Nokea
What is represented by this formula: 6COâ‚‚ + 6Hâ‚‚O → C₆Hâ‚â‚‚O₆ + 6Oâ‚‚?
- A. Glycolysis
- B. Cellular respiration
- C. Photosynthesis
- D. Electronic transport
Correct Answer: C
Rationale: The formula represents the process of photosynthesis, where carbon dioxide (COâ‚‚) and water (Hâ‚‚O) are converted into glucose (C₆Hâ‚â‚‚O₆) and oxygen (Oâ‚‚) using light energy. This process is essential for plants and some microorganisms to produce food and oxygen. Glycolysis and cellular respiration involve breaking down glucose to produce energy, and the electron transport chain is part of cellular respiration, not photosynthesis.
You may also like to solve these questions
Which of these molecules contains glucose?
- A. Proteins
- B. Lipids
- C. Nucleic acids
- D. Carbohydrates
Correct Answer: D
Rationale: Glucose is a type of simple sugar and is classified as a carbohydrate. It is commonly found in various carbohydrate-containing foods such as fruits, vegetables, grains, and sugary snacks. Therefore, the molecule containing glucose would be a carbohydrate, making choice D the correct answer. Proteins (choice A) are made up of amino acids, lipids (choice B) are fats, and nucleic acids (choice C) are DNA and RNA, none of which contain glucose.
Which statement is untrue?
- A. RNA is single-stranded.
- B. RNA contains uracil.
- C. DNA codes for proteins.
- D. DNA cannot be altered.
Correct Answer: D
Rationale: DNA can be altered through various processes such as mutations, genetic engineering, and epigenetic modifications. Changes in DNA can occur naturally or through external influences, leading to variations in the genetic code. Therefore, the statement that DNA cannot be altered is untrue. Choices A, B, and C are true statements. RNA is indeed single-stranded, RNA contains uracil instead of thymine, and DNA serves as a template for protein synthesis.
Three students measured the mass of a product of combustion. They recorded measurements of 14 g, 16 g, and 17 g. If the known mass of the product is 30 g, how would you describe the students' measurements?
- A. Accurate
- B. Precise
- C. Both accurate and precise
- D. Neither accurate nor precise
Correct Answer: B
Rationale: The students' measurements are precise because they are consistently close to each other. However, they are not accurate because all the measurements deviate from the known mass of the product (30 g). Accuracy refers to how close a measurement is to the true or accepted value, while precision refers to the level of agreement among repeated measurements. Since the students' measurements are consistent but do not align with the true value, they can be considered precise but not accurate. Choice A is incorrect because accuracy relates to the proximity of the measurements to the true value, which is not the case here. Choice C is incorrect because although the measurements are precise, they are not accurate. Choice D is incorrect because the measurements are precise as they show good agreement with each other, even though they are not accurate.
A cell is in a solution in which the concentration of solutes is higher inside the cell than outside the cell. What would you expect to happen to the cell?
- A. It will swell and possibly burst.
- B. It will shrivel and shrink.
- C. It will maintain its current size.
- D. It will grow a supportive cell wall.
Correct Answer: A
Rationale: When a cell is in a solution where the concentration of solutes is higher inside the cell than outside, it is in a hypertonic environment. In this situation, water will move into the cell in an attempt to equalize the concentration of solutes on both sides of the cell membrane through the process of osmosis. As a result, the cell will swell as it takes in more water, potentially leading to bursting or cell lysis. Choice B is incorrect because a cell in a hypertonic solution will not shrivel and shrink due to water moving into the cell. Choice C is incorrect because the cell will not maintain its current size; it will swell. Choice D is incorrect because growing a supportive cell wall is not the immediate response to being in a hypertonic environment.
Why is yeast used to make bread rise?
- A. It engages in photosynthesis, which produces oxygen gas.
- B. Carbon dioxide forms while yeast carries out photosynthesis.
- C. Yeast carries out fermentation, producing ethanol and carbon dioxide.
- D. Yeast breathes in oxygen and produces carbon dioxide through aerobic respiration.
Correct Answer: C
Rationale: Yeast is used to make bread rise because it carries out fermentation, producing carbon dioxide gas. The carbon dioxide gas gets trapped in the dough, causing it to rise and create a fluffy texture in the bread. Choices A, B, and D are incorrect because yeast does not engage in photosynthesis, so it does not produce oxygen gas, does not carry out photosynthesis to form carbon dioxide, and does not produce carbon dioxide through aerobic respiration. Yeast's fermentation process is essential for bread rising.