Cellular Division and the Cell Cycle - Ch. 8

Question 1

What happens during anaphase in mitosis?

Answer 1

Sister chromatids separate and move towards opposite poles of the cell. Each is now considered a full-fledged daughter chromosome.

Question 2

What are the three stages in interphase?

Answer 2

1. G1- 1st gap sequence growth; carrying out “cellular duties” 2. S Phase- chromosome duplication; DNA in nucleus is doubled 3. G2- 2nd gap sequence. Preparing for mitosis. Each chromosome in the cell consists of two identical sister chromatids.

Question 3

Are gametes haploid or diploid cells?

Answer 3

Haploid (n). They have only 1 set of chromosomes.

Question 3

homologous pair

Answer 3

matching pair of chromosomes that carries the same sequence of genes controlling the same inherited characteristics

Question 4

During which phase of meiosis does “crossing over” occur?

Answer 4

Prophase I

Question 5

What phase is this?

Answer 5

Meiosis- Telophase I

Question 6

What happens during metaphase in mitosis?

Answer 6

Chromosomes line up single-file along the metaphase plate

Question 6

What phase is this?

Answer 6

Mitosis - Anaphase

Question 7

What phase is this?

Answer 7

Meiosis- Telophase II

Question 8

What are the four main stages of mitosis?

Answer 8

1. Prophase 2. Metaphase 3. Anaphase 4. Telophase

Question 9

tetrad

Answer 9

Occurs during Prophase I of meiosis; homologous pairs stick together forming a tetrad

Question 11

What are chromosomes made up of?

Answer 11

Chromatin (DNA and proteins)

Question 12

What phase is this?

Answer 12

Meiosis- Prophase II

Question 13

How many copies of DNA does each chromosome contain at the beginning of mitosis?

Answer 13

TWO copies. This is because of replication.

Question 14

gene

Answer 14

specific region of DNA that codes for a specific trait

Question 15

The first part of the cell cycle (where the cell spends 90% of its time) is called ______

Answer 15

interphase, which is the period of cell growth; the cell makes new molecules and organelles.

Question 15

What phase is this?

Answer 15

Mitosis - Telophase

Question 15

What phase is this?

Answer 15

Meiosis- Metaphase II

Question 17

What happens during telophase in mitosis?

Answer 17

1. Nuclear envelope begins to reform 2. Centrosomes disappear 3. Spindle fibers disappear 4. Nucleoli reform 5. Chromosomes decondense back into chromatin

Question 17

What phase is this?

Answer 17

Meiosis- Anaphase II

Question 19

autosomes

Answer 19

the pairs of chromosomes that are the same in males and females. In humans, chromosomes #1 - #22

Question 20

sister chromatids

Answer 20

chromsome consisting of two copies

Question 21

What does mitosis produce?

Answer 21

2 identical diploid (2 sets of chromosomes) daughter cells. There is NO change in chromosome number. Chromosomes are in unduplicated form.

Question 22

What phase is this?

Answer 22

Meiosis: Anaphase I

Question 23

What phase is this?

Answer 23

Meiosis- Metaphase I

Question 25

What does meiosis produce?

Answer 25

4 haploid daughter cells containing half the number of chromosomes as the parental nucleus.

Question 26

During which phase of meiosis does “independent assortment” occur?

Answer 26

Metaphase I

Question 27

What’s the haploid number for humans?

Answer 27

23

Question 28

sex chromosomes

Answer 28

In humans, it is chromosome #23. Females = XX Males = XY

Question 29

meiosis

Answer 29

formation of gametes (reproductive cells, e.g. eggs and sperm, ovules and pollen)

Question 30

centromere

Answer 30

the narrow “waist” that sister chromatids are joined together at

Question 31

What happens during prophase in mitosis?

Answer 31

1. Nuclear envelope disappears 2. Chromatin condenses to form chromosomes, each consisting of two sister chromatids 3. Mitotic spindle forms 4. Centrosomes move towards opposite poles 5. Nucleoli disappear

Question 33

What happens during cytokinesis in mitosis?

Answer 33

Cytokinesis usually occurs with telophase. It is the division of the cytoplasm. In animals, a cleavage furrow pinches the cell in two, producing two daughter cells. In plants, vesicles move to middle of cell and produce a cell plate, and a new cell wall is created.

Question 34

asexual reproduction

Answer 34

one individual produces offspring and those offspring directly inherit the genes of the parent

Question 35

Why do cells go through mitosis?

Answer 35

Reproduction (asexual) Growth and development Repair and regeneration

Question 36

What is mitosis?

Answer 36

The division of a cell, resulting in daughter cells that are genetically identical to the parent cell.

Question 37

What phase is this?

Answer 37

Meiosis- Prophase I

Question 38

What phase is this?

Answer 38

Mitosis- Metaphase

Question 39

What occurs during the S Phase in Interphase?

Answer 39

All of the chromosomes are replicated. Following replication, each chromosome now consists of two sister chromatids. Once DNA replication is complete the cell contains twice its normal number of chromosomes and becomes ready to enter the phase called G2.

Question 40

Where are chromosomes located in eukaryotic cells?

Answer 40

Nucleus

Question 41

No question here. Just look at this picture of duplicated, unduplicated, and homologous chromosomes.

Question 42

In what stages of interphase, mitosis, and meiosis are chromosomes duplicated and unduplicated?

Answer 42

*Interphase: *

G1- Unduplicated

S Phase- Duplicated

G2- Duplicated

Mitosis:

Prophase- Duplicated

Metaphase- Duplicated

Anaphase- Unduplicated

Telophase- Unduplicated

Meiosis:

Prophase I: Duplicated

Metaphase I: Duplicated

Anaphase I: Duplicated

Telophase I: Duplicated

Prophase II: Duplicated

Metaphase II: Duplicated

Anaphase II: Unduplicated

Telophase II: Unduplicated

Question 43

Just look at the photo.

Answer 43

Yay!

Question 44

What’s a metaphase plate?

Answer 44

a plane in the equatorial region of the spindle in dividing cells, alongwhich the chromosomes become arranged during the metaphase

Question 45

What three processes contribute to an increase in genetic variation in sexually reproducing organisms?

Answer 45

1. Crossing Over
2. Independent Assortment
3. Random Fertilization

Question 46

What is “crossing over”?

Answer 46

Arms of homologous chromosomes cross over and exchange genes. Leads to genetic variation.

Question 47

What is nondisjunction and when does it occur?

Answer 47

Nondisjunction is when a chromosome pair (either sister chromatids or homologous pairs) fails to seperate at anaphase. It can occur during meiosis I or II.

Question 48

What’s trisomy21?

Answer 48

Down Syndrome. There are 3 copies of autosome 21.