Nursing Elites

1. What impact would the removal of a keystone species have in an ecosystem?

• A. Lead to a decrease in competition among other species
• B. Cause a slight increase in primary productivity
• C. Have a minimal impact on the overall ecosystem structure
• D. Disrupt the food web and cause cascading effects on other populations

Correct answer: D

Rationale: Keystone species play a crucial role in maintaining the balance and structure of an ecosystem due to their significant influence. If a keystone species is removed, it disrupts the delicate food web dynamics and can trigger cascading effects throughout the ecosystem. The disruption in predator-prey relationships can lead to population declines and even extinctions of other species. Options A, B, and C are incorrect because the removal of a keystone species would not decrease competition among other species, cause a slight increase in primary productivity, or have a minimal impact on the overall ecosystem structure. Instead, it would have a profound impact, disrupting the food web and causing cascading effects on other populations.

2. Which of the following statements is NOT true about DNA?

• A. DNA contains the nucleotides A, T, C, G and is read 5' to 3'.
• B. DNA contains genetic information and is tightly coiled with proteins to form chromosomes.
• C. DNA contains the nucleotides A, T, C, G and is read 3' to 5'.
• D. DNA is a double-stranded molecule connected by hydrogen bonds.

Correct answer: C

Rationale: The correct answer is C because DNA is typically read from the 5' end to the 3' end, not from 3' to 5'. Choices A, B, and D are all true statements about DNA. DNA contains the nucleotides A, T, C, G and is read in a 5' to 3' direction. DNA also contains genetic information and is tightly coiled with proteins to form chromosomes. Additionally, DNA is a double-stranded molecule connected by hydrogen bonds.

3. Which brain structure is responsible for processing visual information?

• A. Cerebrum
• B. Occipital lobe
• C. Frontal lobe
• D. Brainstem

Correct answer: B

Rationale: The corrected question and choices are accurate. The correct answer is the Occipital lobe. The occipital lobe, located at the back of the brain, is primarily responsible for processing visual information received from the eyes. It plays a crucial role in interpreting and making sense of visual stimuli, allowing us to perceive and understand the world around us. The other choices, cerebrum (A), frontal lobe (C), and brainstem (D), do not have the primary function of processing visual information. The cerebrum is involved in higher brain functions, the frontal lobe is responsible for decision-making and personality, and the brainstem controls basic life functions like breathing and heart rate.

4. What is the main function of the pancreas?

• A. To store food and break it down into smaller pieces
• B. To absorb nutrients into the bloodstream
• C. To produce enzymes that help digest food
• D. To regulate blood sugar levels

Correct answer: C

Rationale: The main function of the pancreas is to produce digestive enzymes that aid in breaking down carbohydrates, fats, and proteins in food. These enzymes are essential for the digestion and absorption of nutrients in the small intestine. While the pancreas also plays a role in regulating blood sugar levels by producing insulin and glucagon, its primary function is to produce enzymes for food digestion. Options A and B are incorrect as the pancreas is not involved in storing food or absorbing nutrients into the bloodstream.

5. Which type of reaction typically undergoes condensation reactions?

• A. Catabolism
• B. Anabolism
• C. Exothermic
• D. Endothermic

Correct answer: B

Rationale: The correct answer is 'B: Anabolism.' Anabolic reactions typically involve condensation reactions, where smaller molecules are joined together to form larger molecules by releasing water as a byproduct. This process is fundamental in the synthesis of complex molecules such as proteins and nucleic acids. Choice A, 'Catabolism,' involves decomposition reactions where larger molecules are broken down into smaller ones, which is the opposite of condensation reactions. Choices C and D, 'Exothermic' and 'Endothermic,' refer to the heat exchange during a reaction and are not directly related to the process of condensation reactions.

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