Nursing Elites

1. Antigenic variation, a common strategy used by some viruses, allows them to:

• A. Produce toxins
• B. Evade the immune system
• C. Survive outside a host
• D. Replicate rapidly

Correct answer: B

Rationale: Antigenic variation is a strategy used by some viruses to evade the host's immune response. By constantly changing their surface antigens, viruses can avoid recognition and destruction by the immune system. This allows the virus to persist in the host and continue replicating, leading to prolonged infection and potential transmission to other hosts. Antigenic variation does not directly involve the production of toxins, survival outside a host, or rapid replication, making options A, C, and D incorrect in this context.

2. Which transport mechanism uses vesicles to move materials out of the cell?

• A. Endocytosis
• B. Active transport
• C. Diffusion
• D. Exocytosis

Correct answer: D

Rationale: Exocytosis is the transport mechanism that uses vesicles to move materials out of the cell. Vesicles carry substances to the cell membrane, fuse with it, and release their contents outside the cell. This process is essential for secreting molecules such as hormones, enzymes, or neurotransmitters. Endocytosis, on the other hand, is the process of bringing materials into the cell by engulfing them in vesicles. Active transport involves the movement of molecules across a cell membrane against their concentration gradient, requiring energy. Diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration.

3. An object is thrown upwards and reaches a maximum height. Which of the following statements is TRUE about its velocity and acceleration at the peak?

• A. Velocity is zero and acceleration is maximum upwards.
• B. Velocity is maximum and acceleration is zero.
• C. Velocity is maximum and acceleration is maximum upwards.
• D. Velocity is zero and acceleration is maximum downwards.

Correct answer: A

Rationale: At the peak of the object's motion, its velocity is zero because it momentarily stops before changing direction and starts to fall back down. The acceleration at the peak is maximum upwards as gravity is acting against the object's motion, slowing it down until it stops momentarily. Choice A is correct because at the peak, the object's velocity is zero, and the acceleration is maximum upwards. Choice B is incorrect because the velocity is not maximum but zero at the peak. Choice C is incorrect as both velocity and acceleration are not maximum at the peak. Choice D is incorrect as the acceleration at the peak is upwards, opposing the object's motion, not downwards.

4. Which muscular tube carries urine from the kidneys to the bladder?

• A. Nephron
• B. Ureter
• C. Urethra
• D. Glomerulus

Correct answer: B

Rationale: The correct answer is B: Ureter. The ureter is the muscular tube that carries urine from the kidneys to the bladder. The nephron is the functional unit of the kidney responsible for filtering blood and producing urine. The urethra is the tube that carries urine from the bladder out of the body. The glomerulus is a network of capillaries in the nephron where filtration of blood occurs.

5. What is the basic unit of heredity?

• A. Chromosome
• B. Cell
• C. Gene
• D. Organ

Correct answer: C

Rationale: A gene is the basic unit of heredity that carries the instructions for making proteins, which determine an organism's traits. Genes are segments of DNA located on chromosomes within the cell. While chromosomes contain many genes, a gene itself is the fundamental unit of heredity responsible for passing on genetic information from one generation to the next. Cells are the basic structural and functional units of living organisms, but genes specifically carry genetic information. Organs are composed of tissues and serve specific functions within an organism, but they are not the basic unit of heredity.

Similar Questions