Nursing Elites

1. What is the difference between a homozygous recessive genotype and a homozygous dominant genotype?

• A. Both have the same phenotype, but different genotypes.
• B. Both have the same genotype, but different phenotypes.
• C. Homozygous recessive has two dominant alleles, while homozygous dominant has two recessive alleles.
• D. Homozygous recessive has two identical recessive alleles, while homozygous dominant has two identical dominant alleles.

Correct answer: D

Rationale: - Homozygous recessive genotype refers to an individual having two identical recessive alleles for a particular gene (e.g., rr for a trait where r represents the recessive allele). - Homozygous dominant genotype refers to an individual having two identical dominant alleles for a particular gene (e.g., RR for a trait where R represents the dominant allele). - The difference between the two genotypes lies in the specific alleles present in each case, with homozygous recessive having two recessive alleles and homozygous dominant having two dominant alleles. - This genetic difference results in different phenotypes being expressed, as the dominant allele typically masks the expression of the recessive allele in heterozygous individuals.

2. What is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division?

• A. Centromere
• B. Chromatid
• C. Chromosome
• D. Gene

Correct answer: C

Rationale: A chromosome is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division. It contains the genetic material and is essential for cell division and replication. The centromere is a specific region of a chromosome that plays a role in cell division. A chromatid is one half of a duplicated chromosome, and a gene is a unit of heredity responsible for specific traits. Therefore, the correct answer is 'Chromosome' as it represents the entire condensed DNA molecule during cell division.

3. Which of the following best describes a chemical change?

• A. Melting ice to form water
• B. Dissolving sugar in water
• C. Burning wood to produce ash
• D. Crushing a can to reduce its size

Correct answer: C

Rationale: A chemical change involves a chemical reaction where new substances are formed. Burning wood to produce ash is an example of a chemical change because the wood undergoes a chemical reaction to form a new substance (ash). In this process, the chemical composition of wood changes to produce ash, which is a new substance. On the other hand, melting ice to form water, dissolving sugar in water, and crushing a can to reduce its size are examples of physical changes. In these instances, the substances may change their physical state or appearance but do not undergo a chemical reaction to form new substances. Therefore, choice C is the correct answer as it represents a chemical change, while choices A, B, and D represent physical changes.

4. How do vaccines stimulate the immune system to develop memory without causing full-blown illness? What type of molecule in a vaccine typically triggers the immune response?

• A. Toxins produced by the pathogen
• B. Live, attenuated (weakened) forms of the pathogen
• C. Inactivated (dead) forms of the pathogen
• D. Antigens (specific molecules) from the pathogen

Correct answer: D

Rationale: Vaccines work by triggering the immune system to develop memory without causing illness. They typically contain antigens, which are specific molecules from the pathogen. These antigens stimulate the immune system to produce a targeted immune response without causing full-blown sickness. By presenting these antigens, vaccines help the immune system create memory cells that remember the pathogen. This memory allows the immune system to respond more effectively if it encounters the pathogen in the future. Choices A, B, and C are incorrect because vaccines do not typically contain toxins, live pathogens, or inactivated forms of the pathogen. Instead, vaccines primarily rely on specific molecules (antigens) to induce an immune response.

5. Which part of the brain is responsible for controlling voluntary muscle movements?

• A. Cerebrum
• B. Cerebellum
• C. Medulla oblongata
• D. Thalamus

Correct answer: A

Rationale: The correct answer is the Cerebrum. The cerebrum, the largest part of the brain, controls voluntary muscle movements, along with cognitive functions like thinking, perception, and decision-making. It is crucial for motor coordination and the regulation of voluntary movements. The Cerebellum (Choice B) is responsible for coordinating movement, balance, and posture, but not specifically for voluntary muscle movements. The Medulla oblongata (Choice C) is involved in controlling autonomic functions like breathing and heart rate, not voluntary muscle movements. The Thalamus (Choice D) acts as a relay station for sensory information but is not primarily responsible for controlling voluntary muscle movements.

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