Nursing Elites

1. Which of the following is NOT an example of a homeostatic mechanism?

• A. Shivering when the body temperature falls.
• B. Increasing heart rate when blood pressure is low.
• C. Weight gain when consuming excess calories.
• D. Secreting insulin to decrease blood sugar concentration.

Correct answer: C

Rationale: Weight gain when consuming excess calories is not an example of a homeostatic mechanism. Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. The other options listed (A, B, and D) involve physiological responses aimed at restoring balance or stability within the body (e.g., regulating body temperature, blood pressure, and blood sugar levels). Shivering, increasing heart rate, and secreting insulin are mechanisms to counteract specific imbalances and maintain internal equilibrium. In contrast, weight gain due to excess calorie intake does not represent a specific regulatory mechanism but rather an outcome of energy imbalance. The body stores excess energy as fat rather than actively regulating a physiological parameter to restore balance.

2. Cartilage, found in joints and the ear, is a type of:

• A. Epithelial tissue
• B. Connective tissue
• C. Muscle tissue
• D. Nervous tissue

Correct answer: B

Rationale: Cartilage is a type of connective tissue that provides support and flexibility to various parts of the body, such as joints and the ear. It is composed of cells called chondrocytes embedded in a matrix of collagen and proteoglycans. Epithelial tissue covers body surfaces, muscle tissue is involved in movement, and nervous tissue transmits signals. The correct answer is connective tissue because cartilage serves a supportive function in the body.

3. What property of a wave determines its speed in a given medium?

• A. Amplitude
• B. Wavelength
• C. Frequency
• D. Medium's properties

Correct answer: D

Rationale: The speed of a wave in a given medium is determined by the properties of that medium, such as its density and elasticity. While amplitude, wavelength, and frequency are important characteristics of a wave, they do not directly impact its speed in a specific medium. Amplitude refers to the maximum displacement of particles in a wave, wavelength is the distance between two successive points in a wave that are in phase, and frequency is the number of complete oscillations a wave makes in a given time. However, these properties do not dictate the speed of a wave in a particular medium. Therefore, the correct answer is the medium's properties.

4. What type of bond connects sugar and phosphate in DNA?

• A. Hydrogen
• B. Ionic
• C. Covalent
• D. Overt

Correct answer: C

Rationale: The correct answer is Covalent (C). In DNA, a covalent bond connects sugar and phosphate molecules. This bond involves the sharing of electron pairs between the atoms, providing stability to the DNA structure. Hydrogen bonds are important in DNA structure but are not the primary bond connecting sugar and phosphate. Ionic bonds involve the transfer of electrons, and 'overt' is not a term related to the bond connecting sugar and phosphate in DNA.

5. What is the significance of the nuclear envelope breaking down during mitosis?

• A. It allows the chromosomes to condense and become visible.
• B. It allows the spindle apparatus to form and attach to the chromosomes.
• C. It allows the sister chromatids to separate.
• D. It allows the nuclear material to be evenly distributed to the daughter cells.

Correct answer: B

Rationale: A) The breakdown of the nuclear envelope does not directly cause the chromosomes to condense and become visible. Chromosome condensation is a separate process that occurs before mitosis begins. B) The breakdown of the nuclear envelope is crucial for the formation of the spindle apparatus, a structure made of microtubules that helps separate the chromosomes during cell division. The spindle apparatus attaches to the chromosomes and helps move them to opposite poles of the cell. C) The separation of sister chromatids occurs during anaphase, which is facilitated by the spindle apparatus. The breakdown of the nuclear envelope is not directly involved in this process. D) The even distribution of nuclear material to daughter cells is achieved through the movement of chromosomes by the spindle apparatus, which is made possible by the breakdown of the nuclear envelope.

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