Nokea
Which transport mechanism uses vesicles to move materials out of the cell?
- A. Endocytosis
- B. Active transport
- C. Diffusion
- D. Exocytosis
Correct Answer: D
Rationale: Exocytosis is the transport mechanism that uses vesicles to move materials out of the cell. Vesicles carry substances to the cell membrane, fuse with it, and release their contents outside the cell. This process is essential for secreting molecules such as hormones, enzymes, or neurotransmitters. Endocytosis, on the other hand, is the process of bringing materials into the cell by engulfing them in vesicles. Active transport involves the movement of molecules across a cell membrane against their concentration gradient, requiring energy. Diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration.
You may also like to solve these questions
Which of the following is a unit of power?
- A. Newton-meter (N·m)
- B. Joule (J)
- C. Watt (W)
- D. Kilogram (kg)
Correct Answer: C
Rationale: The correct answer is C: Watt (W). Power is the rate at which work is done or energy is transferred. The unit of power is the watt (W), named after James Watt, the inventor of the steam engine. A Newton-meter (N·m) is a unit of torque, Joule (J) is a unit of energy, and Kilogram (kg) is a unit of mass, not power. Therefore, choices A, B, and D are incorrect as they represent units of torque, energy, and mass, respectively, and not power.
Which structure allows for the selective passage of materials into and out of the cell?
- A. DNA
- B. Protein
- C. Carbohydrate
- D. Phospholipid bilayer
Correct Answer: D
Rationale: The phospholipid bilayer is a crucial component of the cell membrane, surrounding the cell and regulating the passage of materials into and out of the cell. Its structure enables it to be selectively permeable, controlling which substances can pass through. DNA, proteins, and carbohydrates are essential molecules in the cell but do not directly govern the passage of materials like the phospholipid bilayer does. Therefore, the correct answer is the phospholipid bilayer.
What is the process of converting ammonia, a byproduct of protein digestion, into a less toxic form?
- A. Deamination
- B. Transamination
- C. Decarboxylation
- D. Hydrolysis
Correct Answer: A
Rationale: Deamination is the correct answer. It is the process of removing an amino group from a molecule, like converting ammonia (NH3) into a less toxic form such as urea. Ammonia, a byproduct of protein digestion, must be converted into a less toxic form for excretion. Deamination is a crucial step that mainly occurs in the liver through the urea cycle. Transamination involves transferring an amino group from one molecule to another, not removing it as in deamination. Decarboxylation is the removal of a carboxyl group from a molecule, and hydrolysis is the breakdown of a compound by adding water.
Which skin condition is characterized by red, itchy, and inflamed patches?
- A. Eczema
- B. Psoriasis
- C. Melanoma
- D. Keloid
Correct Answer: A
Rationale: Eczema is a skin condition characterized by red, itchy, and inflamed patches. It is a common condition that can vary in severity and often presents with symptoms such as dry, scaly skin, and sometimes oozing or crusting. Psoriasis, on the other hand, presents with red, scaly patches but is not typically described as itchy. Melanoma is a type of skin cancer characterized by the development of abnormal moles, while keloid is a type of raised scar that can occur after an injury to the skin. Therefore, the correct answer is eczema due to its specific symptom presentation of red, itchy, and inflamed patches.
Why does a prism separate white light into its constituent spectral components?
- A. It absorbs certain colors
- B. Different colors experience varying speeds within the prism
- C. It bends all colors with the same magnitude
- D. It reflects specific colors
Correct Answer: B
Rationale: A prism separates white light into its constituent spectral components because different colors experience varying speeds within the prism due to their different wavelengths. This causes the light to refract at different angles, resulting in the separation of colors. When light enters the prism, it undergoes dispersion, where different colors are refracted at different angles due to their unique wavelengths. This phenomenon is known as chromatic dispersion. Choice A is incorrect because a prism does not absorb colors but refracts and disperses them. Choice C is incorrect because a prism refracts different colors at different angles, not with the same magnitude. Choice D is incorrect because a prism does not reflect colors but refracts and disperses them based on their wavelengths.