Nursing Elites

1. What enzymes do lysosomes contain, leading to their nickname as the cell's 'suicide bags'?

• A. Hydrolytic enzymes
• B. Ligases (bonding enzymes)
• C. Transferases (molecule transfer)
• D. Oxidoreductases (redox reactions)

Correct answer: A

Rationale: Lysosomes are organelles filled with hydrolytic enzymes that break down proteins, nucleic acids, lipids, and carbohydrates. These enzymes aid in digesting cellular waste and foreign substances, hence the term 'suicide bags' due to their involvement in cell degradation and recycling. Ligases are enzymes that catalyze the joining of two large molecules by forming a new chemical bond, not present in lysosomes. Transferases are enzymes that catalyze the transfer of functional groups from one molecule to another, not found in lysosomes. Oxidoreductases are enzymes involved in oxidation-reduction reactions, which are not the primary function of lysosomes.

2. In nuclear physics, the term 'barn' is a unit commonly used to quantify:

• A. Energy
• B. Radioactivity
• C. Nuclear cross-section
• D. Half-life

Correct answer: C

Rationale: In nuclear physics, the term 'barn' is a unit used to quantify nuclear cross-section. Nuclear cross-section is a measure of the probability of a nuclear reaction occurring when an atomic nucleus interacts with a particle or another nucleus. The barn is a unit of area equal to 10^-28 square meters; it is commonly used to describe the cross-sectional area of atomic nuclei for nuclear reactions. Choice A, 'Energy,' is incorrect because a barn is not a unit for measuring energy; it is a unit of area. Choice B, 'Radioactivity,' is incorrect as radioactivity is typically measured in units like becquerels. Choice D, 'Half-life,' is also incorrect as half-life is a measure of the time it takes for half of a substance to decay, not related to the concept of a barn as a unit of nuclear cross-section.

3. What type of cells compose the epidermis?

• A. Osteoclasts
• B. Connective
• C. Dendritic
• D. Epithelial

Correct answer: D

Rationale: The correct answer is D: Epithelial. The epidermis is composed of epithelial cells, specifically called keratinocytes, which are responsible for producing keratin, a protein that provides the skin with strength and flexibility. Epithelial cells form the protective outer layer of the skin and play a crucial role in skin repair and regeneration. Choice A - Osteoclasts are cells involved in bone remodeling, not found in the epidermis. Choice B - Connective tissue cells are not the primary cells found in the epidermis. They are more commonly found in the dermis, providing structural support and elasticity to the skin. Choice C - Dendritic cells are part of the immune system and are present in the skin to help recognize pathogens and activate the immune response. However, they are not the main cell type that composes the epidermis.

4. Two mice are both heterozygous for two traits: white fur (Ww) and short fur (Ss). Their offspring are most likely to have which of the following genotypes for these traits?

• A. wwss
• B. WWSS
• C. WwSs
• D. WWSs

Correct answer: C

Rationale: When two mice that are heterozygous for white fur (Ww) and short fur (Ss) mate, they can produce offspring with different combinations of the two traits. The Punnett square for this cross shows that the most likely genotype for the offspring is WwSs. In this case, each offspring receives one allele for white fur (W) and one for short fur (S) from each parent, resulting in a heterozygous genotype for both traits. Choice A (wwss) is incorrect as it represents a homozygous recessive genotype for both traits. Choice B (WWSS) is also incorrect as it represents a homozygous dominant genotype for both traits. Choice D (WWSs) is incorrect as it represents a genotype where one trait is homozygous dominant (W) and the other is heterozygous (S), which is not the most likely outcome based on the given parental genotypes.

5. Which type of muscle is characterized by voluntary control and is responsible for body movement?

• A. Cardiac muscle
• B. Smooth muscle
• C. Skeletal muscle
• D. Connective tissue

Correct answer: C

Rationale: The correct answer is skeletal muscle. Skeletal muscle is characterized by voluntary control, meaning it is under conscious control. It is responsible for body movement, such as walking, running, and lifting objects. Cardiac muscle is involuntary and found in the heart, while smooth muscle is also involuntary and found in organs like the intestines. Connective tissue is not a type of muscle but rather a type of tissue that provides support and structure in the body.

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