Question at position 34 During meiosis, cells replicate their DNA before meiosis I and replicate their DNA again before meiosis II.TrueFalseSingle choice
A
True
B
False

Question

Question at position 34 During meiosis, cells replicate their DNA before meiosis I and replicate their DNA again before meiosis II.TrueFalse

BlackTom AI · Accepted Answer

DNA replication occurs once before meiosis I (during the premeiotic S phase); there is no second round of replication before meiosis II.

Relevant knowledge points and concepts:
- Meiosis consists of one round of DNA replication followed by two successive nuclear divisions: meiosis I (reductional) and meiosis II (equational).
- During the S phase before meiosis I, each chromosome is duplicated into two sister chromatids held together by cohesin proteins.
- Meiosis I separates homologous chromosome pairs (reducing chromosome number from diploid to haploid), while meiosis II separates sister chromatids, similar to mitosis.
- The interval between meiosis I and II (interkinesis) lacks an S phase and therefore no DNA synthesis occurs.

Step-by-step reasoning:
1. A diploid germ cell enters premeiotic S phase and replicates its DNA → each chromosome becomes two sister chromatids (2n, duplicated).
2. Meiosis I (prophase I → metaphase I → anaphase I → telophase I): homologous chromosomes (each consisting of sister chromatids) are separated into two daughter cells. After cytokinesis the cells are haploid in chromosome number but still have replicated chromosomes (each chromosome = two sister chromatids).
3. Between meiosis I and II there is no S phase. Cells may undergo interkinesis, but DNA replication does not occur.
4. Meiosis II (prophase II → metaphase II → anaphase II → telophase II): sister chromatids are separated into individual chromosomes, producing four haploid cells with unreplicated chromosomes.

Why the correct answer is correct:
- Claiming a second DNA replication before meiosis II would double DNA content again and defeat the purpose of meiotic reduction; molecular regulation prevents this second S phase.

Why the other option (True) is incorrect:
- It contradicts the well-established sequence of one replication and two divisions; experimental and textbook evidence show no S phase between meiosis I and II.

Conclusion: The correct choice is False, which matches the provided answer.

Question at position 34 During meiosis, cells replicate their DNA before meiosis I and replicate their DNA again before meiosis II.TrueFalseSingle choice

Similar Questions

Expansionary fiscal policy in an open economy with a floating exchange rate will likely:

Contractionary monetary policy in an open economy with a floating exchange rate will likely:

Contractionary monetary policy in an open economy with a fixed exchange rate will likely ____ a trade surplus.

Which is expansionary monetary policy?

Which is contractionary fiscal policy?

Which is expansionary fiscal policy?

What would raise aggregate supply (AS)?

What would shift aggregate supply (AS) to the right?

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler