Meiosis And Mitosis

Question 1

What is meiosis?

Answer 1

Type of cell division for sexual reproduction.
Producing haploid cells from a diploid cell.
Involves in two connective cell divisions ( meiosis 1 and meiosis 2) - same sequence of stages in both divisions.

Question 2

What is a reduction division?

Answer 2

Meiosis

Question 3

What is mitosis?

Answer 3

A type of cell division - asexual reproduction.

Question 4

What are the functions of mitosis?

Answer 4

Growth and tissue repair of multicellular organisms
Asexual reproduction in unicellular organisms

Question 5

What are the functions of meiosis ?

Answer 5

1. Reduces the number of chromosomes in the cell
2. Help increasing genetic variation

Question 6

What are gametes?

Answer 6

Special sex cells for sexual reproduction
# eggs in women
# sperm in men

Question 7

What is fertilization?

Answer 7

A process where the nuclei of two gametes fuse.

Question 8

What is a zygote?

Answer 8

The cell produced by fertilization.

Question 9

What is an haploid cell?

Answer 9

A cell that contain n chromosomes
# in humans 23

Question 10

What is a Parent cell?

Answer 10

The cell which performs the division.

Question 11

What are daughter cells?

Answer 11

The cells produced in the division

Question 12

How many daughter cells are produced in mitosis ?

Answer 12

2 (identical)

Question 13

How many daughter cells are produced in meiosis?

Answer 13

4 (non-identical)

Question 14

What are the stages in each division?

Answer 14

1. prophase
2. Metaphase
3. Anaphase
4. Telaphese

Question 15

What happens in Prophase 1?

Answer 15

• Chromosomes condense and become observable.
• chromosomes arrange themselves in homologous pairs (bivalent).
• nuclear envelope breaks down
• nacleous “disapears”
• centrioles migrate to opposite ends of the cell and form spindle fibers made from microtubules.
  # crossing over of chromatids may occur.

Question 16

What happens in metaphase 1?

Answer 16

• Homologous chromosomes pairs are lined up in the middle of the cell
• each homologous chromosome begins to pull to opposite poles.

Question 17

What happens in anaphase 1?

Answer 17

• The homologous chromosomes pulled to opposite poles of the cell
• the centromeres stay intact and hold the sister chromatid together.

Question 18

What happens in telophase 1?

Answer 18

Nuclear envelope forms around each set o chromosomes and the nucleus generally reforms.
2 cells created

Question 19

What happens in prophase 2?

Answer 19

Nuclear envelope and nucleus break

Question 20

What happens in metaphase 2?

Answer 20

The chromosomes line up at the equator of the spindle

Question 21

What happens in anaphase 2?

Answer 21

Centromers divide and sister chromatids are pulled in opposite poles of the cell

Question 22

What happens in telophase 2?

Answer 22

Nuclear envelope and nucleus reform.

Question 23

What happens in telophase 2?

Answer 23

Nuclear envelope and nucleus reform.

Question 24

What happens during cytokinesis?

Answer 24

Cytoplasm splits in 2, forming two whole cells.
Either 2 identical diploid cells ( mitosis ) or twice 2 non-identical haploid cells

Question 25

How many chromosomes and chromatids in prophase of mitosis ?

Answer 25

Chromosomes: 46 chromatids: 92

Question 26

How many chromosomes and chromatids in metaphase of mitosis ?

Answer 26

Chromosomes: 46 Chromatids: 92

Question 27

How many chromosomes and chromatids in anaphase of mitosis ?

Answer 27

Chromosomes: 92 Chromatids :92

Question 28

How many chromosomes and chromatids in telophase of mitosis ?

Answer 28

Chromosomes: 92 Chromatids: 92

Question 29

How many chromosomes and chromatids in prophase 1 of meiosis ?

Answer 29

Chromosomes: 46 Chromatids: 92

Question 30

How many chromosomes and chromatids in metaphase 1 of meiosis ?

Answer 30

Chromosomes: 46 Chromatids: 92

Question 31

How many chromosomes and chromatids in anaphase 1 of meiosis ?

Answer 31

Chromosomes: 46 Chromatids: 92

Question 32

How many chromosomes and chromatids in telophase 1 of meiosis ?

Answer 32

Chromosomes: 46 Chromatids: 92

Question 33

How many chromosomes and chromatids are in the end of meiosis 1 ?

Answer 33

Chromosomes: 23 Chromatids: 46

Question 34

How many chromosomes and chromatids are in prophase 2 of meiosis ?

Answer 34

Chromosomes: 23 Chromatids: 46

Question 35

How many chromosomes and chromatids are in metaphase 2 of meiosis ?

Answer 35

Chromosomes: 23 Chromatids: 46

Question 36

How many chromosomes and chromatids are in anaphase 2 of meiosis ?

Answer 36

Chromosome: 46 Chromatids: 46

Question 37

How many chromosomes and chromatids are in telophase 2 of meiosis ?

Answer 37

Chromosomes: 46 Chromatids: 46

Question 38

What is a locus?

Answer 38

The position of a gene on a chromosome.

Question 39

What is the detention of genetic variation?

Answer 39

For the same trait there is more that one phenotype.

Question 40

What are the major sources of genetic variation?

Answer 40

1. Crossing over 2. Independent assortment ( random segregation) 3. Random fertilization.

Question 41

When does crossing over occur?

Answer 41

# May start at prophase 1 of meiosis

Question 42

What happens during the crossing over process?

Answer 42

Information is transferred between non-sister chromatids. homologous pair associate loosely along their length ( synapsis). DNA portions of non-sister chromatids are broken by specific proteins at precisely matching positions ( the specific corresponding location contain the same genes ( may contain different alleles ).

Question 43

When is the independent assortment process occurs?

Answer 43

Before metaphase 1 in meiosis

Question 44

How does random segregation cause variation?

Answer 44

Random orientation of bivalents result in many different combinations of chromosomes and therefore many deterrent combinations of alleles.

Question 45

How does random fertilization cause variation?

Answer 45

Any male gamete can fuse with any female gamete0 The fertilization is random.