Nursing Elites

1. Which type of wave does not require a medium for propagation?

• A. Transverse wave
• B. Longitudinal wave
• C. Mechanical wave
• D. Electromagnetic wave

Correct answer: D

Rationale: The correct answer is D, Electromagnetic wave. Electromagnetic waves do not require a medium for propagation because they consist of oscillating electric and magnetic fields that can travel through a vacuum. In contrast, transverse and longitudinal waves are mechanical waves that require a medium (solid, liquid, or gas) for propagation. Therefore, options A, B, and C are incorrect as they are all types of mechanical waves that necessitate a medium for transmission.

2. 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.

3. Which level of protein structure is defined by the folds and coils of the protein's polypeptide backbone?

• A. Primary
• B. Secondary
• C. Tertiary
• D. Quaternary

Correct answer: B

Rationale: The correct answer is B: Secondary. The secondary structure of a protein is defined by the folding and coiling of the polypeptide backbone into structures like alpha helices and beta sheets. Secondary structure primarily involves interactions such as hydrogen bonding within the backbone. This level of protein structure is distinct from primary structure (A) which refers to the linear sequence of amino acids, tertiary structure (C) which involves the overall 3D arrangement of a single polypeptide chain, and quaternary structure (D) which pertains to the interaction between multiple polypeptide chains in a protein complex.

4. What functional group is present in esters?

• A. Hydroxyl
• B. Carbonyl
• C. Ester
• D. Amine

Correct answer: C

Rationale: The functional group present in esters is -COO-, which represents a carbonyl group bonded to an oxygen atom. This group is responsible for the characteristic fruity aroma of esters. Choice A, 'Hydroxyl,' refers to -OH, which is a characteristic group of alcohols, not esters. Choice B, 'Carbonyl,' is a broad term that includes various compounds with a C=O group, but specifically in esters, it is a carbonyl group bonded to an oxygen atom. Choice D, 'Amine,' refers to compounds containing a nitrogen atom bonded to hydrogen atoms or alkyl groups, which is not present in esters. Therefore, the correct answer is 'C: Ester.'

5. 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.

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