Nokea
The sum of all chemical reactions that occur in an organism is:
- A. product
- B. respiration
- C. metabolism
- D. synthesis
Correct Answer: C
Rationale: Metabolism is the sum of all chemical reactions that occur within an organism to maintain life. It involves all the processes that break down molecules to release energy (catabolism) and build new molecules to support growth and maintenance (anabolism). Respiration refers specifically to the process of generating energy from the breakdown of glucose molecules. Synthesis is the creation of complex molecules from simpler ones. Therefore, metabolism is the most comprehensive term that encompasses all these processes within an organism.
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Which type of passive transport uses proteins that change shape to move a target molecule through the membrane?
- A. Diffusion
- B. Carrier proteins
- C. Channel proteins
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B: Carrier proteins. Carrier proteins are involved in facilitated diffusion, a type of passive transport where specific target molecules are moved across the membrane with the help of proteins that change shape. These carrier proteins bind to the target molecule on one side of the membrane, undergo a conformational change, and then release the molecule on the other side. This process is crucial for the selective transport of certain molecules that cannot pass through the membrane by simple diffusion. Choices A and C are incorrect because diffusion and channel proteins do not involve proteins that change shape to transport target molecules selectively. Choice D is incorrect as carrier proteins fit the description provided in the question.
Where can epithelial tissue be found?
- A. Organ lining
- B. Heart muscle
- C. Tendons
- D. Spinal cord
Correct Answer: A
Rationale: Epithelial tissue is primarily found lining the surfaces of organs, such as the skin and the linings of various internal organs like the digestive tract, respiratory tract, and blood vessels. It serves as a protective barrier and helps with absorption and secretion. Heart muscle is made up of cardiac muscle tissue, tendons are primarily composed of dense connective tissue, and the spinal cord is composed of nervous tissue, none of which are classified as epithelial tissue.
The procedure to focus an image using a compound microscope involves
- A. Adjusting the coarse adjustment each time a new magnification is selected
- B. Adjusting the fine adjustment each time a new magnification is selected
- C. Adjusting the stage each time a new magnification is selected
- D. All of the above
Correct Answer: B
Rationale: When using a compound microscope, it is essential to adjust the fine adjustment knob each time you switch to a new magnification level. The fine adjustment knob allows for precise focusing on the specimen at different magnifications, ensuring a clear and sharp image. The coarse adjustment knob is typically used only at the lower magnification settings to bring the image into view roughly. Adjusting the stage may be necessary based on the size and thickness of the specimen, but it does not need to be done every time a new magnification is selected. Therefore, option B is the correct choice as it focuses on the key aspect of precise focusing during magnification changes.
In order, from lower to upper, the layers of the atmosphere are:
- A. Exosphere, thermosphere, mesosphere, stratosphere, troposphere
- B. Troposphere, stratosphere, mesosphere, thermosphere, exosphere
- C. Mesosphere, troposphere, stratosphere, thermosphere, exosphere
- D. Thermosphere, troposphere, stratosphere, mesosphere, exosphere
Correct Answer: B
Rationale: The correct order of the layers of the atmosphere, from lower to upper, is troposphere, stratosphere, mesosphere, thermosphere, exosphere. The troposphere is the lowest layer where weather phenomena occur. The stratosphere contains the ozone layer, which absorbs and scatters the solar ultraviolet radiation. The mesosphere is where most meteorites burn up upon entering the Earth's atmosphere. The thermosphere is characterized by high temperatures due to the absorption of solar radiation. The exosphere is the outermost layer where the atmosphere transitions into space. Therefore, option B is the correct sequence, as it reflects the ascending order of the Earth's atmospheric layers.
Which, if any, of the following statements are true?
- A. Water boils at approximately 100°C (212°F) at standard atmospheric pressure
- B. The boiling point is the temperature at which the vapor pressure is higher than the atmospheric pressure around the water
- C. Water boils at a lower temperature in areas of lower pressure
- D. A and C are true
Correct Answer: D
Rationale: Both statements A and C are true. Water indeed boils at approximately 100°C (212°F) at standard atmospheric pressure. However, water boils at a lower temperature in areas of lower pressure due to the decreased atmospheric pressure, which affects the vapor pressure and boiling point of water. Statement B is incorrect because the boiling point is the temperature at which the vapor pressure equals the external pressure (atmospheric pressure in this case), not when it is higher.