Nursing Elites

1. Which of the following properties is NOT characteristic of a covalent bond?

• A. Sharing of electrons between atoms
• B. High melting and boiling points
• C. Low electrical conductivity in solid state
• D. Directional bonding

Correct answer: B

Rationale: Covalent bonds are formed by the sharing of electrons between atoms. This sharing results in the formation of molecules with directional bonding, where the atoms are held together in a specific orientation. Covalent compounds generally have low melting and boiling points compared to ionic compounds, as the intermolecular forces in covalent compounds are weaker. Additionally, covalent compounds do not conduct electricity in the solid state because the electrons are localized between the atoms and not free to move and carry charge.

2. A bottle of hand sanitizer contains 70% alcohol. If 5ml of sanitizer are used, how much pure alcohol is present?

• A. 1.4ml
• B. 2.1ml
• C. 2.8ml
• D. 3.5ml

Correct answer: D

Rationale: Multiply the total sanitizer volume (5ml) by the alcohol percentage (70%) to get 3.5ml of pure alcohol.

3. What is the term for the process of breaking a large molecule into smaller fragments by applying heat?

• A. Polymerization
• B. Hydrogenation
• C. Isomerization
• D. Pyrolysis

Correct answer: D

Rationale: Pyrolysis is the process of breaking down large molecules into smaller fragments by applying heat. The other choices involve different chemical processes.

4. What is the name of the monthly cycle in females that prepares the body for potential pregnancy?

• A. Ovulation cycle
• B. Menstrual cycle
• C. Implantation cycle
• D. Gestation cycle

Correct answer: B

Rationale: The correct answer is B: Menstrual cycle. The menstrual cycle is the monthly process in females where the lining of the uterus thickens in preparation for a potential pregnancy. If pregnancy does not occur, the lining sheds, resulting in menstruation. Ovulation is a key event within the menstrual cycle where an egg is released from the ovary, typically around the midpoint of the cycle. Implantation refers to the attachment of a fertilized egg to the uterus, which occurs after ovulation and fertilization. Gestation cycle refers to the period of pregnancy from conception to birth. Therefore, the menstrual cycle best describes the monthly process that prepares the body for potential pregnancy.

5. What is the process of converting DNA into a protein called?

• A. Transcription
• B. Translation
• C. Replication
• D. Mutation

Correct answer: A

Rationale: Transcription is the process of converting DNA into a molecule called messenger RNA (mRNA). This mRNA molecule carries the genetic information from DNA to the ribosomes, where it is used to make proteins.

6. Melanin, the pigment responsible for skin color, is produced by

• A. Keratinocytes (These cells produce keratin)
• B. Melanocytes
• C. Sebocytes (These cells produce sebum)
• D. Langerhans cells (These cells are part of the immune system)

Correct answer: B

Rationale: The correct answer is B: Melanocytes. Melanin, the pigment responsible for skin color, is produced by melanocytes, which are specialized cells located in the skin's epidermis. Melanocytes transfer melanin to keratinocytes, the predominant cell type in the epidermis, where it provides protection against UV radiation. Sebocytes produce sebum, an oily substance that helps moisturize the skin and hair. Langerhans cells are a type of immune cell that play a role in the skin's immune response. Therefore, the correct answer is B as melanocytes are specifically responsible for producing melanin.

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