Meiosis Test Part Two: Steps Of Meiosis I And Meiosis II Flashcards Preview

Biology > Meiosis Test Part Two: Steps Of Meiosis I And Meiosis II > Flashcards

Flashcards in Meiosis Test Part Two: Steps Of Meiosis I And Meiosis II Deck (14):
1

Meiosis

A process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

2

Prophase I

Each replicated chromosome pairs with its corresponding homologous chromosome

Pairing forms a structure called a tetrad, which contains 4 chromatids

As homologous chromosomes form tetrads, they undergo the process of crossing over

The chromatids of the homologous chromosomes cross over each other. The crossed sections of the chromatids are then exchanged. Produces new variations of alleles in the cell - genes

Spindle forms and attaches to each tetrad

3

Crossing over

The chromatids of the homologous chromosomes cross over each other. The crossed sections of the chromatids are then exchanged. Produces new variations of alleles in the cell - genes

4

Metaphase I

Paired homologous chromosomes line up across the center of the cell

5

Anaphase I

Spindle fibers pull each homologous chromosome pair toward opposite ends of the cell
SISTER CHROMOSOMES DO NOT SEPARATE
Separated chromosomes cluster at opposite ends of the cell

6

Telophase I and cytokinesis

A nuclear membrane forms around each cluster of chromosomes. Cytokinesis (the division of the cell's cytoplasm) follows, forming two new cells

7

Meiosis I results in

Two daughter cells.
Because each pair of homologous chromosomes was separated, neither daughter cell has two complete sets of chromosomes (unlike a diploid cell)

The daughter cells have sets of chromosomes and alleles different from each other and from the diploid cell that entered meiosis I

8

Prophase II

The cells chromosomes - each consisting of 2 chromatids - become visible.
Chromosomes do not pair for tetrads, homologous chromosomes were already separated during meiosis I

9

Metaphase II

Chromosomes line up at the center of each cell

10

Anaphase II

Paired chromatids separate

11

Telophase II and cytokinesis

Nuclear envelope forms, cytoplasm separates. Results in four haploid daughter cells

12

Last four phases of meiosis II

Similar to those in meiosis I, however, the result is four haploid daughter cells
Each of the four daughter cells have two (haploid) chromosomes after meiosis II, from the original 4 chromosomes (diploid)

13

Main differences between meiosis and mitosis

Replication and separation of genetic material
Changes in chromosome number
Number of cell divisions

14

Similarities between meiosis and mitosis

Mitosis and meiosis are both types of cell division that occur in humans and other animals. They share the production of new cells and replication of genetic material