Nokea
What is the primary function of the circulatory system?
- A. To regulate body temperature
- B. To transport oxygen and nutrients
- C. To fight infection
- D. To break down waste
Correct Answer: B
Rationale: The correct answer is B: To transport oxygen and nutrients. The primary function of the circulatory system is to deliver oxygen and essential nutrients to cells throughout the body and remove waste products like carbon dioxide. Choice A is incorrect as regulating body temperature is primarily the function of the body's thermoregulatory system. Choice C is incorrect as fighting infection is mainly the role of the immune system. Choice D is incorrect as breaking down waste is primarily handled by the digestive system.
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What term refers to the mechanical act of breathing?
- A. Diffusion
- B. Perfusion
- C. Respiration
- D. Ventilation
Correct Answer: D
Rationale: Ventilation is the correct answer as it specifically refers to the mechanical process of breathing air in and out of the lungs. Diffusion (choice A) is the movement of molecules from an area of high concentration to low concentration, not related to the mechanical act of breathing. Perfusion (choice B) is the process of blood flow through the tissues and organs, not directly related to breathing mechanically. Respiration (choice C) involves the exchange of oxygen and carbon dioxide at the cellular level, different from the mechanical act of breathing.
Which of the following enzymes unwinds the double-stranded DNA during replication?
- A. Helicase
- B. Ligase
- C. Nuclease
- D. Polymerase
Correct Answer: A
Rationale: Helicase is the enzyme responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This process creates the replication fork where DNA polymerase can then synthesize new DNA strands. Ligase functions to join Okazaki fragments on the lagging strand, not unwind DNA. Nuclease is involved in DNA repair by removing damaged DNA segments. Polymerase is responsible for synthesizing new DNA strands based on the existing template strands, not for unwinding the DNA.
Which of the following structures in the cell is responsible for producing ATP?
- A. Ribosome
- B. Nucleus
- C. Mitochondria
- D. Endoplasmic reticulum
Correct Answer: C
Rationale: The correct answer is C, Mitochondria. Mitochondria are known as the powerhouse of the cell and are responsible for producing ATP, the primary energy currency of the cell through cellular respiration. Ribosomes (Choice A) are involved in protein synthesis, the nucleus (Choice B) stores genetic material and controls cell activities, and the endoplasmic reticulum (Choice D) plays a role in protein synthesis, lipid metabolism, and detoxification, but none of these structures are directly responsible for producing ATP.
Which of the following structures is responsible for producing insulin?
- A. Liver
- B. Pancreas
- C. Gallbladder
- D. Spleen
Correct Answer: B
Rationale: The correct answer is B: Pancreas. The pancreas is the organ responsible for producing insulin. Insulin is a hormone that helps regulate blood sugar levels by allowing cells to take in glucose from the bloodstream. The liver (choice A) plays a role in regulating blood sugar levels through glycogen storage and release but does not produce insulin. The gallbladder (choice C) stores bile produced by the liver to aid in digestion and has no direct involvement in insulin production. The spleen (choice D) is involved in immune function and blood storage but not in the production of insulin.
Which of the following lobes of the brain is primarily responsible for vision?
- A. Frontal
- B. Occipital
- C. Parietal
- D. Temporal
Correct Answer: B
Rationale: The occipital lobe is primarily responsible for processing visual information. It contains the primary visual cortex, which plays a key role in interpreting visual stimuli. The frontal lobe is more associated with functions such as decision-making and problem-solving, making choice A incorrect. The parietal lobe is involved in processing sensory information but not specifically vision, making choice C incorrect. The temporal lobe is responsible for functions like memory and auditory processing, so choice D is also incorrect.