Nokea
What is the function of a totipotent cell?
- A. Fights infection
- B. Develops into any type of cell
- C. Aids in the maturation of sex cells
- D. Carries electrical impulses
Correct Answer: B
Rationale: Totipotent cells possess the remarkable ability to differentiate into any cell type in the body, encompassing both embryonic and extraembryonic cell varieties. This quality is crucial in the early stages of embryonic development, facilitating the generation of all cell lineages and tissues. Unlike pluripotent or multipotent cells, totipotent cells exhibit the most extensive differentiation potential, playing a vital role in the organism's development from a single fertilized egg cell.
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Which of the following cell types produce and release antibodies?
- A. Helper T cells
- B. Cytotoxic T cells
- C. Plasma B cells
- D. Natural Killer cells
Correct Answer: C
Rationale: Plasma B cells are specialized cells that are responsible for producing and releasing antibodies. These antibodies play a vital role in the immune response by recognizing and neutralizing harmful pathogens like bacteria and viruses. Helper T cells aid in activating B cells and other immune cells, cytotoxic T cells are involved in eliminating infected or abnormal cells, and natural killer cells are part of the innate immune system, targeting virus-infected and tumor cells.
Which of the following physiological responses is caused by the release of anti-diuretic hormone?
- A. Decrease in water reabsorption in the collecting duct
- B. Decrease in the concentration of calcium in the glomerulus
- C. Increase in the concentration of calcium in the glomerulus
- D. Increase in water reabsorption in the collecting duct
Correct Answer: D
Rationale: The correct answer is D: Increase in water reabsorption in the collecting duct. Anti-diuretic hormone (ADH), also known as vasopressin, acts on the kidneys to increase water reabsorption in the collecting ducts, leading to the concentration of urine and conservation of water in the body. This hormone helps regulate water balance by decreasing urine output and increasing blood volume and pressure when needed.
The triple point of a substance is the temperature and pressure at which of the substance exists as which of the following?
What is the triple point of a substance?
- A. Simultaneously in solid, liquid, and gas phases.
- B. As soil with gas and solid trapped in liquid.
- C. As a gel with solid and liquid trapped in gas.
- D. Simultaneously in solid, gel, and plasma phases.
Correct Answer: A
Rationale: The triple point of a substance refers to the specific temperature and pressure at which the substance can exist in equilibrium as solid, liquid, and gas phases simultaneously. This unique point represents the conditions under which all three phases coexist in equilibrium, allowing for phase transitions without a change in temperature or pressure. It is a crucial concept in thermodynamics and phase diagrams, illustrating the conditions where a substance can exhibit distinct phases simultaneously.
Which type of chemical reaction is exemplified by the following equation? 2HCl (aq) + Mg(OH)₂ (s) → 2H₂O (l) + MgCl₂ (aq)
- A. Neutralization
- B. Decomposition
- C. Combustion
- D. Synthesis
Correct Answer: A
Rationale: The given chemical equation represents a neutralization reaction. In this reaction, an acid (hydrochloric acid) reacts with a base (magnesium hydroxide) to form water and a salt (magnesium chloride). Neutralization reactions typically involve the combination of an acid and a base to produce a salt and water. Choices B, C, and D are incorrect as they do not accurately describe the reaction type demonstrated in the equation provided.
Which of the following substances is excreted by the sweat glands in response to the breakdown of proteins and the formation of ammonia?
- A. Lysozymes
- B. Water
- C. Urea
- D. Sebum
Correct Answer: C
Rationale: The correct answer is Urea. Sweat glands excrete urea in response to the breakdown of proteins and the formation of ammonia. Urea is a waste product formed in the liver by the breakdown of amino acids. It is then excreted by the kidneys in urine and by sweat glands through perspiration. Urea plays a vital role in the excretory process by helping eliminate nitrogenous wastes from the body and maintaining proper physiological balance.