Nokea
Which organelle is the site of energy production?
- A. Mitochondrion
- B. Vacuole
- C. Cell membrane
- D. Ribosome
Correct Answer: A
Rationale: The correct answer is A: Mitochondrion. The mitochondrion is the site of energy production in a cell. It is often referred to as the powerhouse of the cell because it is where cellular respiration occurs, generating energy in the form of adenosine triphosphate (ATP) through processes like the citric acid cycle and oxidative phosphorylation. The other organelles listed play different roles in the cell - vacuoles store materials, the cell membrane regulates the movement of substances in and out of the cell, and ribosomes are involved in protein synthesis.
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Whose energy efficiency is greater?
- A. Herbivore
- B. Carnivore
- C. Omnivore
- D. Decomposer
Correct Answer: D
Rationale: Decomposers have the greatest efficiency of energy among the given options. Decomposers break down organic matter, such as dead plants and animals, into simpler substances through the process of decomposition. This breakdown process results in the release of nutrients back into the ecosystem, making energy more readily available for other organisms to use. In contrast, herbivores, carnivores, and omnivores all derive their energy from the consumption of other living organisms, making their energy efficiency lower than that of decomposers. Herbivores consume plants for energy, which involves energy loss due to inefficiencies in converting plant matter into usable energy. Carnivores consume herbivores or other carnivores, leading to further energy loss through each trophic level. Omnivores consume both plant and animal matter, but their energy efficiency is still lower than decomposers because of the energy loss associated with consuming living organisms. Decomposers play a crucial role in recycling nutrients and energy in ecosystems, making them highly efficient in the utilization of energy.
Which is not one of the raw materials needed for cellular respiration?
- A. ADP
- B. Phosphate
- C. Water
- D. Glucose
Correct Answer: C
Rationale: Water is not one of the raw materials needed for cellular respiration. The essential raw materials for cellular respiration include glucose (which is broken down to produce energy), oxygen, and ADP (adenosine diphosphate) and phosphate (which are necessary for the formation of ATP, the energy currency of cells). While water is crucial for many cellular processes and makes up a significant portion of cells, it is not directly involved as a raw material in the cellular respiration process.
In which phase of mitosis do new nuclear membranes form around sets of chromosomes?
- A. Prophase
- B. Anaphase
- C. Telophase
- D. Interphase
Correct Answer: C
Rationale: The correct answer is C, Telophase. During telophase, the final phase of mitosis, new nuclear membranes form around sets of chromosomes at the opposite poles of the cell. This process marks the completion of nuclear division in mitosis. Choices A, B, and D are incorrect because in prophase, chromosomes condense but nuclear membranes are not formed; in anaphase, chromosomes separate and move to opposite poles but no new nuclear membranes are formed; and in interphase, the cell prepares for division but nuclear membranes are not forming around sets of chromosomes.
Which names a final step in protein synthesis?
- A. DNA unzips.
- B. Amino acids bond.
- C. Transfer RNA bonds to messenger RNA.
- D. Messenger RNA moves to ribosomes.
Correct Answer: B
Rationale: The final step in protein synthesis is when amino acids bond together to form a protein chain. This process occurs during translation, where transfer RNA (tRNA) brings specific amino acids to the ribosome, and the ribosome catalyzes the formation of peptide bonds between the amino acids. This step ultimately leads to the synthesis of a complete protein based on the instructions from messenger RNA (mRNA).
Choice A ('DNA unzips') is incorrect as it refers to the initiation of transcription, not the final step of protein synthesis. Choice C ('Transfer RNA bonds to messenger RNA') is incorrect as it describes the process of translation initiation rather than the final step. Choice D ('Messenger RNA moves to ribosomes') is also incorrect as mRNA is already present at the ribosomes throughout the translation process, not just in the final step.
___________ is a symbiotic relationship in which one organism benefits and the other is not affected.
- A. Mutualism
- B. Parasitism
- C. Commensalism
- D. Competition
Correct Answer: C
Rationale: The correct answer is 'Commensalism.' In commensalism, one organism benefits from the relationship while the other is neither helped nor harmed. This type of symbiotic relationship is characterized by one organism deriving a benefit, such as food or shelter, without impacting the other organism in any significant way.
Choice A, 'Mutualism,' is a symbiotic relationship in which both organisms benefit. Choice B, 'Parasitism,' is a symbiotic relationship in which one organism benefits at the expense of the other. Choice D, 'Competition,' refers to a relationship in which organisms compete for limited resources, with both being affected in terms of access to resources.