heat to be released from the body, thus cooling it down.

3. The answer is the second one: Decrease.

Explanation:

• Increase: This is incorrect. As product concentration increases, the reaction rate typically decreases due to the reaction reaching equilibrium or product inhibition.
• Decrease: This is correct. An increase in product concentration can lead to a decrease in reaction rate as the reaction approaches equilibrium or due to feedback inhibition.
• Remain constant: This is incorrect. Reaction rates are generally affected by changes in product concentration, especially in reversible reactions.

In summary, the answers are:

1. Allows membrane to be permeable.
2. Vasodilation of blood vessels.
3. Decrease.