Meiosis II Phases

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Questions and Answers

What is the primary event that occurs during Prophase II of meiosis?

Cytoplasm divides, and nuclear membrane reforms.

Spindle fibers attach to chromatids at the kinetochores.

Chromatids move towards each pole of the cell.

Chromosomes condense to form metaphase chromosomes. (correct)

In which stage of meiosis II does the cytoplasm divide?

Anaphase II

Cytokinesis (correct)

Metaphase II

Telophase II

During Metaphase II of meiosis, what is the primary alignment of chromosomes?

Chromosomes line up randomly.

Chromosomes line up at the poles.

Chromosomes do not line up at all.

Chromosomes line up at the equatorial plane. (correct)

What is the primary event that occurs during Telophase II of meiosis?

Single-stranded chromosomes decondense. Signup and view all the answers

In which stage of meiosis II do the sister chromatids separate?

Anaphase II Signup and view all the answers

What is the result of meiosis II in terms of the number of daughter cells formed?

Four haploid daughter cells Signup and view all the answers

What is the primary function of Prophase I?

Condensation of chromatin into chromosomes Signup and view all the answers

What occurs during Anaphase I?

Spindle fibers begin to contract and separate the bivalent or tetrads Signup and view all the answers

During which stage of meiosis do spindle fibers from the centrosomes of each pole connect to bivalents or tetrads?

Metaphase I Signup and view all the answers

What occurs during Telophase I?

Chromosomes decondense and nuclear membranes reform Signup and view all the answers

When does Cytokinesis or the cytoplasmic division occur during meiosis?

During Telophase I Signup and view all the answers

What is the result of meiosis in terms of the number of chromosomes in gametes?

The number of chromosomes decreases by half Signup and view all the answers

What is the result of the separation of genetically identical sister chromatids during Anaphase?

The movement of single chromatids towards opposite poles Signup and view all the answers

What happens to the nuclear membrane during Metaphase?

It breaks down Signup and view all the answers

What is the stage of cell division where the chromosomes are at the opposing poles of the spindle?

Telophase Signup and view all the answers

What occurs concurrently with karyokinesis during Telophase?

Cytokinesis Signup and view all the answers

What is the outcome of cytokinesis in animal cells?

The formation of cleavage furrows that separate the cell Signup and view all the answers

What is the result of Mitosis?

The formation of two identical daughter cells Signup and view all the answers

Study Notes

Meiosis

Meiosis involves two divisions: Meiosis I and Meiosis II, resulting in four haploid daughter cells.
Human somatic cells have 46 chromosomes, but reproductive cells (gametes) have 23 chromosomes, due to meiosis reducing the chromosome number by half.

Phases of Meiosis I

Prophase I: longest phase, comprising five sub-phases: condensation of chromatin into chromosomes, physical contact between homologous chromosomes, and transmission of genetic information between synapsed chromosomes.
Metaphase I: spindle fibers connect to bivalents through kinetochores, and homologous chromosomes line up at the equatorial plane, with double alignment of chromosomes.
Anaphase I: spindle fibers contract, separating bivalent or tetrads, and homologous chromosomes migrate to each pole of the cell.
Telophase I: chromosomes decondense, nuclear membranes reform, and cytokinesis occurs, forming two haploid daughter cells with 23 chromosomes.

Phases of Meiosis II

Prophase II: chromosomes condense, nuclear membrane dissolves, and centrosomes move towards each pole of the cell.
Metaphase II: spindle fibers attach to chromatids, and chromosomes line up at the equatorial plane (single alignment).
Anaphase II: spindle fibers shorten, separating sister chromatids, which move towards each pole of the cell.
Telophase II: single-stranded chromosomes decondense, nuclear membrane and nucleolus reform, and cytoplasm divides, forming four haploid daughter cells.

Chromosomal Aberrations

Chromosomal aberrations are disorders characterized by morphological or numerical alterations in single or multiple chromosomes, affecting autosomes, sex chromosomes, or both.
Types of chromosomal aberrations include:
Gene Deficiency or Deletion: a mutation in which a part of a chromosome or a sequence of DNA is left out during DNA replication.
Gene Duplication: a mutation in which a sequence of genetic information is duplicated.
Translocation: a genetic change in which a piece of one chromosome breaks off and attaches to another chromosome.

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Description

Learn about the stages of Meiosis II, including Prophase II, Metaphase II, and Anaphase II. Understand the processes of chromosome condensation, spindle fiber attachment, and chromosome separation. Test your knowledge of the second meiotic division!