Nursing Elites

1. How are sister chromatids distinguished from homologous chromosomes in meiosis I?

• A. Sister chromatids share the same centromere, while homologous chromosomes have different centromeres.
• B. Sister chromatids have identical DNA sequences, while homologous chromosomes have slightly different sequences due to crossing over.
• C. Sister chromatids repel each other, while homologous chromosomes attract each other during synapsis.
• D. Sister chromatids separate during anaphase I, while homologous chromosomes separate during anaphase II.

Correct answer: B

Rationale: In meiosis I, sister chromatids are exact copies of each other, containing identical DNA sequences. On the other hand, homologous chromosomes are pairs of chromosomes, with one inherited from each parent, and they can have different versions of genes due to genetic recombination during crossing over in prophase I. Choice A is incorrect because homologous chromosomes naturally have different centromeres. Choice C is incorrect as sister chromatids and homologous chromosomes do not exhibit repulsion or attraction during synapsis. Choice D is incorrect as sister chromatids separate during anaphase II, not anaphase I, while homologous chromosomes separate during anaphase I.

2. Enzymes are ________ molecules that serve as _______ for certain biological reactions.

• A. Enzymes are irrelevant molecules that serve as suppressors for certain biological reactions.
• B. Enzymes are acidic molecules that serve as catalysts for certain biological reactions.
• C. Enzymes are lipid molecules that serve as catalysts for certain biological reactions.
• D. Enzymes are protein molecules that serve as catalysts for certain biological reactions.

Correct answer: D

Rationale: Enzymes are protein molecules that serve as catalysts for certain biological reactions. Enzymes are biological molecules that speed up chemical reactions in living organisms by lowering the activation energy required for the reactions to occur. They are typically proteins that have specific shapes and active sites that allow them to interact with specific substrates and facilitate reactions without being consumed themselves. The other choices are incorrect because enzymes are not irrelevant, acidic, or lipid molecules; they are primarily proteins known for their catalytic properties.

3. What is the function of the stratified cuboidal epithelium lining the salivary glands?

• A. Protection
• B. Gas exchange
• C. Secretion
• D. Absorption

Correct answer: C

Rationale: The correct answer is C: Secretion. The stratified cuboidal epithelium lining the salivary glands is responsible for secretion. This type of epithelium, made of multiple layers of cube-shaped cells, is specialized for secretion and protection. In the salivary glands, these cells secrete saliva to aid in the digestion process. Choice A, Protection, is incorrect because while the epithelium does provide some level of protection, its primary function in the salivary glands is secretion. Choice B, Gas exchange, is incorrect as the salivary glands are not involved in gas exchange processes. Choice D, Absorption, is also incorrect as the main role of this epithelium in the salivary glands is not absorption but rather secretion of saliva.

4. How many tissue layers make up the uterus?

• A. One.
• B. Two.
• C. Three.
• D. Four.

Correct answer: C

Rationale: The correct answer is C, 'Three.' The uterus is composed of three tissue layers: the endometrium, myometrium, and perimetrium. The endometrium is the innermost layer that thickens during the menstrual cycle and sheds during menstruation or supports a developing embryo during pregnancy. The myometrium is the middle layer, consisting of muscle tissue that contracts during labor. The perimetrium is the outer layer that covers the uterus. These three layers work together to support the functions of the uterus, such as menstruation, pregnancy, and labor. Choices A, B, and D are incorrect because the uterus is not made up of just one or two layers but rather three distinct tissue layers.

5. What term describes the functional unit of a skeletal muscle responsible for muscle contraction?

• A. Myofibril
• B. Sarcomere
• C. Tendon
• D. Myoglobin

Correct answer: B

Rationale: The correct answer is B, 'Sarcomere.' The sarcomere is indeed the functional unit of a skeletal muscle responsible for muscle contraction. It is composed of actin and myosin filaments that interact to generate muscle contraction. Choice A, 'Myofibril,' is incorrect as myofibrils are composed of sarcomeres, not the functional units themselves. Choice C, 'Tendon,' is incorrect as tendons connect muscles to bones and do not directly participate in muscle contraction. Choice D, 'Myoglobin,' is incorrect as myoglobin is a protein that stores oxygen in muscle cells and is not directly involved in muscle contraction.

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