Topic 1 Reproduction,1.1,Mitosis&Meiosis

Question 1

What is the purpose of mitosis in the process of gametogenesis?

Answer 1

To expand the PGC population

Question 2

What comes before mitosis and meiosis?

Answer 2

interphase:
G1 (normal growth), S (DNA rep), G2 (increased growth)
this is a CYCLE

Question 2

What is the purpose of meiosis in the process of gametogenesis?

Answer 2

To actually make germ cells into either haploid egg or sperm
*SEXUAL REPRODUCTION

Question 2

T/F: The chromosomal number is somatic cells during mitosis are halved

Answer 2

No

Question 3

___is the process by which the number of chromosomes in a cell
nucleus is halved during the formation of germ cells (eggs and sperm).

Answer 3

Meiosis

Question 4

“One way process” is used to describe mitosis or meiosis?

Answer 4

meiosis

Question 5

How many chromosomes does everyone have in every body cell?

Answer 5

46, 23 form mom, 23 from dad

Question 6

What are the stages of mitosis?

Answer 6

prophase,prometaphase,metaphase,anaphase,telophase,cytokinesis

Question 7

Explain stage of prophase(mitosis)

Answer 7

During S phase of interphase, our DNA has already duplicated so now we have 46 sister chromatids. Prophase early mitotic spindles start to from between centromeres that are pushing apart

Question 8

Explain stage of prometaphase(mitosis)

Answer 8

Fragments of nuclear envelopes+ kinetochore microtubules

Question 9

In anaphase, how many chromosomes are there?

Answer 9

46

Question 9

What happens during metaphase(mitosis)?

Answer 9

Sister chromatids start to align along metaphase plate

Question 10

Goal of meiosis I is to ___

Answer 10

separate homologous chromosomes

Question 11

How many homologous chromosomes are there during meiosis I

Answer 11

23

Question 12

Before prophase of meiosis I: how many chromosomes

Answer 12

Still 46, 23 form mom an 23 from dad, however, the DNA has replicated so each chromosome is a sister chromatid.

Question 13

Explain prophase meiosis I

Answer 13

23 homologous chromosomes/tetrads linked by chiasmata, centromeres separate to opposite poles and spindles form

Question 14

Explain Metaphase Meiosis I

Answer 14

Linking of homologous chromosomes along the metaphase plate, microtubules attach to kinetochore

Question 15

Explain Anaphase meiosis 1

Answer 15

Homologous chromosomes separate, however, sister chromatids remain attached

Question 16

T/F: At end of Meiosis 1 there are 2 haploid cells

Answer 16

True

Question 17

What is the result of Meiosis II?

Answer 17

4 haploid cells

Question 18

When does DNA replication occur during mitosis and meiosis?

Answer 18

During interphase, before mitosis and meiosis begins

Question 19

T/F there are 2 division in mitosis

Answer 19

False: 1 division in mitosis and 2 divisions in meiosis

Question 20

T/F Synapsis of homologous chromosomes occurs during meiosis

Answer 20

Yes, it is the crossing over betweeen nonsister chromatids during prophase 1.

Question 21

A tetrad is

Answer 21

group of 4 chromatids

Question 22

How are the daughter cells different between mitosis and meiosis?

Answer 22

Mitosis: 2 daughter cell are diploid (2n), genetically identical to parent Meiosis: 4 daughter cells that are haploid(23), has half as may chromosomes of parents and are non genetically identical

Question 22

What is the role of mitosis in the animal body?

Answer 22

Allows zygote to become a multicellular body, produces cells for jobs like tissue repair

Question 23

What is the role of meiosis in the animal body?

Answer 23

Produce gametes which are haploid meaning they contain a number of chromosomes and also are genetically variable

Question 24

Why is it favorable to have offspring of varying genotypes?

Answer 24

1. one genotype may better enhance reproductive success than another under changing environmental factors 2. may enhance adaptive genes, lose unfavorable genes

Question 25

Name the two ways to generate variation within meiosis.

Answer 25

1. Chromosome segregation (Independent Assortment) 2. Crossing over (homologous recombination)

Question 26

What is the formula used to calculate independent assortment in cells undergoing meiosis I?

Answer 26

number of possible orientations= 2^n n= number of chromosome pairs 2=number of chromosomes in each pair

Question 27

Crossing over occurs at what step?

Answer 27

Prophase of meiosis I

Question 28

In a cell with 4 chromosomes, how many sister chromatids are visible at the end of telophase/cytokinesis?

Answer 28

0

Question 29

How much genetic material is present in a cell during anaphase I compared to a cell during metaphase?

Answer 29

the same amount

Question 30

Embryonic cells undergo ____, making more diploid cells

Answer 30

mitosis