Meiosis Flashcards
1
Q
What are the stages of meiosis? (Just name!)
A
Prophase 1
Metaphase 1
Anaphase 1
Telophase 1 and cytokinesis
Prophase 2
Metaphase 2
Anaphase 2
Telophase 2 and cytokinesis
2
Q
What is meiosis?
A
- cell division that creates 4 gametes (sperm or egg cells) that are genetically different
- each gamete contains 1/2 the total # of chromosomes = 23 chromosomes in total
- occurs in testes and ovarles
3
Q
The 2 stages of meiosis:
A
- meiosis 1: homologous chromosomes are separated
- meiosis 2: sister chromatids are separated
(At the end of meiosis, 4 haploid cells with genetic diversity are created).
4
Q
What happens in the end? (Meiosis)
A
- spermatogenesis: 4 equally - sized sperm cells are produced.
- oogensis: 1 large egg cell and 3 polar bodies are produced.
- fertilization: sperm (23 chromosomes) + egg (23 chromosomes) = zygote (46 chromosomes).
5
Q
What is prophase 1? (Meiosis)
A
- nuclear membrane dissolves, centrioles migrate to opposite ends, and spindle fibres form
- homologous chromosomes pair up in a process called synapsis to form a “tetrad” structure
- homologous exchange a section of DNA in a process called crossing - over as this creates genetic variation*
6
Q
What is metaphase 1? (Meiosis)
A
- spindle fibres attach onto homologous
- homologous chromosomes line up randomly in the middle to form the metaphase plate as this creates genetic variation *
- thus is called independent assortment
7
Q
What is anaphase 1? (Meiosis)
A
- spindle fibres pull apart the homologous chromosomes
- chromosomes move to opposite ends of the cell
8
Q
What is telophase 1 / cytokinesis (meiosis)
A
- nuclear membrane begins to reform
- spindle fibres disappear
- cytokinesis cause cell division
- END RESULT: 2 haploid daughter cells that are genetically different from the parent cell are produced
9
Q
What is prophase 2 (meiosis)
A
- nuclear membrane dissolves and spindle fibres form
10
Q
What is metaphase 2 (meiosis)
A
- spindle fibres attach onto chromosomes
- chromosomes line up in the middle to form the metaphase plate
11
Q
What is anaphase 2 (meiosis)
A
- spindle fibres pull apart the chromosomes
- sister chromatids move to opposite ends of the cell
- *similar to mitosis but half # of chromosomes
12
Q
What is telophase 2 (meiosis)
A
- nuclear membrane begins to reform
- spindle fibres disappear
- cytokinesis causes cell division
- END RESULT: in total, 4 haploid daughter cells (containing 23 chromosomes) that are genetically different from the parent cell are produced
13
Q
What is diploid? (Meiosis)
A
- cell that has 2 sets of chromosomes (46 in total)
14
Q
What is haploid? (Meiosis)
A
- cell that has 1 set of chromosomes (23 in total)
