Which of the following statements is true about an allergic reaction?
- A. An allergic reaction, such as hives or wheezing, results from overactive body systems such as the integumentary and respiratory systems.
- B. An allergic reaction is a result of overactive B-cells in the body that release various immunoglobulins.
- C. An allergic reaction is caused by overactive mast cells in the body, which are stimulated by Immunoglobulin E.
- D. An allergic reaction involves substances like histamine, keratin, and collagen.
Correct Answer: C
Rationale: The correct answer is C. Mast cells are responsible for releasing histamine and other chemicals during an allergic response. Choice A is incorrect because hives and wheezing are symptoms of an allergic reaction, not the causes. Choice B is incorrect as B-cells are not directly involved in allergic reactions. Choice D is incorrect as keratin and collagen are not typically involved in allergic reactions, and histamine is released by mast cells.
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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.
Which of the following is an example of Mendelian inheritance?
- A. Incomplete Dominance
- B. Polygenic Alleles
- C. Combination Inheritance
- D. Recessive Inheritance
Correct Answer: D
Rationale: The correct answer is D, 'Recessive Inheritance.' Mendelian inheritance involves traits controlled by single genes with dominant and recessive alleles. Incomplete dominance (choice A) is a non-Mendelian inheritance pattern where the heterozygous phenotype is a blend of the two homozygous phenotypes. Polygenic alleles (choice B) involve multiple genes contributing to a single trait, not following Mendelian principles. Combination inheritance (choice C) is not a recognized term in genetics and does not describe Mendelian inheritance patterns.
What is the function of the lymphatic system?
- A. To transport oxygen
- B. To filter waste from the blood
- C. To produce red blood cells
- D. To regulate body temperature
Correct Answer: B
Rationale: The correct answer is B: 'To filter waste from the blood.' The lymphatic system is responsible for draining excess fluid from tissues, absorbing fats from the digestive system, and filtering out harmful substances and waste products from the blood. It also plays a crucial role in the body's immune defense by transporting white blood cells and antibodies to fight off infections. Choices A, C, and D are incorrect because transporting oxygen, producing red blood cells, and regulating body temperature are functions performed by other systems in the body, such as the respiratory system, bone marrow, and thermoregulatory mechanisms, respectively.
Which of the following hormones is responsible for regulating blood sugar levels?
- A. Insulin
- B. Adrenaline
- C. Cortisol
- D. Melatonin
Correct Answer: A
Rationale: Insulin is the hormone responsible for regulating blood sugar levels by facilitating the uptake of glucose into cells. Insulin helps lower blood sugar levels by promoting the storage of glucose in the liver, muscle, and fat cells. Adrenaline, cortisol, and melatonin do not directly regulate blood sugar levels. Adrenaline is involved in the fight-or-flight response, cortisol is a stress hormone that affects metabolism, immune response, and anti-inflammatory actions, while melatonin regulates sleep-wake cycles.
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.