Nokea
Which of the following types of stem cells can differentiate into any cell type, including forming an entire organism?
- A. Totipotent stem cells
- B. Multipotent stem cells
- C. Pluripotent stem cells
- D. Hematopoietic stem cells
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.
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What term describes the front of the body, for example, the kneecap?
- A. Posterior
- B. Anterior
- C. Superior
- D. Inferior
Correct Answer: B
Rationale: The correct answer is 'B: Anterior.' In anatomy, 'anterior' refers to the front of the body, like the kneecap. On the other hand, 'posterior' describes the back of the body. Choices 'C: Superior' and 'D: Inferior' relate to structures being above or below a reference point, respectively, and are not used to describe the front or back of the body. Therefore, 'Anterior' is the most appropriate term given the context provided in the question.
What is the pathway of deoxygenated blood in our body?
- A. From the lungs to the left ventricle
- B. From the body to the right atrium, then to the right ventricle, and finally to the lungs
- C. From the left atrium to the body
- D. From the aorta to the right atrium
Correct Answer: B
Rationale: The correct pathway of deoxygenated blood in our body involves blood returning from the body, entering the right atrium, then passing to the right ventricle, and eventually reaching the lungs for oxygenation. This sequence ensures that deoxygenated blood is pumped to the lungs, where it receives oxygen and releases carbon dioxide before circulating back to the body. Choices A, C, and D are incorrect because they do not follow the actual path of deoxygenated blood in the circulatory system.
What are the components of the male internal genitalia and their functions?
- A. Prostate gland: produces hormones
- B. Testes: produce sperm and testosterone
- C. Epididymis: stores and matures sperm
- D. Urethra: conducts urine and semen out of the body
Correct Answer: B
Rationale: The testes play a crucial role in male reproduction by producing sperm and testosterone. Sperm production is essential for fertility, while testosterone is responsible for the development of secondary sexual characteristics. The epididymis functions to store and mature sperm, allowing them to become motile. The prostate gland, not listed among the choices, secretes fluid that nourishes and protects sperm. The urethra serves the purpose of conducting both urine and semen out of the body, enabling the excretion of waste and reproductive fluids.
What is a monohybrid cross, and what is the ratio of dominant to recessive gene manifestation?
- A. A cross involving two traits, 9:3:3:1
- B. A cross involving one trait, 3:1
- C. A cross involving two traits, 1:2:1
- D. A cross involving one trait, 1:1
Correct Answer: B
Rationale: A monohybrid cross is a genetic cross involving one trait. The ratio of dominant to recessive gene manifestation in the offspring is typically 3:1 when both parents are heterozygous. This ratio is the genotypic ratio, not just the phenotype ratio, where the dominant allele is present in 3 out of 4 offspring, and the recessive allele is present in 1 out of 4 offspring. Choice A is incorrect because it describes a dihybrid cross ratio. Choice C is incorrect as it represents the genotypic ratio for a monohybrid cross involving incomplete dominance. Choice D is incorrect as it does not reflect the typical ratio for a monohybrid cross.
Which hormone is produced by the thyroid gland?
- A. Insulin
- B. Thyroxine
- C. Adrenaline
- D. Cortisol
Correct Answer: B
Rationale: The correct answer is B: Thyroxine. The thyroid gland produces thyroxine, a hormone essential for regulating metabolism. Insulin is produced by the pancreas to regulate blood sugar levels. Adrenaline is produced by the adrenal glands to prepare the body for the 'fight or flight' response. Cortisol is produced by the adrenal cortex in response to stress, not by the thyroid gland.