Nokea
Which term refers to a molecule of DNA and structural protein?
- A. Lysosome
- B. Centrosome
- C. Chromosome
- D. Genome
Correct Answer: C
Rationale: The correct answer is C: Chromosome. A chromosome is a structure composed of DNA and proteins that carries genetic information. It is the condensed form of DNA associated with structural proteins, not just a molecule of DNA or protein. Lysosomes are membrane-bound organelles containing digestive enzymes, not DNA and protein. Centrosomes are involved in cell division, not related to DNA and protein together. A genome refers to an organism's complete set of DNA, not specifically a molecule containing both DNA and structural protein.
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What is a primary function of red blood cells?
- A. To fight infection
- B. To carry oxygen
- C. To produce antibodies
- D. To transport waste
Correct Answer: B
Rationale: The main function of red blood cells is to carry oxygen from the lungs to all the body's tissues and organs, where it is needed for cellular functions and metabolism. This process is essential for sustaining life and providing energy to cells. Choice A is incorrect because fighting infection is primarily done by white blood cells. Choice C is incorrect because antibody production is mainly carried out by specialized white blood cells. Choice D is incorrect as the primary role of red blood cells is not to transport waste, but rather to transport oxygen and some carbon dioxide.
Which of the following is the largest organ in the human body?
- A. Liver
- B. Brain
- C. Heart
- D. Skin
Correct Answer: D
Rationale: The skin is the largest organ in the human body. It covers the entire body, serving as a protective barrier against pathogens, UV radiation, and physical damage. Additionally, the skin plays a crucial role in regulating body temperature and synthesizing vitamin D when exposed to sunlight. Choices A, B, and C are incorrect. The liver is the largest internal organ, the brain is the control center of the body, and the heart is a vital organ responsible for pumping blood throughout the body. However, none of these organs are the largest in terms of surface area or overall size.
What is the role of the diaphragm in the respiratory system?
- A. To regulate blood pressure
- B. To contract and expand the lungs
- C. To produce red blood cells
- D. To absorb oxygen
Correct Answer: B
Rationale: The correct answer is B: To contract and expand the lungs. The diaphragm plays a crucial role in the respiratory system by contracting and expanding the lungs. When it contracts, it flattens, increasing the volume of the thoracic cavity and causing air to be drawn into the lungs. Conversely, when it relaxes, it moves back up, decreasing the thoracic cavity volume and pushing air out of the lungs. This process is essential for breathing and the exchange of oxygen and carbon dioxide in the body. Choices A, C, and D are incorrect. The diaphragm is not involved in regulating blood pressure, producing red blood cells, or absorbing oxygen. Its primary function is to aid in respiration by facilitating breathing through its contraction and relaxation movements.
Which structure in the eye is responsible for detecting light?
- A. Cornea
- B. Retina
- C. Lens
- D. Iris
Correct Answer: B
Rationale: The retina is the correct answer as it is the light-sensitive structure in the eye that detects light and converts it into signals for the brain to process visual information. The cornea is the transparent outer covering of the eye that helps to focus incoming light onto the lens. The lens further focuses the light onto the retina, which is where the actual light detection and signal conversion occur. The iris, on the other hand, controls the amount of light entering the eye by adjusting the size of the pupil but is not directly responsible for detecting light.
What type of tissue is found in the outermost layer of skin?
- A. Muscle tissue
- B. Connective tissue
- C. Epithelial tissue
- D. Nervous tissue
Correct Answer: C
Rationale: The correct answer is C: Epithelial tissue. Epithelial tissue forms the outermost layer of the skin, providing protection against external factors. It serves as a barrier and helps in preventing water loss and entry of pathogens into the body. Choice A, Muscle tissue, is incorrect as muscle tissue is responsible for movement, not skin structure. Choice B, Connective tissue, is incorrect as it provides support and structure to the body but is not the main component of the outermost layer of the skin. Choice D, Nervous tissue, is incorrect as nervous tissue is responsible for transmitting signals within the body, not for the outermost layer of the skin.