If the DNA content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of the same cell at metaphase of meiosis I will be
a. 0.25x
b. 0.5x
c. x
d. 2x

검증된 단계별 안내

Understand the cell cycle phases: In the G1 phase, the cell is diploid with a DNA content of x. During the S phase, DNA replication occurs, doubling the DNA content to 2x.

Recognize the stages of meiosis: Meiosis consists of two divisions, meiosis I and meiosis II. Meiosis I is where homologous chromosomes are separated.

Focus on metaphase of meiosis I: At this stage, the cell has completed DNA replication, so the DNA content is still 2x, but homologous chromosomes are aligned at the metaphase plate.

Consider the chromosome number: Although the DNA content is 2x, the cell is preparing to divide into two cells, each with a haploid set of chromosomes.

Conclude the DNA content at metaphase of meiosis I: Since the DNA has been replicated but not yet divided, the DNA content remains at 2x during metaphase of meiosis I.

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45s

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Cell Cycle Phases

The cell cycle consists of stages that a cell goes through to divide and replicate. G1 phase is the first gap phase where the cell grows and prepares for DNA replication. Understanding the DNA content during different phases, such as G1 and metaphase, is crucial for determining changes in DNA quantity during cell division processes like meiosis.

Meiosis I

Meiosis I is the first division in meiosis, where homologous chromosomes are separated into two daughter cells. During metaphase I, chromosomes align at the metaphase plate, and the cell is still diploid, containing two sets of chromosomes. This phase is essential for understanding how DNA content changes as cells prepare to divide.

DNA Content in Meiosis

DNA content changes during meiosis as cells undergo division. In the G1 phase, a diploid cell has a DNA content of x. By metaphase of meiosis I, the cell has duplicated its DNA during the preceding S phase, resulting in a DNA content of 2x, as homologous chromosomes are paired but not yet separated.