Nokea
According to the periodic table, which of the following elements is the least reactive?
- A. Fluorine
- B. Silicon
- C. Neon
- D. Gallium
Correct Answer: C
Rationale: Neon is the least reactive among the given elements because it belongs to the noble gases group in the periodic table. Noble gases have a full valence shell of electrons, making them highly stable and least likely to react with other elements. Fluorine is the most reactive non-metal due to its high electronegativity. Silicon is a metalloid with moderate reactivity, falling between metals and nonmetals. Gallium is a metal with higher reactivity compared to Neon, but it is not as reactive as Fluorine.
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Which of the following is the carbohydrate monomer?
- A. Disaccharide
- B. Lactose
- C. Monosaccharide
- D. Thymine
Correct Answer: C
Rationale: The correct answer is C: Monosaccharide. Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar unit. They are considered the carbohydrate monomers from which larger carbohydrates like disaccharides (composed of two sugar units) and polysaccharides (containing multiple sugar units) are built. Choices A and B, Disaccharide and Lactose, are not monomers but rather specific types of carbohydrates made up of multiple sugar units. Choice D, Thymine, is a nitrogenous base present in DNA and RNA, not a carbohydrate monomer.
Which plane divides the body into anterior (front) and posterior (back) halves?
- A. Sagittal/Median Plane
- B. Frontal/Coronal Plane
- C. Transverse/Cross-Section Plane
- D. Horizontal Plane
Correct Answer: B
Rationale: The correct answer is B - Frontal/Coronal Plane. This plane divides the body into anterior (front) and posterior (back) halves. The sagittal plane divides the body into left and right halves, the transverse plane separates the body into superior (upper) and inferior (lower) portions. The horizontal plane is not a standard anatomical term for body division and does not provide division into front and back halves.
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.
What is the function of the endocrine system?
- A. To protect the body from infection
- B. To release digestive enzymes
- C. To break down food
- D. To regulate the sleep-wake cycle
Correct Answer: B
Rationale: The correct answer is B. The endocrine system releases hormones that regulate various functions, including metabolism and growth. It is responsible for producing and releasing hormones that control processes such as metabolism, growth, and development. The digestive enzymes are released by the digestive system, not the endocrine system. Choices A, C, and D are incorrect because protecting the body from infection is primarily the role of the immune system, breaking down food is the function of the digestive system, and regulating the sleep-wake cycle is controlled by the circadian rhythm which is mainly influenced by the brain's hypothalamus and not the endocrine system.
Which of the following terms describes stem cells that have the ability to develop into any cell found in the human body?
- A. Totipotent stem cells
- B. Multipotent stem cells
- C. Pluripotent stem cells
- D. Hematopoietic stem cells
Correct Answer: A
Rationale: Totipotent stem cells have the unique ability to differentiate into any cell type in the human body and can generate a complete organism. They are considered the most versatile type of stem cells, capable of developing into all cell types, including extraembryonic tissues. Choice A, Totipotent stem cells, is the correct answer as it specifically describes stem cells with the broadest differentiation potential. Choice B, Multipotent stem cells, refers to stem cells that can differentiate into a limited range of cell types. Choice C, Pluripotent stem cells, can give rise to almost all cell types, but not the complete organism like totipotent stem cells. Choice D, Hematopoietic stem cells, are a type of multipotent stem cells that give rise to various blood cell types, but do not have the same broad differentiation potential as totipotent stem cells.