Cell Division

Question 1

What is a somatic cell and how many chromosomes do they have?

Answer 1

-Diploid human body cell
-46 chromosomes (2 sets of 23 from each parent)

Question 2

What are gametes and how many chromosomes do they have?

Answer 2

-Haploid reproductive cells produced in meiosis
-23 chromosomes

Question 3

What process do prokaryotes undergo to reproduce?

Answer 3

Reproduce asexually to create the entire organism through mitosis

Question 4

What process do eukaryotes undergo to reproduce?

Answer 4

Cell division for…
-Meiosis: development from a fertilized egg
-Mitosis: growth and repair

Question 5

Stages of Mitosis and Cytokinesis

Answer 5

1. prophase
2. prometaphase
3. metaphase
4. anaphase
5. telophase
6. cytokinesis

Question 6

Prophase

Answer 6

(6 chromosomes) 2n
Chromosomes start to condense into your familiar duplicated chromosome image. Spindle starts to form.

Question 7

Prometaphase

Answer 7

(6 chromosomes) 2n
Spindle has formed across cell and chromosomes are attaching to kinetochore microtubules. Nuclear membrane gone.

Question 8

Metaphase

Answer 8

(6 chromosomes) 2n
Fully condensed and duplicated chromosomes align in center. (not homologous pairs)

Question 9

Anaphase

Answer 9

(12 chromosomes)
Sister chromatids split apart to opposite poles.

Question 10

Telophase

Answer 10

(12 chromsomes)
2 nuclei and NM reform around each.

Question 11

Cytokinesis

Answer 11

(6 chromosomes) 2n
Cytoplasm separate to create two diploid daughter cells.

Question 12

Difference between cytokinesis in animal and plant cells

Answer 12

Cytokinesis in animal: There is a furrow at the center that pinches the cells in 2 like constricting a soft water balloon.

Cytokinesis in plants: They have a cell wall so they split down the middle and create new cell wall down the middle.

Question 13

What is the importance of mitosis?

Answer 13

Doubling and separating allows the preservation of the chromosomes number during mitosis.

Question 14

Stages of Meiosis

Answer 14

Meiosis 1: homologous chromosomes separate –> haploid cells w duplicated chromosomes

Meiosis 2: sister chromatids separate –> haploid cells w unduplicated chromosomes

Question 15

Prophase 1

Answer 15

(6 chromosomes) 2n
Homologous chromosomes pair and non-sister chromatids recombine in crossing over

Question 16

Metaphase 1

Answer 16

(6 chromosomes) 2n
Each homolog pair lines up at metaphase independently (independent assortment)

Question 17

Anaphase 1

Answer 17

(6 chromosomes) 2n
Homologs are separated to opposite poles

Question 18

Telophase 1 & Cytokinesis

Answer 18

(Telo = 6 2n, Cyto = 3 n)
Two different haploid cells form, they are not identical as in mitosis

Question 19

Prophase 2

Answer 19

begin w 2 diff haploid cells (each n)
Spindle apparatus forms

Question 20

Metaphase 2

Answer 20

each n
Chromosomes position to metaphase plate

Question 21

Anaphase 2

Answer 21

2n
chromatids separate

Question 22

Telophase 2 and Cytokinesis

Answer 22

creates 4 genetically distinct daughter cells (n)

Question 23

Function of mitosis

Answer 23

to make identical body cells

Question 24

Function of meiosis

Answer 24

to make viable gametes

Question 25

Sources of genetic variation-sexual reproduction (does not occur during mitosis)

Answer 25

1. independent assortment (metaphase 1 of meiosis-homologs) 2. crossing over/recombination between non-sister chromatids (prophase 1 of meiosis-homologs) 3. Random fertilization (occurs after meiosis when parent gametes fuse) 4. mutations

Question 26

Fertilization

Answer 26

combines two haploid cells (sperm & egg) back to diploid state (zygote)

Question 27

How does asexual reproduction gain genetic variety?

Answer 27

Mutations

Question 28

Is self-fertilization asexual or sexual?

Answer 28

Some organisms are hermaphroditic, meaning they contain both male and female gametes. Those organisms are able to self-fertilize. Despite the fact that these gametes come from the same individual, we still consider this *sexual reproduction*, as two gametes are involved.