Chapter 3

Question 1

What are the types of cell division?

Answer 1

2 types, mitosis and meiosis

Question 2

Mitosis :

It produces :

Answer 2

The growth and repair of body cells

-2 genetically identical daughter cells w/ the same chromosome number as the parent cell

Question 3

(mitosis) Each daughter cell is

Answer 3

Diploid (2n), just like its parent cell

Question 4

Meiosis

Each resulting cell:

Answer 4

1. Occurs on in sexually reproducing organisms
2. it produces gametes (sperm and ova) w/ ½ the chromosome number of the parent cell
3. Is haploid (n)

Question 5

Chromosome consists of

Answer 5

A highly coiled and condensed strand of DNA

Question 6

A replicated chromosome consists of

Answer 6

2 sister chromatids, where 1 is an exact copy of the other

Question 7

Centromere

Answer 7

A specialized region that holds the 2 sister chromatids together

Question 8

Spindle fibers connect the

Answer 8

Centromere to the centrosome during cell division

Question 9

Each chromosome contains

Answer 9

2 identical chromatids connected at a centromere

Question 10

Cell cycle

Answer 10

When living and dividing cells pass through a regular sequence of growth and division

Question 11

Stem cells (from human embryos)

Answer 11

1. Retain the ability to divide indefinitely

2. to differentiate into any cell type

Question 12

Cell cycle is strictly regulated by many

Answer 12

Proteins including some called cyclins

Question 13

Some proteins are internal regulators making sure

Answer 13

That the cell does not undergo mitosis until certain conditions are met

Question 14

Other proteins such as growth factors are

Answer 14

External regulators of the cell cyle: speeding up, slowing it down, or even stopping it

Question 15

Cell cycle consists of

To move from one phase to the next

Answer 15

5 stages: G1 , S, G2, mitosis, cytokinesis

The cell must pass through 3 checkpoints

Question 16

G1

Answer 16

Newly divided cell enters this phase right after completing mitosis

Question 17

During G1, the cell

Answer 17

1. Increases in size

2. prepares to replicate it’s DNA

Question 18

G-1 checkpoint

Answer 18

If the cell is:
- healthy 
- contains adequate resources 
- DNA is undamaged,
 growth factors stimulate the cell to proceed to DNA synthesis of S phase

Question 19

If the cell doesn’t pass G1-checkpoint, the cell

Answer 19

Dies or enters a resting state, G0 phase

Question 20

S-phase

Answer 20

DNA is synthesized through the process of replication

Question 21

S-checkpoint

Answer 21

DNA synthesis is monitored for any replication errors

Question 22

S-phase checkpoint: If the synthesis progresses without errors

Answer 22

Growth signals will stimulate the cell to proceed to G2

Question 23

G-2

Answer 23

Cell has to produce organelles and other cellular components that will populate two new functional daughter cells

Question 24

G-2 checkpoint

Answer 24

All chromosomes must be
1. fully replicated
2.contain no other types of damage
only then can the cell enter M phase

Question 25

When errors occur in cell division, it causes the

Answer 25

Development of cancer

Question 26

More than ____% of life of a cell is spent in _______.

Answer 26

90%, interphase

Question 27

Most cells observed under a microscope are

Answer 27

In interphase

Question 28

During interphase, chromosomes

Answer 28

Replicate in preparation for cell division

Question 29

During interphase, 1 or more nucleoli become visible within the nucleus and

Answer 29

The nuclear membrane remains intact

Question 30

Interphase is made up of

Answer 30

G1, S, G2

Question 31

Mitosis is

Answer 31

Actual division of the nucleus

Question 32

Mitosis is divided into 4 phases

Answer 32

Prophase, metaphase, anaphase, and telophase

Question 33

Prophase

Answer 33

1. Strands of chromosomes begin to condense and become visible 2. Nucleoli disappear 3. Spindle fibers begin to form in the cytoplasm extending from 1 centrosome to the other 4. centrioles begin to migrate to the poles, 5. nuclear membrane begins to disintegrate

Question 34

Metaphase

Answer 34

1. Chromosomes line up single file located on the equator or (metaphase plate) 2. centrosomes are at opposite poles of the cell 3. spindle fibers run from centrosomes to the centromeres of the chromosomes

Question 35

Anaphase

Answer 35

1. Centromeres of each chromosome separate and spindle fibers begin to pull the sister chromosomes apart 2. anaphase is the shortest phase of mitosis

Question 36

Telophase

Answer 36

1. Chromosomes cluster at opposite ends of the cell and the nuclear membrane reforms 2. supercoiled chromosomes begin to unravel and tor return to their pre-cell division condition as long , threadlike strands 3. the nuclear membrane reforms

Question 37

Cytokinesis

Answer 37

Division of the cytoplasm

Question 38

In animal cells, a cleavage furrow forms

Answer 38

Down the middle of the cell as the cytoplasm pinches inward and the 2 daughter cells separate from each other

Question 39

In plant cells, a cell plate forms down

Answer 39

The middle of the cell

Question 40

Daughter cells do not

Answer 40

Separate from each other ,instead a sticky middle lamella cement adjacent cells together

Question 41

Meiosis

Answer 41

A form of cell division in which cells having the diploid chromosome number (2n) produce gametes (sex cells) with the haploid chromosome number (n)

Question 42

Meiosis occurs in

Answer 42

2 stages, meiosis I and meiosis II

Question 43

Meiosis I is also called

Answer 43

Reduction division

Question 44

What occurs in meiosis I?

Answer 44

Synapsis and crossing-over

Question 45

Synapsis

Answer 45

Chromosomes pair up precisely w/ their homologue so that crossing-over can occur

Question 46

Crossing-over

Answer 46

The process in which homologous chromatids exchange genetic material, it ensures greater variety in the gametes

Question 47

Homologous chromosomes separate, failure to separate is

Answer 47

Nondisjunction

Question 48

Next, chromosomes line up randomly on the

Answer 48

Equatorial plate and separate independently

Question 49

This means that how 1 pair of chromosomes lines up and separates

Answer 49

Has no effect on how any other pair of chromosomes lines up and separates

Question 50

Each resulting gamete is

Answer 50

Genetically unique

Question 51

Meiosis II

Answer 51

Sister chromatids separate

Question 52

This division

Answer 52

Maintains the haploid number of chromosomes

Question 53

This phase completes the goal of meiosis

Answer 53

Producing 4 genetically unique cells from 1 original mother cell

Question 54

In metaphase I of meiosis I | In metaphase II of meiosis II

Answer 54

Chromosomes are lined up double files | Chromosomes are lined up single files

Question 55

Summary:

Answer 55

Mitosis is for growth/repair and meiosis is for the production of gametes only

Question 56

Summary of meiosis I and II

Answer 56

I: homologous pairs separate II: sister chromatids separate