Nokea
What is the primary function of ribosomes in a cell?
- A. Protein synthesis
- B. DNA replication
- C. Cell division
- D. Lipid synthesis
Correct Answer: A
Rationale: The correct answer is A: Protein synthesis. Ribosomes are the cellular organelles responsible for protein synthesis. They read the messenger RNA (mRNA) and translate the genetic information into specific proteins. This process is essential for building and maintaining the structures and functions of the cell. Choice B, DNA replication, is incorrect because ribosomes are not involved in replicating DNA; that process occurs in the nucleus. Choice C, cell division, is incorrect as ribosomes are not directly involved in cell division but rather in protein synthesis. Choice D, lipid synthesis, is also incorrect as ribosomes are not responsible for synthesizing lipids, which primarily occurs in the endoplasmic reticulum and other organelles.
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Which of the following conditions is characterized by a high percentage of CO2 and a very low percentage of O2 in the blood?
- A. Asphyxia
- B. Emphysema
- C. Eupnea
- D. Hypoxia
Correct Answer: A
Rationale: Asphyxia is the correct answer as it refers to a condition with high CO2 and low O2 levels in the blood. Asphyxia can result in oxygen deprivation and excess carbon dioxide in the bloodstream, posing a life-threatening situation if not treated promptly. Emphysema is a chronic lung disease characterized by the damage to the air sacs in the lungs, leading to breathing difficulties. Eupnea denotes normal breathing without any abnormalities. Hypoxia, on the other hand, involves low oxygen levels reaching the body's tissues, which can result from various causes such as reduced oxygen in the air or respiratory issues.
Which organ is responsible for detoxifying harmful substances in the body?
- A. Kidneys
- B. Liver
- C. Heart
- D. Pancreas
Correct Answer: B
Rationale: The correct answer is the Liver. The liver is the organ responsible for detoxifying harmful substances in the body. It accomplishes this by metabolizing drugs and filtering blood. The liver plays a crucial role in maintaining overall health by processing and eliminating toxins. Choices A, C, and D are incorrect. The kidneys primarily filter blood to remove waste and excess substances, the heart is responsible for pumping blood throughout the body, and the pancreas aids in digestion and regulating blood sugar levels, but none of these organs are primarily responsible for detoxification.
What is the function of the pleurae?
- A. To compartmentalize and lubricate the lungs
- B. To facilitate the flow of air
- C. To produce mucus
- D. To serve as the passageway for air
Correct Answer: A
Rationale: The pleurae play a crucial role in compartmentalizing and lubricating the lungs. The pleura is a double-layered membrane that surrounds the lungs and lines the chest cavity. This double-layered structure reduces friction between the lungs and the chest wall during breathing movements, allowing smooth expansion and contraction of the lungs. Options B, C, and D are incorrect. Option B, 'To facilitate the flow of air,' is incorrect because while the pleurae are involved in the respiratory process, their primary function is not to directly facilitate the flow of air. Option C, 'To produce mucus,' is incorrect as the production of mucus is not a primary function of the pleurae. Option D, 'To serve as the passageway for air,' is incorrect as the passageway for air refers to the air passages like the trachea and bronchi, not the pleurae. Therefore, option A is correct as it accurately describes the function of the pleurae.
Which type of blood cell is responsible for clotting?
- A. Red blood cells
- B. Platelets
- C. White blood cells
- D. Plasma
Correct Answer: B
Rationale: Platelets are responsible for blood clotting. They help prevent excessive bleeding by forming clots at the site of blood vessel injuries. Platelets release chemicals that initiate the clotting process, leading to the formation of a stable clot that stops bleeding. Red blood cells are primarily responsible for carrying oxygen throughout the body and do not play a direct role in clotting. White blood cells are part of the immune system, fighting off infections and foreign invaders. Plasma is the liquid component of blood that carries various substances such as nutrients, hormones, and waste products, but it is not directly involved in clotting.
Which organ system is primarily responsible for transporting nutrients throughout the body?
- A. Respiratory
- B. Digestive
- C. Circulatory
- D. Nervous
Correct Answer: C
Rationale: The circulatory system, also known as the cardiovascular system, is primarily responsible for transporting nutrients and oxygen throughout the body. The heart pumps blood through blood vessels, delivering essential nutrients to cells and tissues. This system consists of the heart, blood vessels, and blood, working together to ensure the proper distribution of nutrients and removal of waste products. Choice A, the respiratory system, is responsible for gas exchange (oxygen and carbon dioxide) and not primarily involved in nutrient transportation. Choice B, the digestive system, is responsible for breaking down food and absorbing nutrients but does not transport nutrients throughout the body. Choice D, the nervous system, controls and coordinates body functions through electrical signals and is not directly involved in nutrient transportation.