What is an alteration in the normal gene sequence called?
- A. DNA mutation
- B. Gene migration
- C. Polygenic inheritance
- D. Incomplete dominance
Correct Answer: A
Rationale: A DNA mutation is the correct term used to describe an alteration in the normal gene sequence. It refers to changes in the DNA sequence that can result in different traits or characteristics. Gene migration involves the movement of genes between populations, polygenic inheritance refers to the inheritance of traits controlled by multiple genes, and incomplete dominance is a pattern of inheritance where neither allele is dominant.
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Which blood component is chiefly responsible for clotting?
- A. Platelets
- B. Red blood cells
- C. Antigens
- D. Plasma cells
Correct Answer: A
Rationale: The correct answer is A: Platelets. Platelets are small cell fragments in the blood that play a crucial role in clotting. When there is an injury, platelets adhere to the site and release chemicals that help form a clot to prevent excessive bleeding. Red blood cells transport oxygen, antigens are substances that trigger an immune response, and plasma cells are a type of white blood cell involved in producing antibodies, none of which are primarily responsible for clotting.
Which of the following best defines the term amphoteric?
- A. A substance that conducts electricity due to ionization when dissolved in a solvent
- B. A substance that can act as an acid or a base depending on the properties of the solute
- C. A substance that, according to the Br¸nsted-Lowry Acid-Base Theory, is a proton-donor
- D. A substance that donates its proton and forms its conjugate base in a neutralization reaction
Correct Answer: B
Rationale: An amphoteric substance can act as both an acid or a base depending on the environment. It can donate a proton (act as an acid) or accept a proton (act as a base), showing versatility in its behavior. Choice A is incorrect as it describes an electrolyte rather than an amphoteric substance. Choice C is incorrect as it defines an acid based on the Br¸nsted-Lowry Acid-Base Theory. Choice D is incorrect as it specifically refers to a substance donating a proton in a neutralization reaction, not capturing the dual behavior of an amphoteric substance.
Which of the following correctly lists the four properties that all types of muscle tissue share?
- A. Contractile, excitable, elastic, extensible
- B. Contractile, voluntary, elastic, extensible
- C. Contractile, excitable, voluntary, extensible
- D. Contractile, excitable, elastic, voluntary
Correct Answer: A
Rationale: The correct answer is A: 'Contractile, excitable, elastic, extensible.' All types of muscle tissue share these four properties. Muscle tissue can contract, respond to stimuli, stretch and return to its original shape (elastic), and extend or stretch (extensible). Choice B is incorrect because not all muscle tissues are voluntary (some are involuntary). Choice C is incorrect because not all muscle tissues are voluntary. Choice D is incorrect because not all muscle tissues are voluntary and lack the elastic property.
Which of the following structures acts like a funnel by delivering urine from the millions of collecting tubules to the ureters?
- A. The renal pelvis
- B. The renal cortex
- C. The renal medulla
- D. Bowman's capsule
Correct Answer: A
Rationale: The correct answer is A: The renal pelvis. The renal pelvis serves as a reservoir for urine collected from the kidney's numerous collecting tubules, funneling it into the ureters for transport to the bladder. The renal cortex is the outer region of the kidney involved in filtration, while the renal medulla is the inner region responsible for concentrating urine. Bowman's capsule is part of the nephron and is involved in the initial filtration of blood in the kidney, not in funneling urine to the ureters.
Which of the following lists of joint types is in the correct order for increasing amounts of permitted motion (least mobile to most mobile)?
- A. Hinge, condyloid, saddle
- B. Saddle, hinge, condyloid
- C. Saddle, condyloid, hinge
- D. Hinge, saddle, condyloid
Correct Answer: A
Rationale: The correct order of joint types, from least mobile to most mobile, is hinge, condyloid, saddle. A hinge joint allows movement in one plane (like a door hinge), a condyloid joint allows movement in two planes but not rotation (like the wrist), and a saddle joint allows movement in multiple directions (like the thumb). Choice A, 'Hinge, condyloid, saddle,' is the correct sequence as it accurately represents the order of increasing permitted motion in joints. Choices B, C, and D are incorrect because they do not follow the correct order of joint types from least mobile to most mobile as required by the question.