Nursing Elites

1. How does urine flow through the urethra?

• A. Continuously
• B. Only when the bladder is completely full
• C. Under voluntary control of sphincter muscles
• D. A combination of B and C

Correct answer: C

Rationale: Urine flows through the urethra under voluntary control of sphincter muscles. These muscles can be consciously contracted or relaxed to control the flow of urine from the bladder to the outside of the body. Choice A is incorrect as urine flow is not continuous but rather regulated. Choice B is incorrect because urine flow is not restricted to only when the bladder is completely full. Choice D is incorrect as it inaccurately combines the two incorrect statements of choices B and C.

2. Which of the following is responsible for maintaining the body's circadian rhythm?

• A. Thyroid gland
• B. Pineal gland
• C. Pancreas
• D. Hypothalamus

Correct answer: B

Rationale: The pineal gland is responsible for maintaining the body's circadian rhythm by producing melatonin. Melatonin is a hormone that helps regulate the sleep-wake cycle and is essential in controlling the body's internal clock. The thyroid gland, although important for metabolism, is not directly involved in regulating circadian rhythms. The pancreas plays a role in blood sugar regulation through insulin production, not in controlling circadian rhythms. The hypothalamus is involved in regulating various bodily functions, but the pineal gland is specifically responsible for the circadian rhythm.

3. What is the primary function of the myelin sheath that surrounds some axons in the nervous system?

• A. To initiate nerve impulses
• B. To transmit sensory information
• C. To speed up the transmission of nerve impulses
• D. To connect neurons at synapses

Correct answer: C

Rationale: The primary function of the myelin sheath is to speed up the transmission of nerve impulses. The myelin sheath acts as an insulating layer around the axon, allowing for faster conduction of electrical impulses along the nerve fiber. This insulation prevents the electrical signal from dissipating or 'leaking' out, which helps in the rapid and efficient transmission of nerve impulses along the axon. Choice A is incorrect because the myelin sheath does not initiate nerve impulses; it helps in conducting them. Choice B is incorrect as the myelin sheath's main role is not in transmitting sensory information but rather in facilitating the transmission of nerve impulses. Choice D is incorrect because the myelin sheath's function is not to connect neurons at synapses; instead, it is primarily involved in enhancing the speed of nerve impulse transmission.

4. What macromolecules are proteins that speed up chemical reactions and act as biological catalysts?

• A. Lipids
• B. Enzymes
• C. Carbohydrates
• D. Nucleic acids

Correct answer: B

Rationale: Enzymes are proteins that act as biological catalysts, speeding up chemical reactions without being consumed in the process. Lipids, carbohydrates, and nucleic acids do not serve as proteins that function as catalysts; they have different biological roles. Lipids are primarily used for energy storage, structural components, and signaling molecules. Carbohydrates are mainly for energy storage and providing structural support. Nucleic acids are involved in genetic information storage and transfer. Therefore, the correct answer is B: Enzymes.

5. What is the length of DNA that can code for a particular protein?

• A. Chromosome
• B. Nucleotide
• C. Gene
• D. Ribosome

Correct answer: C

Rationale: The correct answer is C: Gene. A gene is a specific segment of DNA that contains the information necessary to produce a particular protein. Genes are responsible for coding proteins, and each gene carries the instructions for a specific protein. Chromosomes consist of many genes and are not a specific length that codes for a protein. Nucleotides are the building blocks of DNA and are not a length that codes for a protein. Ribosomes are cellular organelles involved in protein synthesis and do not directly code for proteins.

Similar Questions