Mitosis and Meiosis Overview

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Questions and Answers

What is the primary purpose of meiosis?

Asexual reproduction

Growth and repair

Sexual reproduction (correct)

Cell cycle regulation

How many divisions occur during meiosis?

2 (correct)

What is the result of meiosis in terms of the number of cells produced?

4 (correct)

Which of the following statements is accurate regarding genetic variation in meiosis?

Meiosis allows for genetic variation through crossing over and independent assortment. (A) Signup and view all the answers

At the end of meiosis, what is the chromosome number of the cells produced?

Haploid (n) (B) Signup and view all the answers

What occurs during Anaphase I of meiosis?

Homologous chromosomes are pulled to opposite poles. (A) Signup and view all the answers

What is the main purpose of independent assortment during meiosis?

To create genetic variation among gametes. (C) Signup and view all the answers

What is produced at the end of Telophase II and Cytokinesis in meiosis?

Four genetically unique haploid cells. (D) Signup and view all the answers

Which stage of meiosis does DNA replication not occur after?

Telophase I (C) Signup and view all the answers

What is a key difference between meiosis and mitosis regarding the outcome of cell division?

Mitosis results in diploid cells while meiosis results in haploid cells. (C) Signup and view all the answers

Which phase of the cell cycle is the longest?

Interphase (D) Signup and view all the answers

What major event occurs during prophase?

Nuclear envelope breaks down (C) Signup and view all the answers

During which stage do spindle fibers attach to the centromeres of chromosomes?

Metaphase (A) Signup and view all the answers

What happens during the anaphase of mitosis?

Sister chromatids are pulled apart to opposite ends (D) Signup and view all the answers

Which sub-phase of interphase involves DNA replication?

Synthesis (C) Signup and view all the answers

What structure forms to help guide chromosomes during mitosis?

Spindle fibers (B) Signup and view all the answers

What is the final result of mitosis and cytokinesis?

Two identical daughter cells (A) Signup and view all the answers

What key event occurs during the checkpoint before anaphase?

Ensuring all chromosomes are attached to spindle fibers (C) Signup and view all the answers

What happens to sister chromatids during anaphase?

They are pulled apart to opposite poles (B) Signup and view all the answers

In which stage do chromosomes become less compact and revert to chromatin?

Telophase (A) Signup and view all the answers

How do animal cells achieve cytokinesis?

Pinching of the cell membrane by a contractile ring (C) Signup and view all the answers

What is a primary outcome of meiosis?

Reduction of chromosome number by half (C) Signup and view all the answers

Crossing over occurs in which stage of meiosis?

Prophase I (D) Signup and view all the answers

Which of the following statements about mitosis and meiosis is true?

Mitosis results in identical daughter cells. (D) Signup and view all the answers

Study Notes

Mitosis and Meiosis

Mitosis is a cell division process that produces two identical nuclei. It's used for growth, repair, and asexual reproduction.
Meiosis is a cell division process that produces four genetically unique haploid cells (like sperm and egg cells). It's used for sexual reproduction and introduces diversity.

Stages of Mitosis

Interphase: The cell spends most of its life here, DNA replicates and the cell grows.
Prophase: Chromosomes condense, the nuclear membrane disappears, and spindle fibers form.
Metaphase: Chromosomes line up in the middle of the cell.
Anaphase: Sister chromatids are pulled apart to opposite ends of the cell.
Telophase: New nuclear membranes form around each set of chromosomes and the cell begins to divide.
Cytokinesis: The cell membrane pinches in and divides into two daughter cells. (This happens after Telophase).

Stages of Meiosis I

Prophase I: Chromosomes condense and homologous chromosomes pair up to form tetrads. Crossing over occurs.
Metaphase I: Homologous chromosome pairs line up at the metaphase plate. Independent assortment occurs.
Anaphase I: Homologous chromosomes are pulled to opposite poles. Sister chromatids stay attached.
Telophase I and Cytokinesis: The nuclear envelope may reform, the cell divides forming two haploid daughter cells.

Stages of Meiosis II

Prophase II: Chromosomes condense again and the nuclear membrane breaks down. Spindle fibres form.
Metaphase II: Chromosomes line up at the metaphase plate. Spindle fibers attach to centromeres.
Anaphase II: Sister chromatids are pulled apart to opposite poles.
Telophase II and Cytokinesis: Four genetically unique haploid cells result. Nuclear envelopes reform, and the cells divide.

Key Differences Between Mitosis and Meiosis

Feature	Mitosis	Meiosis
Purpose	Growth, repair, asexual reproduction	Sexual reproduction
Number of Divisions	1	2
Number of Cells Produced	2	4
Genetic Variation	No	Yes (crossing over and independent assortment)
Chromosome Number	Diploid (2n) → Diploid (2n)	Diploid (2n) → Haploid (n)

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Description

This quiz covers the processes of mitosis and meiosis, including their stages and functions. Understand how these cell division mechanisms contribute to growth, repair, and reproduction. Test your knowledge on the differences between these two processes and their significance in living organisms.