What is the main function of the epiglottis, a small flap of cartilage located above the larynx?
- A. To warm and humidify inhaled air
- B. To control the passage of food and air
- C. To produce sound vibrations for speech
- D. To sense the presence of foreign objects
Correct Answer: B
Rationale: The main function of the epiglottis is to control the passage of food and air. It acts as a cover for the trachea during swallowing to prevent food from entering the airway. This mechanism ensures that food safely travels down the esophagus to the stomach, while air simultaneously enters the trachea and moves into the lungs for respiration. Choice A is incorrect as the warming and humidifying of inhaled air primarily occur in the nasal cavity. Choice C is incorrect because sound production for speech involves structures like the vocal cords rather than the epiglottis. Choice D is incorrect as sensing foreign objects is not a primary function of the epiglottis; instead, this role is typically associated with sensory receptors in the respiratory tract.
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Which of the following functional groups is present in carboxylic acids?
- A. Carbonyl
- B. Hydroxyl
- C. Carboxyl
- D. Aldehyde
Correct Answer: C
Rationale: Carboxylic acids contain the carboxyl functional group, which consists of a carbonyl group (C=O) and a hydroxyl group (-OH) attached to the same carbon atom. The carboxyl group is represented as -COOH in the molecular structure of carboxylic acids. Therefore, the correct functional group present in carboxylic acids is the carboxyl group, making option C the correct choice. Option A, 'Carbonyl,' is incorrect as it only refers to the C=O group without the -OH component present in carboxylic acids. Option B, 'Hydroxyl,' is incorrect as it only represents the -OH group without the carbonyl group. Option D, 'Aldehyde,' is incorrect as it refers to a different functional group with a carbonyl group attached to a hydrogen atom, not the carboxyl group found in carboxylic acids.
What scientific term encompasses a permanent alteration in the DNA sequence?
- A. Trait
- B. Mutation
- C. Allele
- D. Variation
Correct Answer: B
Rationale: A) Trait: A trait is a characteristic or feature of an organism that is determined by its genes.
B) Mutation: A mutation is a permanent alteration in the DNA sequence that can result from errors during DNA replication, exposure to mutagens, or other factors.
C) Allele: An allele is a variant form of a gene that can result in different traits or characteristics.
D) Variation: Variation refers to the differences in traits or characteristics among individuals of the same species, which can be influenced by genetic and environmental factors.
In this context, the term that specifically refers to a permanent alteration in the DNA sequence is "mutation."
Which property of a substance refers to its ability to be hammered or pressed into thin sheets without breaking?
- A. Malleability
- B. Ductility
- C. Viscosity
- D. Conductivity
Correct Answer: A
Rationale: Malleability is the correct answer as it is the property of a substance that allows it to be hammered or pressed into thin sheets without breaking. This property is crucial for materials like metals that need to be shaped without breaking. Ductility, on the other hand, refers to the ability of a substance to be drawn into thin wires, not hammered into sheets. Viscosity is a measure of a fluid's resistance to flow, indicating its thickness or thinness, and is unrelated to the ability to be hammered. Conductivity, on the other hand, refers to a substance's ability to conduct electricity or heat, which is not related to its ability to be hammered or pressed into thin sheets.
The Minimum Inhibitory Concentration (MIC) of an antibiotic refers to:
- A. The lowest concentration that kills bacteria
- B. The dose required for 50% bacterial inhibition
- C. The time it takes for an antibiotic to work
- D. The spectrum of bacteria the antibiotic targets
Correct Answer: B
Rationale: A) The lowest concentration that kills bacteria is known as the Minimum Bactericidal Concentration (MBC), not the Minimum Inhibitory Concentration (MIC). MIC is the lowest concentration of an antibiotic that inhibits visible growth of bacteria.
B) The MIC of an antibiotic is the concentration at which bacterial growth is inhibited by 50%. This concentration is used to determine the effectiveness of an antibiotic against a specific bacterium.
C) The time it takes for an antibiotic to work is not described by the MIC. MIC is a measure of concentration, not time.
D) The spectrum of bacteria the antibiotic targets is not defined by the MIC. The MIC value is specific to a particular antibiotic and bacterium, regardless of the spectrum of activity of the antibiotic.
What is the scientific term for scar tissue?
- A. Epithelial tissue
- B. Fibrous connective tissue
- C. Cartilage
- D. Adipose tissue
Correct Answer: B
Rationale: The correct scientific term for scar tissue is fibrous connective tissue. Scar tissue is primarily composed of fibrous connective tissue, which forms as part of the body's natural healing process in response to injury or trauma. Epithelial tissue, cartilage, and adipose tissue are not typically involved in scar formation. Therefore, the correct answer is fibrous connective tissue, as it is the specific type of tissue that makes up scar tissue.