Meiosis (5)

Question 1

Gametes

Answer 1

• reproductive cells (sperm/eggs)
• haploid cells with a single set of chromosomes

Question 2

Somatic cells

Answer 2

Any cells that aren’t gametes

Question 3

Karyotype

Answer 3

Ordered display of all chromosome pairs in a cell

Question 4

Homologous chormosomes/homologs

Answer 4

2 chromosomes in a pair

Question 5

Autosomes

Answer 5

Any pair of chromosomes that aren’t sex chromosomes

Question 6

Diploid cell

Answer 6

Has two sets of chromosomes

Question 7

Haploid cell

Answer 7

Has a single set of chromosomes

Question 8

Zygote

Answer 8

• Fertilized egg
• Has one set of chromosomes from each parent

Question 9

What are the stages of Meiosis

Answer 9

• Interphase
• Meiosis 1
• Cytokinesis
• Meiosis 2
• Cytokinesis

Question 10

What are the stages in Meiosis 1

Answer 10

Prophase 1 - chromosomes pair with their homologs, at x shaped regions crossing over occurs
Metaphase 1 - pairs of homologs line up at the metaphase plate
Anaphase 1 - pairs of chromosomes are pulled apart to opposite sides of the cell
Telophase 1 - each cell has a haploid set of duplicated chromosomes

Question 11

What are the stages of Meiosis 2

Answer 11

Prophase 2 - spindle forms
Metaphase 2 - chromosomes line up at the metaphase plate
Anaphase 2 - chromosomes are split into their two sister chromatids and pulled to opposite sides of the cell
Telophase 2 - chromosomes decondense and the nuclear envelop reforms

Question 12

How are meiosis and mitosis similar

Answer 12

• nuclear envelope disappears
• DNA coils into chromosomes
• chromosomes align in the center of the cell
• fibers separate chromosomes
• nuclear envelope reappears
• chromosomes uncoil
• followed by cytokinesis and the production of daughter cells

Question 13

How are mitosis and meiosis different

Answer 13

Mitosis:
- creates 2 daughter cells
- creates cells that are genetically identical to each other and the parent cell
- conserves the number of chromosome sets
- sister chromatid cohesions are cleaved at the end of metaphase

Meiosis:
- creates 4 daughter cells
- creates cells that are genetically varied
- reduces the number of chromosome sets from 2 diploid to 1 haploid
- cohesions between homologs are cleaved in anaphase 1 and between sister chromatids in anaphase 2
- has synapsis/crossing over in prophase 1
- during metaphase 1 homologous pairs align at the metaphase plate
- during anaphase 1 homologs are separated

Question 14

What are the three ways mieosis creates genetic variation

Answer 14

• Independent assortment of chromosomes
• crossing over
• random fertilization

Question 15

How does independent assortment of chromosomes contribute to genetic variation

Answer 15

• homologous pairs of chromosomes are oriented randomly in metaphase 1 so they are sorted independently of other pairs
• # of possible combinations with independent assortment = 2^n (n=haploid number)

Question 16

How does crossing over contribute to genetic variation

Answer 16

Produces recombinant chromosomes which combines DNA inherited from both parents

Question 17

How does random fertilization contribute to genetic variation

Answer 17

• Any sperm can fuse with any egg
• Crossing over within the gametes creates a lot of variation