Chapter 11 Cell Cycle, Mitosis

Question 1

In cell division, what does a single cell become?

Answer 1

Two daughter.

Question 2

What are the two requirements in cell division?

Answer 2

1. Two daughter cells must receieve the complete genome present in the single parent cell.
2. The parent cell must be large enough to divide in two and still contribute sufficient cytoplasmic components to each daughter cell.

Question 3

What are the 2 major types of chromosomes?

Answer 3

Autosomes and sex chromosomes. Humans have 22 pairs of autosomes, and the X and Y determine whether we are male or female.

Question 4

What does chromatin consist of?

Answer 4

DNA and protein.

Question 5

What is each DNA packaged with histone proteins into forming chromatins?

Answer 5

Nucleosomes.

Question 6

What are homologous chromosomes?

Answer 6

A pair of the same kind of chromosomes. Homologous chromosomes are similar in length, centromere positions and have the same gene.

Question 7

What is an allele?

Answer 7

Alleles are different version of a gene. Each allele resides on same location of one of the pairs of homologous chomosomes.

Question 8

What are the types of homozygous?

Answer 8

Homozygous for dominant allele (AA); homozygous for recessive (aa).

Question 9

What is heterozygous?

Answer 9

Aa; one dominant and one recessive alleles.

Question 10

What is a haploid cell?

Answer 10

A cell with 1 complete set of chromosomes.

Question 11

What is a diploid cell?

Answer 11

A cell with 2 complete sets of chromosomes.

Question 12

When do chromosomes replicate?

Answer 12

S phase.

Question 13

What is a sister chromatid and how do they form?

Answer 13

Sister chromatids are genetically identical and they are produced when the chromosomes are replicated during the S phase of the cell cycle.

Question 14

What is kinetochore? What are they attached by?

Answer 14

They are proteins and each kinetochore is associated with one of the two sister chromatids and forms the site of attachment for a single microtuble.

Question 15

What are the 2 phases of a cell cycle?

Answer 15

M phase and interphase.

Question 16

What does M phase consist of?

Answer 16

Mitosis and cytokinesis.

Question 17

What are the phases in mitosis?

Answer 17

Prophase, prometaphase, metaphase, anaphase, telephase.

Question 18

What happens in prophase?

Answer 18

Nucleoli disappears; mitosis spindle emerges centrosomes move to opposite pole; chromosomes are condensed with sister chromatids.

Question 19

What many chromosomes do humans have in a cell at prophase of mitosis?

Answer 19

46.

Question 20

How many chromatids do humans have in a cell at prophase of mitosis?

Answer 20

92 chromatids.

Question 21

What happens in prometaphase lf mitosis?

Answer 21

Nuclear envelope breaks down; miotoc spindles attach to chromosomes via kinetochore.

Question 22

What happens in metaphase of mitosis?

Answer 22

Chromosomes are moved to the mataohase plate; kinetochore of sister chromatids face opposite poles.

Question 23

What happens in anaphase of mitosis?

Answer 23

Sister chromatids separate (become chromosomes) and moced to the opposite poles by microtubules; elongate the cell; result: two ends of the cell have equal and complete sets of chromosomes.

Question 24

How many chromosomes do we have in a cell at anaphase of mitosis?

Answer 24

92 chromosomes.

Question 25

How many chromatids do we have in anaphase of mitosis?

Answer 25

0.

Question 26

What happens in telephase of mitosis?

Answer 26

Miotic spindle disappears; nuclear envelope refomed; 2 nuclei created; chromosomes decondensed and less visible.

Question 27

What are th ephases in interphase?

Answer 27

G1, Go, S, G2.

Question 28

What happens in Go phase?

Answer 28

Resting phase, no active preparation activity, some cells remain in Go phase permanently.

Question 29

What happens in G1 phase?

Answer 29

Cell size and protein content increases; cell prepares for DNA synthesis.

Question 30

What happenes in S phase?

Answer 30

DNA synthesis; chromosomes replicate.

Question 31

What happens in G2 phase?

Answer 31

2 centrosomes emerge; nucleus visible; chromatin not condensed, still invisible chromatin.

Question 32

What are the roles of mitosis?

Answer 32

Reproduce aesexually for single cell; growth for multicellular organisms ( e.g. Fertilized egg to adult); repair for maintanance of actively dividing tissues e.g. Skin.

Question 33

What happens in cytokinesis?

Answer 33

As mitosis ends, cytokinesis begins and the parent cell’s cytoplasm divides into two daught cells.