Cell DIvision

Question 1

A cell has what three possible destinys

Answer 1

• live and function without dividing
• grow and divid
• die

Question 2

What is the cell theory

Answer 2

States that all organisms are made of cells and all cells come from pre-existing cells

Question 3

In somatic cell division, how do cells divide

Answer 3

Mitosis: diploid (2n) to diploid (2n)

Question 4

In reproductive cell division, how do cells divide

Answer 4

Through meiosis - diploid (2n) to haploid (1n)

Question 5

Why do somatic cells divide

Answer 5

• growth and development
• tissue renewal

Question 6

in regards to cells

What do somatic cells result in

Answer 6

2 daughter cells that are genetically and functionally identical to the parent cell

Question 7

Do all somatic cells divide

Answer 7

Many, but not all, some more than others

Question 8

What are somatic cells doing most of the time?

Answer 8

Going about their functions, within interphase

Question 9

What is happening in the G1: Growth or Gap phase 1 (interphase)

Answer 9

Most cellular activities are occuring here.

Question 10

What is happening in the S: Synthesis of DNA phase (interphase)

Answer 10

DNA replication occurs where strands are separated at the H bonds holding the nucleotides together.
New strand of DNA is synthesied opposite each of the old strands.

Question 11

What is happening in the G2: Growth or Gap Phase 2 (interphase)

Answer 11

Checks for correct DNA synthesis as it preapres for the mitotic phase (synthesis of the proteins and enzymes are required, gathering of reactants).
Replication of centrosomes is completed.

Question 12

What are the three phases involved in Interphase of the eukaryotic cell cycle

Answer 12

G1 (growth or gap phase 1), S (syntheis of DNA), G2 (growth or gap phase 2)

Question 13

How long does the G1 phase take

Answer 13

8-10 hours

Question 14

How long does the G2 phase take

Answer 14

4-6 hours

Question 15

How long does the S phase take

Answer 15

8 hours

Question 16

What are the 4 parts of the mitotic phase

Answer 16

1. prophase
2. metaphase
3. anaphase
4. telophase and cytokinesis

Question 17

in terms of chromosomes

What does a human diploid have

Answer 17

46 chromosomes, 23 from each parent

Question 18

During interphase, DNA ___

Answer 18

Replicates

Question 19

During prophase, DNA __

Answer 19

Condenses
and there are two identical chromatids per chromosome called sister chromatids

Question 20

What are sister chromatid

Answer 20

Two identical chromatids per chromosome

Question 21

During metaphase, chromosomes __

Answer 21

“line up”

Question 22

What happens during anaphase

Answer 22

Sister chromatids separate before the nuclear envelope reforms in the telophase

Question 23

Daughter cells are __ to the parent cell

Answer 23

Identical

Question 24

What does the cell cycle result as an end product

Answer 24

Two daughter cells that are genetically identically to the parent cell

Question 25

What do the G1 checkpoints in the cell cycle check fore

Answer 25

* Is the DNA undamaged * is cell size and nutrition okay * are appropriate cell signals present

Question 26

What happens if the G1 checkpoint is not satisfied

Answer 26

Exit to G0

Question 27

What do the M checkpoints check for

Answer 27

* Are all chromosomes attatched to spindles

Question 28

What happens when there is without full chromosome attatchment during the M signal

Answer 28

Stop signal received

Question 29

Where does meiosis occur

Answer 29

Occurs in the gonads (ovaries and testes

Question 30

What is the purpose of meiosis

Answer 30

* produces gametes which are haploid (single set of 23 chromosomes) * fertilisation then restores the diploid number of chromosomes (2n) * produces cells that are genetically different from the parent cell

Question 31

How many stages of meiosis are there

Answer 31

2

Question 32

What is Meiosis 1

Answer 32

Separates homologous chromosomes

Question 33

What happens in Prophase 1

Answer 33

Synapsis: when two sister chromatids of each pair of homologous chromosomes pair up. The four chromatids are called a tetrad

Question 34

What happens in Metaphase 1

Question 35

What happens in Anaphase 1

Answer 35

Sister chromatids remain attatched and homologous chromosomes separate

Question 36

What happens in Telophase 1 and Cytokinesis

Answer 36

Cleavage furrow

Question 37

How is Meiosis ll different to Meiosis l

Answer 37

Very similar but meiosis ll is not preceded by DNA replication

Question 38

For mitosis, DNA replication occurs in ____ but in meiosis it occurs in ___.

Answer 38

1. both diploid and haploid cells 2. diploid cells only

Question 39

For DNA replication in mitosis, it occurs during ____ but for meiosis, it occurs during ______.

Answer 39

1. interphase before mitosis begins 2. interphase before meiosis l but not meiosis ll

Question 40

What is the number of divisions for mitosis compared to meiosis

Answer 40

For meiosis, there is 1 (including prophase, prometaphase, metaphase, anaphase and telophase) For mitosis, there is 2 (including prophase, metaphase, anaphase and telophase

Question 41

For the synapsis of homologous chromosomes, does it occur in meiosis and mitosis (and if so when)

Answer 41

Does not occur for mitosis For meiosis: occurs during prophase 1 along with crossing over between non-sister chromatids; resulting chiasmata holds pairs together due to sister chromatid cohesion

Question 42

What is the number of daughter cells and genetic composition in mitosis and meiosis

Answer 42

Mitosis: two Meiosis: Four

Question 43

For mitosis, what is the number of daughter cells and genetic composition

Answer 43

Two, each genetically identical to the parent cell, with the same number of chromosomes

Question 44

For meiosis, what is the number of daughter cells and genetic composition

Answer 44

Four, each haploid (n); genetically different from the parent cell and from each other

Question 45

# Three sources What are the sources of variation as a result of meiosis

Answer 45

* Independent assortment at metaphase 1 * crossing over at prophase 1 * Fusion between two gametes