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What do isotopes of the same element have in common?
- A. Identical number of protons and neutrons.
- B. Identical chemical properties.
- C. Identical number of electrons.
- D. Identical mass number.
Correct Answer: D
Rationale: Isotopes of the same element have the same number of protons, which defines the element, but different numbers of neutrons. This difference in neutron count results in isotopes of the same element having different mass numbers. Chemical properties are determined by the arrangement of electrons in an atom, so isotopes of the same element may exhibit slightly different chemical behaviors due to different neutron numbers. The number of electrons can vary in isotopes, affecting their charge. However, the mass number, which is the sum of protons and neutrons, is the same for isotopes of the same element. Therefore, the correct answer is that isotopes of the same element share an identical mass number.
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Which hormone, produced by the pituitary gland, stimulates the production of milk in mammary glands during breastfeeding?
- A. Growth hormone (GH)
- B. Thyroid-stimulating hormone (TSH)
- C. Prolactin
- D. Follicle-stimulating hormone (FSH)
Correct Answer: C
Rationale: Prolactin is the hormone produced by the pituitary gland that stimulates the production of milk in mammary glands during breastfeeding. It plays a crucial role in lactation by promoting the development of mammary tissue and the production of milk. Growth hormone (GH), thyroid-stimulating hormone (TSH), and follicle-stimulating hormone (FSH) do not directly stimulate milk production in mammary glands. Therefore, choices A, B, and D are incorrect in the context of stimulating milk production during breastfeeding.
What is the general formula for an alkene?
- A. CnH2n+2
- B. CnH2n
- C. CnH2n-2
- D. CnH2n+1
Correct Answer: B
Rationale: The general formula for an alkene is \(C_nH_{2n}\), indicating the presence of a double bond between carbon atoms.
Muscle tissue is responsible for movement. Which type of muscle tissue is found in the heart?
- A. Skeletal muscle
- B. Smooth muscle
- C. Cardiac muscle
- D. All of the above
Correct Answer: C
Rationale: Cardiac muscle is the type of muscle tissue found in the heart. Unlike skeletal muscle and smooth muscle, cardiac muscle is striated and involuntary, meaning it contracts without conscious control. It forms the majority of the heart's structure and is essential for its rhythmic contraction to pump blood throughout the body. Skeletal muscle is attached to bones and responsible for voluntary movements, while smooth muscle is found in organs and blood vessels, controlling various involuntary functions like digestion and blood flow. Therefore, choices A (Skeletal muscle) and B (Smooth muscle) are incorrect as they are not the types of muscle tissue found in the heart.
What is the process by which muscle tissue wastes away due to disuse or lack of nutrients?
- A. Hypertrophy
- B. Atrophy
- C. Fibrosis
- D. Rigor mortis
Correct Answer: B
Rationale: Atrophy is the correct term for the process by which muscle tissue wastes away due to disuse or lack of nutrients. It is essential to differentiate atrophy from hypertrophy, which is the increase in muscle size due to exercise or strength training. Fibrosis involves the formation of excess fibrous connective tissue, which is distinct from muscle wasting. Rigor mortis, on the other hand, is the stiffening of muscles that occurs after death and is not related to muscle wasting during life.
Differentiate between gene therapy and genetic engineering in the context of human intervention.
- A. Gene therapy aims to modify existing genes within body cells, while genetic engineering manipulates genes in embryos to be passed on to offspring.
- B. Gene therapy focuses on treating genetic diseases, while genetic engineering enhances desirable traits or eliminates undesirable ones.
- C. Both involve directly altering the DNA sequence, but gene therapy targets somatic cells and genetic engineering modifies germline cells.
- D. There is no fundamental difference; both terms are synonymous.
Correct Answer: B
Rationale: A) Incorrect. Gene therapy does aim to modify existing genes within body cells, but genetic engineering does not necessarily manipulate genes in embryos to be passed on to offspring. Genetic engineering can involve modifying genes in any type of cell, not just embryos.
B) Correct. Gene therapy is a medical intervention that aims to treat genetic diseases by correcting or replacing faulty genes within an individual's body cells. On the other hand, genetic engineering involves modifying genes to enhance specific traits or eliminate undesirable ones, often in the context of agriculture or biotechnology.
C) Incorrect. While both gene therapy and genetic engineering involve altering DNA sequences, the distinction lies in the target cells. Gene therapy targets somatic cells (non-reproductive cells), while genetic engineering typically involves modifying germline cells (reproductive cells that can pass on genetic changes to offspring).
D) Incorrect. There is