Mitosis and Its Stages

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Questions and Answers

What is the primary purpose of mitosis?

To produce gametes for reproduction

To replicate cellular organelles

To create genetic diversity

To ensure cells divide into two identical daughter cells (correct)

At the end of interphase, what form is the DNA in?

Chromosomes

Nucleotides

Chromatin (correct)

Spindles

What initiates the formation of the mitotic spindle during prophase?

Migration of centriole pairs to opposite ends (correct)

Replication of DNA

Breaking down of the nuclear envelope

Coalescing of DNA into chromatin

What structure connects two identical chromosomes during prophase?

Centromere Signup and view all the answers

Which cell types are produced by mitosis?

Only somatic cells Signup and view all the answers

What happens to the nuclear envelope during prophase?

It dissolves Signup and view all the answers

What is the role of microtubules in mitosis?

To guide chromosomes to opposite ends of the cell Signup and view all the answers

What occurs during prophase I of meiosis that is not seen in mitosis?

Crossing over Signup and view all the answers

How are the daughter cells produced at the end of meiosis I different from those produced at the end of mitosis?

Daughter cells in meiosis I contain two copies of the same half-set of directions. Signup and view all the answers

What is the main action that occurs during anaphase I of meiosis?

Homologous chromosomes are pulled to opposite ends. Signup and view all the answers

What is true about meiosis II compared to meiosis I?

Meiosis II includes the steps of prophase, metaphase, anaphase, and telophase. Signup and view all the answers

What describes the chromosome state of the cells at the end of meiosis I?

Each cell contains two almost identical versions of the same chromosome. Signup and view all the answers

What occurs at the end of prophase during mitosis?

Microtubules attach to the centromeres of chromosomes. Signup and view all the answers

During which phase of mitosis do chromosomes line up in the middle of the cell?

Metaphase Signup and view all the answers

What process begins during anaphase?

Separation of sister chromatids Signup and view all the answers

What occurs during telophase?

A membrane begins to form between the two poles. Signup and view all the answers

Which type of cell division is responsible for producing specialized cells for sexual reproduction?

Meiosis Signup and view all the answers

What does diploid mean in terms of chromosome sets?

Cells contain two copies of each chromosome. Signup and view all the answers

Which cells are referred to as haploid?

Gametes Signup and view all the answers

What is the primary difference between mitosis and meiosis?

Mitosis creates diploid daughter cells, meiosis creates haploid cells. Signup and view all the answers

What do chromosomes do during prophase of mitosis?

They condense and become denser. Signup and view all the answers

In plant cells, cytokinesis occurs differently than in animal cells because of:

The presence of a rigid cell wall. Signup and view all the answers

Study Notes

Mitosis

Mitosis is cell division, where one cell replicates its DNA to produce two identical daughter cells.
This process happens throughout the body, except for sperm and egg cells.
Mitosis occurs over 4 phases: prophase, metaphase, anaphase, and telophase.
Interphase precedes mitosis, and is the stage where DNA is replicated before the cell begins division.

Prophase

The replicated DNA condenses into chromosomes, which are tightly bound structures.
These chromosomes are bound together by a microtubule called the centromere.
Centrioles move to opposite ends of the cell and form the mitotic spindle, which comprises microtubules.
At the end of prophase, the nuclear envelope dissolves, and microtubules attach to the centromere of each chromosome.

Metaphase

Metaphase is where chromosomes align in the middle of the cell.
This occurs because the centromeres are attached to the mitotic spindle, pulling the chromosomes to the cell's center.
During this phase, the cell looks symmetrical, with the centriole pairs at opposite ends and the chromosomes lined up in the middle.
The alignment of chromosomes ensures their equal distribution to the two daughter cells.

Anaphase

Anaphase is the stage where the cell begins to pull itself apart.
Sister chromatids, held together by the centromere, separate and are pulled towards opposite poles of the cell.
This pulling action is driven by the microtubules of the spindle, which are attached to the centromere.

Telophase

During telophase, two daughter cells form.
A membrane forms between the ends of the cell, separating the cytoplasm.
Organelles migrate to opposite cell poles in a process called cytokinesis.
A new nuclear envelope forms around the chromosomes, and the chromosomes begin to unwind, returning to chromatin.
Telophase concludes with two identical daughter cells, ready to grow and divide.

Plant Cell Division Differences

Plant cells have a rigid cell wall which is why cytokinesis occurs from within the cell.
Plant cells don't have centrioles.
Cell plates form between the cells, eventually creating a new cell wall.

Meiosis

Responsible for the production of specialized cells for sexual reproduction.
Meiosis combines genetic material from two organisms to create new organisms with different genetic combinations.

Somatic Cells vs. Gametes

Somatic cells (normal body cells) are diploid (2n), meaning they have two copies of each gene, inherited from both parents.
Gametes (sex cells, like sperm and egg), are haploid (n) – they contain only half the number of chromosomes needed to form a new organism.
When two gametes combine (fertilization), they form a diploid zygote, which gives rise to a new organism.

Meiosis I and II

Meiosis involves two rounds of division: Meiosis I and Meiosis II.
Meiosis I is a more complex process than mitosis and involves recombination or crossing-over of DNA, which mixes genetic material.
In Meiosis I, sister chromatids remain attached, and each daughter cell gets a complete set of chromosomes, but only half the genetic information.
Meiosis II is similar to mitosis, but DNA is not replicated before it begins and the sister chromatids get separated, resulting in four haploid daughter cells which are gametes.

Key Takeaways

Mitosis is cell division that produces identical daughter cells, while meiosis produces haploid gametes for sexual reproduction.
Mitosis is essential for growth and repair, while meiosis is crucial for genetic diversity.

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Description

Explore the fascinating process of mitosis, where a single cell divides to create two identical daughter cells. This quiz covers the four key stages: prophase, metaphase, anaphase, and telophase, along with the essential preparations of interphase. Test your understanding of each phase and its significance in the cell cycle.