At the beginning of meiosis, how many chromosomes does the diploid parent cell have?
- A. 23
- B. 24
- C. 46
- D. 54
Correct Answer: C
Rationale: The correct answer is C: 46. At the start of meiosis, the diploid parent cell contains 46 chromosomes. During meiosis, the number of chromosomes is halved, resulting in each gamete having 23 chromosomes. Choice A (23) is incorrect because that is the number of chromosomes in a human gamete, not the parent cell. Choice B (24) and Choice D (54) are also incorrect as they do not reflect the correct number of chromosomes in a diploid parent cell at the beginning of meiosis.
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Binary fission is a type of asexual reproduction. Which of the following occurs during the binary fission process?
- A. The chromosomes bind to the plasma membrane
- B. The chromosomes attach to the spindle formed along the axis
- C. The chromosomes gather in the center of the cell
- D. The chromosomes begin to separate
Correct Answer: A
Rationale: The correct answer is A. In binary fission, the chromosomes bind to the plasma membrane before the cell splits into two. This initial step ensures that each daughter cell receives a complete set of genetic material. Choice B is incorrect because the spindle apparatus is characteristic of eukaryotic cell division (mitosis), not prokaryotic binary fission. Choice C is incorrect as chromosomes do not necessarily gather in the center of the cell during binary fission. Choice D is incorrect because the chromosomes do not begin to separate in binary fission; they replicate and then move to opposite ends of the cell before division.
Which of the following options is the term used to represent alternative versions of a gene?
- A. Alleles
- B. Binary fission
- C. Heterozygous
- D. Homozygous
Correct Answer: A
Rationale: The correct answer is A: Alleles. Alleles are different forms of a gene that can exist at a specific locus on a chromosome. They represent variations in a gene's DNA sequence. Choices B, C, and D are incorrect. Binary fission is a form of asexual reproduction in single-celled organisms, while heterozygous and homozygous refer to different combinations of alleles in an individual, not the alternative versions of a gene.
During photosynthesis in green plants, light energy is captured and used to convert all except which of the following into oxygen and energy-rich organic compounds?
- A. Minerals
- B. Water
- C. Carbon dioxide
- D. Metals
Correct Answer: D
Rationale: During photosynthesis in green plants, light energy is utilized to convert water and carbon dioxide into oxygen and energy-rich organic compounds like glucose. Minerals play a role in plant growth but are not directly converted during photosynthesis. Metals are not part of the photosynthesis process, making them the correct answer. Therefore, the correct choice is D. Choices A, B, and C are incorrect as minerals, water, and carbon dioxide are involved in the photosynthesis process.
The term pleiotropy is best defined as which of the following?
- A. A situation in which one gene remains unexpressed
- B. One gene influencing multiple, seemingly unrelated phenotypic traits
- C. Two genes affected by a single allele
- D. A condition in which multiple genes are missing
Correct Answer: B
Rationale: Pleiotropy is best defined as one gene influencing multiple, seemingly unrelated phenotypic traits. This phenomenon showcases the multifunctionality of genes, where a single gene can have effects on various aspects of an organism's phenotype. Choices A, C, and D do not accurately capture the concept of pleiotropy. Option A refers to gene expression, not pleiotropy. Option C describes genetic interactions but not in the context of pleiotropy. Option D talks about missing genes, which is unrelated to the definition of pleiotropy.
In which of the following does cellular respiration take place?
- A. Golgi apparatus
- B. Mitochondrion
- C. Chloroplast
- D. Ribosome
Correct Answer: B
Rationale: The correct answer is B, Mitochondrion. Cellular respiration occurs in the mitochondria, where glucose is converted into energy through a series of metabolic processes. Choice A, Golgi apparatus, is incorrect as it is involved in modifying, sorting, and packaging proteins. Choice C, Chloroplast, is incorrect as it is the site of photosynthesis in plant cells, not cellular respiration. Choice D, Ribosome, is incorrect as it is responsible for protein synthesis, not energy production through cellular respiration.