Chapter 12: Mitosis

Question 1

Purpose of cell division in unicellular vs multicellular organisms

Answer 1

-Unicellular organisms divide to replicate themselves into offspring

-Multicellular organisms divide cells for Growth, Development, and Repair.

Question 2

Genome

Answer 2

All of the DNA in a cell. Can be a single DNA molecule, especially in prokaryotic cells. Can also be a number of DNA molecules, especially in eukaryotic cells.

Question 3

Chromosome

Answer 3

A DNA molecule wound around histones into a very compact shape.

Can be just one chromatid or two sister chromatids (the latter forms the iconic “x” shape)

Question 4

Somatic Cell

Answer 4

Nonreproductive, has two sets of chromosomes (“diploid”).

Question 5

Gamete

Answer 5

Reproductive haploid cells. DONT have homologous pairs.

Question 6

Chromatin

Answer 6

A complex of DNA and protein that condenses during cell division. Chromosomes are made of this.

Question 7

Sister chromatids

Answer 7

After the S phase, there is an identical copy of each DNA molecule. When they condense into chromatids in prophase they are considered sister chromatids.

Question 8

Eukaryotic cell division stages (two, not PMAT)

Answer 8

-Mitosis
-Cytokinesis (division of cytoplasm)

Question 9

Two major phases of the cell cycle?

Answer 9

-(M) Mitotic phase, includes mitosis AND cytokinesis
-Interphase, including cell growth and DNA replication

Question 10

Three phases of Interphase

Answer 10

G1 - “First Gap”
S - “Synthesis”
G2 - “Second Gap

Cell grows in all of these stages.

Question 11

Five phases of mitosis

Answer 11

Prophase
(Prometaphase)
Metaphase
Anaphase
Telophase

Question 12

Prophase

Answer 12

DNA molecules are condensed into Chromosomes
-Microtubules extend from the centrioles as the centrioles move to opposite ends of the cell

Question 13

Prometaphase

Answer 13

-Often considered part of prophase
-Nuclear membrane begins to break down
-Microtubules from centrioles attach to chromosomes

Question 14

Metaphase

Answer 14

-Chromosomes align along “metaphase plate”, imaginary line down the middle of the cell.

Question 15

Anaphase

Answer 15

-Microtubules pull sister chromatids apart from each other: one goes to one centriole, the other goes to the other

Question 16

Telophase

Answer 16

-Nuclear envelopes begin to form around the two collections of chromosomes
-Cell begins to split, cytokinesis generally begins here

Question 17

In humans-
How many chromosomes in prophase?
How many chromatids in prophase?

Answer 17

46
92

Question 18

Cytokinesis

Answer 18

Division of cytoplasm

Question 19

Centriole

Answer 19

Structure made of microtubules, from which microtubules extend to bind to chromosomes during prometaphase.