Meiosis Flashcards

Questions and Answers

Where do our chromosomes come from?

Our parents

What happens during prophase 1 of meiosis 1?

Centrioles separate, spindle fibers are formed, nuclear envelope disappears, chromosomes become visible, tetrads form, crossing over takes place

What are tetrads?

Homologous chromosomes that associate with each other

What happens in metaphase 1 of meiosis 1?

Homologous chromosomes line up in the middle of the cell, spindle fibers attach onto the homologous chromosomes Signup and view all the answers

What happens in anaphase 1 of meiosis 1?

Spindle fibers help separate the homologous chromosomes Signup and view all the answers

What happens in telophase 1 in meiosis 1?

Nuclear envelope is reforming, cleavage furrow forms Signup and view all the answers

What is the number called when you start meiosis 1?

The diploid number Signup and view all the answers

What is the number called when you end with meiosis 1?

The haploid number Signup and view all the answers

What happens in prophase 2 of meiosis 2?

Nuclear envelope disappears, chromosomes condense, centrioles move apart and spindles start to form Signup and view all the answers

What happens in metaphase 2 of meiosis 2?

Chromosomes with sisters line up in the middle of the cell, spindle fibers attach onto chromatids Signup and view all the answers

What happens in anaphase 2 in meiosis 2?

The sister chromatids are separating by spindle fibers Signup and view all the answers

What happens in telophase 2 in meiosis 2?

4 separate cells are formed, chromosomes are unraveling, nuclear envelope reforms Signup and view all the answers

What is the significance of crossing over?

Creates genetic diversity in gametes Signup and view all the answers

What happens in crossing over?

Homologous chromosomes swap equal sections of chromosomes Signup and view all the answers

What is the difference between metaphase 1 in mitosis and metaphase 1 in meiosis?

In meiosis they are homologous chromosomes Signup and view all the answers

What is the main result of meiosis?

The number of chromosomes in the gamete goes from the diploid number to the haploid number allowing the sperm and egg to combine and have 46 chromosomes. The result is 4 genetically different haploid cells. Signup and view all the answers

What is the main difference between mitosis and meiosis?

Meiosis has 2 cell divisions Signup and view all the answers

What is a diploid?

A cell that contains both sets of homologous chromosomes Signup and view all the answers

What is a haploid?

A cell that contains only a single set of chromosomes Signup and view all the answers

Why don't you look like your siblings?

Because during anaphase 1 the homologous chromosomes separate and line up in a random order and crossing over creates genetic diversity. Signup and view all the answers

What is independently assortment?

When alleles for a particular trait get distributed randomly Signup and view all the answers

What is meiosis?

The process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell Signup and view all the answers

What is the result of meiosis vs. mitosis?

Mitosis results in the production of two genetically identical diploid cells. Meiosis produces four genetically different haploid cells. Signup and view all the answers

Study Notes

Chromosome Origins

Chromosomes are inherited from our parents, contributing to genetic diversity.

Meiosis Stages

Prophase 1: Centrioles separate, spindle fibers form, nuclear envelope disintegrates, chromosomes become visible, tetrads form, and crossing over occurs.
Tetrads: Formed by homologous chromosomes associating with each other during prophase 1.
Metaphase 1: Homologous chromosomes align at the cell's equator, with spindle fibers attaching to them.
Anaphase 1: Spindle fibers pull homologous chromosomes apart to opposite poles of the cell.
Telophase 1: Nuclear envelope reforms; cleavage furrow begins to develop.

Chromosome Counts

The starting point of meiosis 1 is the diploid number, whereas the end of meiosis 1 results in haploid cells.

Meiosis 2 Stages

Prophase 2: Nuclear envelope breaks down, chromosomes condense, centrioles move apart, and spindle formation resumes.
Metaphase 2: Chromosomes consisting of sister chromatids align at the cell's equator, with spindle fibers attaching to chromatids.
Anaphase 2: Sister chromatids are separated by spindle fibers and move to opposite poles.
Telophase 2: Four distinct haploid cells form; chromosomes decondense, and nuclear envelopes reform.

Genetic Diversity

Crossing Over: A key event allowing homologous chromosomes to exchange equal segments, enhancing genetic diversity in gametes.
Independent Assortment: The random distribution of alleles during gamete formation contributes to individual variation.

Comparisons

Metaphase Differences: In meiosis, homologous chromosomes line up in metaphase 1, while in mitosis, it involves sister chromatids.
Results of Meiosis vs. Mitosis: Meiosis leads to four genetically diverse haploid cells, while mitosis results in two genetically identical diploid cells.

Cellular Definitions

Diploid: Contains both sets of homologous chromosomes.
Haploid: Contains a single set of chromosomes.

Sibling Differences

Siblings can look different due to random separation of homologous chromosomes in anaphase 1 and crossing over, contributing to genetic diversity.

Purpose of Meiosis

The process reduces chromosome numbers by half through the separation of homologous chromosomes, crucial for the formation of gametes.

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Description

Test your knowledge of meiosis with these flashcards. Each card features key concepts such as chromosome origin, tetrad formation, and phases of meiosis. Perfect for students wanting to reinforce their understanding of this crucial biological process.