chapter 10-2 notes cell divisionnewburyparkhighschool.net/stillwagon/biocp/current notes/chapter...

Chapter 10-2 Notes

Cell Division

I. Background Information

A. One of the major characteristics of living things is the ability to GROW

1. How? Not simply by growing larger but by dividing in half thus, an adult doesn't have bigger cells, they have more cells

You can grow too many cells!!!

Cancer

B. Chromosomes

1. Genetic information is passed on from one generation to the next through chromosomes

2. Every organism has a specific number of chromosomes

a. ex. carrots = 18 chromosomes

b. ex. humans = 46 23 came from MOM & 23 came from DAD

Before Replication

of DNA

After Replication

of DNA

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During normal mitotic cell division, a parent cell having four chromosomes will produce two daughter cells, each containing

1. two chromosomes.

2. four chromosomes.

3. eight chromosomes.

4. sixteen chromosomes.

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3. The chromosomes from Mom and Dad are considered “homologous” (homo means “same”)

4. Chromosomes are not visible in most cells except during cell division

G1 phase G2 phase M phase all of the

above

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Which of the following is a phase in the cell cycle?

1. G1 phase

2. G2 phase

3. M phase

4. all of the above

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The cell cycle is the

1. series of events that cells go through as they grow and divide.

2. period of time between the birth and the death of a cell.

3. time from prophase until cytokinesis.

4. time it takes for one cell to undergo mitosis.

15Answer Now

Cell Cycle

II. Cell Cycle

A. 3 main stages of the cell cycle:

1. Interphase: longest stage; preparation for cell division

2. Mitosis: nucleus divides into 2 nuclei, each with the same number and kind of chromosomes (DNA) as the parent cell

3. Cytokinesis: cytoplasm divides forming 2 distinct cells

B. Cell Cycle Overview

1. Interphase: quite long

a. Most of the cell’s timespent here

2. Cell Division: occurs quickly

a. Why is it important that the nucleus divides in mitosis?

i. It stores the DNA (information of life)

ii. All new cells need this information

iii. Why? – DNA and protein molecules that make up chromosomes are spread throughout the nucleus and are being used by cell

3. Before cell division, each chromosome is replicated (copied)

4. Then at the beginning of cell division (prophase), the chromatin condenses into compact visible “X” structures (chromosomes with sister chromatids)

5. After Chromosome Replication and Beginning of Prophase

a. Each chromosome is made up of 2 identical “sister” chromatids held together by a centromere.

Chromosome beforereplication

Chromosome AFTERReplication…

…

Centromere

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The structure labeled A in Figure 10–2 is called the

1. centromere.

2. centriole.

3. sister chromatid.

4. spindle.15Answer Now

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The structures labeled B in Figure 10–2 are called

1. centromeres.

2. centrioles.

3. sister chromatids.

4. spindles.

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C. Mini-Summary (up to this point)

1. DNA is being used/ giving instructions to make proteins…cell growing

2. Cell gets too big so the cell prepares to divide(mitosis)

3. DNA replicates (chromosome is copied)

4. What are the 3 steps of the cell cycle?

Interphase (G1, S, G2)

Mitosis (very short)

Cytokinesis

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Which of the following represents the phases

of mitosis in their proper sequence?

1. prophase, metaphase, anaphase, telophase

2. interphase, prophase, metaphase,

anaphase, telophase

3. interphase, prophase, metaphase,

telophase

4. prophase, anaphase, metaphase, telophase

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Mitosis

D. Mitosis is one, continuous event, but it can be described as happening in 4 phases:

1. Prophase

2. Metaphase

3. Anaphase

4. Telophase

Nuclear division

III. Interphase

A. Parts of Interphase

1. G 1 phase—cells grow, makes organellesand proteins –does its normal job/daily functions

2. S phase—DNA is copied

3. G 2 phase— more organelles are produced that are needed for cell division (prepares for mitosis)

G1 phase G2 phase S phase M phase

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When during the cell cycle is a cell’s DNA replicated?

1. G1 phase

2. G2 phase

3. S phase

4. M phase

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Chromatin

Cell

Membrane

Nucleus

Draw and Label

on Notes

B. Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy (sister chromosome) change to sister chromatids at the end of this phase.

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Chromosomes

Sister chromatids

Centromere

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Which of the following is a phase of

mitosis?

1. cytokinesis

2. interphase

3. prophase

4. S phase

15Answer Now

Mitosis Video

Copyright Pearson Prentice Hall

Section 10-2ProphaseSpindle

forming

Chromosomes (paired

chromatids)Centromere

Click to Continue

Mitosis

IV. Phases of Mitosis

**Remember, the cell is coming out of Interphase…

A. PROPHASE

1. Longest phase: 50-65% of total time required to complete mitosis

% Time Spent in Each Phase of Cell Cycle

78%

14%

4%

0.8% 0.2%3%

Interphase

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis

2. Chromatin condenses & chromosomes have been copied (S phase of Interphase) & now become visible as “X” structure (2 “sisterchromatids”)

3. Centrioles appear, separate, and move to

opposite sides of the cell

4. Spindle fibers (from centrioles) form and begin connecting to chromosomes at their centromeres

5. Nuclear envelope breaks down and the nucleolus disappears

Spindle forming

CentromereChromosomes(paired chromatids)

Draw and Label

on NotesCentrioles

Early Prophase

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Identify the structures labeled X.

1. nucleus

2. cell membrane

3. spindle fiber

4. chromosome

5. centriole

6. daughter cell

7. cytokinesis

8. cytoplasm 15Answer Now

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Centriole

Centriole

Spindle

Mitosis

Metaphase

B. METAPHASE

1. Fibers connect from the poles (end) of the spindle to the centromere of each chromosome

2. Chromosomes line up in the center of the cell (spindle fibers push and pull chromosomes)

Centriole

Spindle

Draw and Label

on Notes

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Individual chromosomes

Anaphase

Mitosis

C. ANAPHASE

1. Centromeres split, causing the sister chromatids to separate, becoming individual chromosomes

2. Chromosomes are pulled apart to oppositeends of the cell (kinetochore microtubulesshorten)

Individualchromosomes

Draw and Label

on Notes

kinetochore

microtubules

shorten

Non-

kinetochore

microtubules

Lengthen

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Identify the structures labeled Y.

1. nucleus

2. cell membrane

3. spindle fiber

4. chromosome

5. centriole

6. daughter cell

7. cytokinesis

8. cytoplasm 15Answer Now

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What is the role of the spindle during

mitosis?

1. It helps separate the

chromosomes.

2. It breaks down the

nuclear membrane.

3. It duplicates the DNA.

4. It makes the

chromosomes visible.

15Answer Now

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Nuclear envelope reforming

Telophase

Mitosis

D. TELOPHASE

1. Chromosomes uncoil into chromatin (tangle of dense material – no longer rods)

2. New nuclear envelope reforms around the chromatin

3. Spindle breaks apart

4. Nucleolus reappears in each new nucleus

5. The cell starts to pinch in

6. Mitosis ends

Draw and Label

on NotesNucleolus

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Cytokinesis

Cytokinesis

V. CYTOKINESIS – Last phase of cell cycle; division of the cytoplasm (including fluid and organelles)

End Result:

Two daughter cells

with the same

genetic

makeup

A. Animal cells: cell membrane pinches in & divides

1. Animal cells form an actin-myosin contractile ring within the equatorial region of the cell membrane that constricts to form the cleavage furrow.

Cell wallCell plate

B. Plant cells: a cell plate forms (new cell wall)

1. In plant cells, Golgi vesicle secretions form a cell plate or septum on the equatorial plane of the cell wall by the action of microtubules of the phragmoplast.

Animal Cell Mitosis Video

Plant Cell Mitosis Video

C. The cleavage furrow in animal cells and the phragmoplast in plant cells are complex structures made up of microtubules and microfilaments that aide in the final separation of the cells into two identicaldaughter cells.

Draw and Label

bottom figures

on Notes

Chromatin

0% 0% 0% 0%

One difference between cell division in

plant cells and in animal cells is that plant

cells have

1. centrioles.

2. centromeres.

3. a cell plate.

4. chromatin.

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A. B. C. D.

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Cell division is represented in Figure 10–1 by the letter

1. A.

2. B.

3. C.

4. D.

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VI. Then the cell returns to Interphase… and the process continues

Label all

phases on

diagram

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Which of the following is a correct statement about the events of the cell cycle?

1. Little happens during the G1 and G2 phases.

2. DNA replicates during cytokinesis.

3. The M phase is usually the longest phase.

4. Interphase consists of the G1, S, and G2 phases.

20Answer Now

0%

0%

0%

0%

List the correct order for

the diagrams.

1. A, C, D, B

2. B, D, C, A

3. C, A, B, D

4. D, A, C, B

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What would a

diagram of the next

step show?

Rank Responses

1

2

3

4

5

6

1

2

3

4

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Interphase

PROPHASE

chromatin

Chromosome (sister chromatids

held together by centromere)

METAPHASE

ANAPHASE

TELOPHASE

Finally… CYTOKINESIS

and back to INTERPHASE

Animal Mitosis Video

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The two main stages of cell division are

called

1. mitosis and interphase.

2. synthesis and cytokinesis.

3. the M phase and the S phase.

4. mitosis and cytokinesis.

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During which phase of mitosis do the

chromosomes line up along the middle of

the dividing cell?

1. prophase

2. telophase

3. metaphase

4. anaphase

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Tadpole Embryology Video

The cell’s volume increases.It becomes more difficult for the cell to get enoughoxygen and nutrients.

The cell has DNA overload.Each daughter cell receives its own copy of the parent cell’s DNA.

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Which of the following happens when a

cell divides?

1. The cell’s volume increases.

2. It becomes more difficult for

the cell to get enough oxygen

and nutrients.

3. The cell has DNA overload.

4. Each daughter cell receives

its own copy of the parent

cell’s DNA.15Answer Now

1 2 3 4 5 6

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What will the chromosome number of each

daughter cell shown be after mitosis?

1. 1

2. 2

3. 3

4. 4

5. 5

6. 6

15Answer Now

Amoeba Sisters Mitosis Video 10 notes

https://www.youtube.com/watch?v=f-ldPgEfAHI&index=18&list=PLwL0Myd7Dk1F0iQPGrjehze3eDpco1eVz

Two Pictorial Models of the Stages of the Cell Cycle –

Think-Pair-Share

Fill in the Stages of the cell cycle. On the left, the size of the pie is

proportional to the time spent in each phase. On the right, the icons

visually depict what happens at each stage.

G1S

G2

M

G1

SG2

M

Think-Pair-Share

What would happen if the stages of cell division do not occur in order? For example, what would happen if cytokinesis occurs before mitosis?