Nokea
What is necessary for active transport through a membrane to take place?
- A. Glucose
- B. Oxygen
- C. Sodium
- D. ATP
Correct Answer: D
Rationale: Active transport through a membrane requires energy in the form of ATP (adenosine triphosphate). ATP provides the necessary energy for the transport proteins to move molecules against the concentration gradient, from an area of lower concentration to higher concentration. This process is essential for maintaining cellular functions and regulating the internal environment of a cell. Glucose, oxygen, and sodium are important molecules involved in various cellular processes, but they are not the primary energy source required for active transport across membranes. Therefore, the correct answer is ATP.
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In contrast with triglycerides, phospholipids are lacking one of which of the following components?
- A. Monosaccharide
- B. Glycerol
- C. Phosphates
- D. Fatty acid
Correct Answer: B
Rationale: Phospholipids are structurally similar to triglycerides but lack one of the fatty acid chains that triglycerides possess. Triglycerides consist of three fatty acid chains attached to a glycerol molecule, while phospholipids have two fatty acid chains and a phosphate group attached to a glycerol backbone. Therefore, phospholipids are lacking the third fatty acid chain found in triglycerides. Choice A (Monosaccharide) is incorrect because neither triglycerides nor phospholipids contain monosaccharides in their structure. Choice C (Phosphates) is incorrect because phospholipids actually contain phosphates, unlike triglycerides. Choice D (Fatty acid) is incorrect as both triglycerides and phospholipids contain fatty acids, but the number of fatty acid chains differs between the two.
Patient A, who weighs 68 kilograms, steps onto a scale 20 times. The scale consistently weighs Patient A as 75 kilograms. What is true of the measurement?
- A. It is valid, but not reliable.
- B. It is reliable, but not valid.
- C. It is both valid and reliable.
- D. It is neither reliable nor valid.
Correct Answer: B
Rationale: The correct answer is B: 'It is reliable, but not valid.' The measurement is reliable because it consistently provides the same result (75 kg). However, it is not valid because it does not accurately reflect the true weight of Patient A (68 kg). Choice A is incorrect because if the scale consistently shows the same weight (75 kg), it is reliable. Choice C is incorrect because although the scale is consistent, the measurement does not reflect the true weight, making it not valid. Choice D is incorrect as the measurement is reliable but lacks validity.
If both parents have polydactylism, what percentage of their offspring is predicted to manifest the anomaly?
- A. 25%
- B. 50%
- C. 75%
- D. 100%
Correct Answer: B
Rationale: When both parents have polydactylism, they each possess at least one dominant allele for polydactylism. Through a Punnett square analysis, it can be determined that 50% of their offspring will inherit the dominant allele from both parents. This results in a 100% chance of manifesting the anomaly (2 out of 4 possibilities). Therefore, 50% of the offspring are predicted to manifest the anomaly. Choices A, C, and D are incorrect as they do not align with the principles of Mendelian genetics and Punnett square analysis.
What is the function of decomposition in the carbon cycle?
- A. To produce light energy
- B. To convert carbon to fuel
- C. To release carbon dioxide
- D. To store food for consumers
Correct Answer: C
Rationale: The correct answer is C: 'To release carbon dioxide.' Decomposition in the carbon cycle involves breaking down dead organic matter into simpler substances. During this process, carbon is released in the form of carbon dioxide back into the atmosphere. This release of carbon dioxide is essential for recycling carbon and making it available for use by living organisms. Choices A, B, and D are incorrect because decomposition does not produce light energy, convert carbon to fuel, or store food for consumers; its primary role is to recycle carbon through the release of carbon dioxide.
If bacteria are placed in a strong solution of salt water, they will shrink as water moves out of the bacteria. What is this process called?
- A. Dehydration synthesis
- B. Hydrolysis
- C. Osmosis
- D. Isotonic transport
Correct Answer: C
Rationale: Osmosis is the process by which water molecules move across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. In this case, when bacteria are placed in a strong solution of salt water, the high concentration of solutes outside the bacteria causes water to move out of the bacteria, leading to shrinkage. This process is known as osmosis.
Dehydration synthesis (Choice A) is a process where molecules combine by removing water. Hydrolysis (Choice B) is the breakdown of molecules by the addition of water. Isotonic transport (Choice D) does not accurately describe the specific movement of water in or out of bacterial cells in a hypertonic solution.