Which of the following antibodies can cross the placenta?
- A. IgA
- B. IgD
- C. IgG
- D. IgM
Correct Answer: C
Rationale: The correct answer is IgG. IgG is the only antibody that can cross the placenta, providing passive immunity to the developing fetus. IgA, IgD, and IgM do not cross the placenta. IgA is mainly found in mucosal secretions, IgD is involved in the activation of B cells, and IgM is the first antibody produced in response to an infection, but it does not cross the placental barrier.
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What is the name of the long bone found in the upper arm?
- A. Femur
- B. Tibia
- C. Humerus
- D. Radius
Correct Answer: C
Rationale: The correct answer is the humerus. The humerus is the long bone located in the upper arm, between the shoulder and elbow. Option A, Femur, is incorrect as it is the long bone found in the thigh. Option B, Tibia, is incorrect as it is a long bone found in the lower leg. Option D, Radius, is incorrect as it is a bone located in the forearm, not the upper arm.
Which of the following is an example of an organ?
- A. Skin
- B. Neuron
- C. Brainstem
- D. DNA
Correct Answer: A
Rationale: The correct answer is A, 'Skin.' The skin is the largest organ in the human body and consists of multiple tissue types working together to perform various functions such as protection, sensation, and temperature regulation. Choice B, 'Neuron,' is a specialized cell in the nervous system and not an organ. Choice C, 'Brainstem,' is a part of the central nervous system composed of nerve tissues but is not an organ on its own. Choice D, 'DNA,' is a molecule that carries genetic instructions, not an organ.
Which element is essential for the formation of hemoglobin?
- A. Calcium
- B. Iron
- C. Potassium
- D. Sodium
Correct Answer: B
Rationale: The correct answer is Iron. Iron is essential for the formation of hemoglobin, the protein in red blood cells that binds and transports oxygen throughout the body. Calcium (Choice A), Potassium (Choice C), and Sodium (Choice D) are not directly involved in the formation of hemoglobin and its oxygen-carrying function.
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 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.