Which of the following nucleic acids carries the genetic information copied from DNA to the ribosomes?

Correct Answer: B

Rationale: The correct answer is B: mRNA. Messenger RNA (mRNA) is responsible for carrying the genetic information copied from DNA to the ribosomes for protein synthesis. mRNA serves as a temporary copy of the genetic instructions stored in DNA and acts as a messenger between the nucleus and ribosomes in the cytoplasm where protein synthesis occurs. While rRNA (ribosomal RNA) and tRNA (transfer RNA) play essential roles in the process of translation at the ribosomes, mRNA is the nucleic acid directly involved in carrying the genetic code for protein synthesis. Therefore, choices A, C, and D are incorrect as DNA is the original genetic material, rRNA is a component of the ribosomes, and tRNA carries amino acids during protein synthesis, respectively.

Correct Answer: A

Rationale: Totipotent stem cells possess the unique ability to differentiate into any cell type, including forming an entire organism. These cells have the highest potency level and can give rise to both embryonic and extraembryonic cell types, allowing them to develop into a complete organism. Multipotent stem cells (Choice B) can differentiate into a limited range of cell types within a specific tissue or organ. Pluripotent stem cells (Choice C) can differentiate into any cell type in the body except for those needed to support and develop a fetus. Hematopoietic stem cells (Choice D) are a type of multipotent stem cell that can differentiate into various blood cell types.

Correct Answer: A

Rationale: Cytokinesis is the correct term for the division of the cytoplasm during cell division. It is the final stage of cell division, following either mitosis or meiosis, where the cytoplasm of a parent cell is divided into two daughter cells. Mitosis is the process of nuclear division, while meiosis is a type of cell division that results in four daughter cells with half the number of chromosomes of the parent cell. Apoptosis, on the other hand, is programmed cell death and not the division of the cytoplasm.

Correct Answer: A

Rationale: The correct answer is A: B cells, a type of white blood cell, are responsible for producing antibodies in response to pathogens. Antibodies play a crucial role in identifying and neutralizing foreign substances like bacteria and viruses in the body, aiding in the immune response and protecting against infections. This function is essential for maintaining a healthy immune system. White blood cells, including B cells, are produced in the bone marrow before entering the bloodstream. Platelets, not white blood cells, are a specialized class of blood cells that function to clot blood and stop bleeding. While white blood cells provide immunity, not all of them are active throughout life as some have specific lifespans and functions.

Correct Answer: D

Rationale: The corrected answer is D, 'All of the above.' The urinary system performs multiple essential functions to maintain the body's internal environment. Synthesizing calcitriol and secreting erythropoietin are crucial roles of the kidneys. Regulating the concentrations of sodium, potassium, chloride, calcium, and other ions helps in maintaining the electrolyte balance. Reabsorbing or secreting hydrogen ions and bicarbonate is vital for managing the body's acid-base balance. Furthermore, the urinary system is involved in detecting reductions in blood volume and pressure, aiding in the maintenance of blood pressure levels and fluid balance in the body.