Nokea
What is the 3D structure of a protein called?
- A. Tertiary structure
- B. Secondary structure
- C. Primary structure
- D. Quaternary structure
Correct Answer: A
Rationale: - Primary structure refers to the linear sequence of amino acids in a protein.
- Secondary structure refers to local folded structures within a protein, such as alpha helices and beta sheets.
- Tertiary structure is the overall 3D shape of a protein, which is determined by interactions between amino acid side chains and the environment.
- Quaternary structure refers to the arrangement of multiple protein subunits in a protein complex.
Therefore, the 3D structure of a protein is called the tertiary structure because it represents the overall folding of the protein into a specific shape.
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Which of the following terms refers to a muscle twitch, a single forceful contraction of a muscle fiber?
- A. Tetanus
- B. Tremor
- C. Fasciculation
- D. Rigidity
Correct Answer: C
Rationale: The correct term for a muscle twitch, a single forceful contraction of a muscle fiber, is 'Fasciculation' (choice C). Fasciculation specifically describes this phenomenon. 'Tetanus' (choice A) refers to sustained muscle contraction, 'Tremor' (choice B) indicates a shaky or quivering movement, and 'Rigidity' (choice D) denotes stiffness or inflexibility in muscles. Therefore, choices A, B, and D are incorrect in the context of a single forceful contraction of a muscle fiber.
Which layer of the skin, containing connective tissue, blood vessels, and nerve endings, is located beneath the epidermis?
- A. Epidermis
- B. Dermis
- C. Hypodermis
- D. Stratum corneum
Correct Answer: B
Rationale: The correct answer is the dermis. The dermis is the deeper layer of the skin that contains connective tissue, blood vessels, and nerve endings. It is located beneath the epidermis and provides structural support, nourishment, and sensitivity to the skin. The epidermis is the outermost layer of the skin responsible for protection. The hypodermis, also known as the subcutaneous layer, is the deepest layer that contains fat cells and plays a role in insulation and energy storage. The stratum corneum is the outermost layer of the epidermis composed of dead skin cells that are continually shed and replaced.
What functional group is present in ethers?
- A. Hydroxyl
- B. Carbonyl
- C. Ether
- D. Amine
Correct Answer: C
Rationale: The functional group present in ethers is -O-, representing an oxygen atom bonded to two alkyl or aryl groups. Therefore, choice C, 'Ether,' is the correct answer. Choices A, B, and D refer to different functional groups: hydroxyl (-OH), carbonyl (C=O), and amine (NH2), respectively, which are not present in ethers. Ethers are characterized by the oxygen atom bonded to two carbon groups, distinguishing them from the other functional groups mentioned in the choices.
What is the process of cells restoring damaged or lost tissues called?
- A. Cell division
- B. Cell differentiation
- C. Cell growth
- D. Cell regeneration
Correct Answer: D
Rationale: Rationale:
A) Cell division refers to the process by which a cell divides into two daughter cells.
B) Cell differentiation is the process by which cells become specialized for specific functions.
C) Cell growth is the increase in cell size or number.
D) Cell regeneration is the process of cells restoring damaged or lost tissues by replacing or repairing the damaged cells. This process is essential for healing wounds and maintaining tissue integrity.
Which part of the brain is responsible for balance and coordination?
- A. Cerebellum
- B. Cerebrum
- C. Hypothalamus
- D. Thalamus
Correct Answer: A
Rationale: The correct answer is the cerebellum. It plays a vital role in balance and coordination by controlling motor functions, precision, and timing of movements. The cerebrum is primarily involved in higher brain functions such as thinking and problem-solving. The hypothalamus regulates essential bodily functions like temperature and hunger, while the thalamus serves as a relay station for sensory information, directing it to the appropriate areas of the brain for processing.