Nokea
Which of the following does not describe a general trait of macromolecules?
- A. They can exist as single chains.
- B. They can be branched.
- C. They all contain carbon, hydrogen, and phosphorus.
- D. They are all used by the body.
Correct Answer: C
Rationale: The correct answer is C. While many macromolecules contain carbon, hydrogen, and phosphorus, not all of them do. For example, lipids, a type of macromolecule, may not contain phosphorus. Choice A and B describe structural features that macromolecules can exhibit, whether as single chains or branched forms. Choice D is incorrect as not all macromolecules are used by the body, such as synthetic polymers or certain non-digestible fibers.
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What is the function of the Vas Deferens?
- A. Produces fluid to increase sperm mobility
- B. Site where the egg matures
- C. Helps control urine flow
- D. Connects each testis to the urethra
Correct Answer: D
Rationale: The vas deferens is a duct that connects each testis to the urethra, allowing the transport of sperm.
Choice A is incorrect because the vas deferens does not produce fluid to increase sperm mobility.
Choice B is incorrect as the vas deferens is not a site for egg maturation.
Choice C is incorrect as the vas deferens does not help control urine flow, its primary role is in the transport of sperm.
Which organ stores and concentrates bile?
- A. Liver
- B. Gallbladder
- C. Pancreas
- D. Stomach
Correct Answer: B
Rationale: The correct answer is B: Gallbladder. The gallbladder is the organ that stores and concentrates bile produced by the liver. Bile is essential for the digestion of fats in the small intestine. The liver produces bile, which is then stored and concentrated in the gallbladder until it is released into the small intestine when needed. Choices A, C, and D are incorrect because the liver produces bile, the pancreas produces digestive enzymes, and the stomach is primarily involved in the digestion of food through acid secretion and mechanical processes, not in storing bile.
Which part of the brain controls breathing and heart rate?
- A. Cerebrum
- B. Medulla oblongata
- C. Thalamus
- D. Cerebellum
Correct Answer: B
Rationale: The medulla oblongata is the correct answer because it is responsible for controlling involuntary functions such as breathing and heart rate. The cerebrum (Choice A) is primarily associated with higher brain functions like thinking and voluntary movements, not with regulating basic bodily functions like breathing and heart rate. The thalamus (Choice C) serves as a relay station for sensory information but is not directly involved in controlling breathing and heart rate. The cerebellum (Choice D) plays a role in coordination and balance, not in regulating respiratory and cardiac functions.
Which part of the cell is responsible for storing genetic information?
- A. Ribosome
- B. Mitochondrion
- C. Nucleus
- D. Cytoplasm
Correct Answer: C
Rationale: The correct answer is C, Nucleus. The nucleus is responsible for storing genetic information in the form of DNA. The DNA within the nucleus controls the activities of the cell by directing the synthesis of proteins and regulating gene expression. Choices A, Ribosome, B, Mitochondrion, and D, Cytoplasm, do not store genetic information. Ribosomes are involved in protein synthesis, mitochondria produce energy for the cell, and cytoplasm is a gel-like substance that houses organelles and where many cellular activities occur.
What does the P-wave in an ECG correspond to?
- A. Atrial repolarization
- B. Depolarization of SA node
- C. Ventricular depolarization
- D. Ventricular repolarization
Correct Answer: B
Rationale: The P-wave in an ECG represents the depolarization of the SA node and the atria, not atrial repolarization. Choice C, ventricular depolarization, is incorrect because the P-wave does not correspond to ventricular activity. Choice D, ventricular repolarization, is also incorrect as the P-wave does not depict ventricular repolarization. The correct interpretation is that the P-wave signifies the initiation of the electrical impulse at the SA node and subsequent atrial depolarization, making option B the correct answer.