CELL REPRODUCTION

Mitosis & Cytokinesis Objective 4a: I can recognize the

stages of mitosis from diagrams.Objective 4b: I can put the stages of

mitosis in the proper order.Objective #4c: I can state what types

of cells undergo mitosis, and why.Objective #4d: I can list differences between how animal and plant cells

divide.

Introduction

Discuss the answers to the following questions with the person next to you: How is mitosis different from the phases of

interphase? What is the purpose of mitosis? What kinds of cells undergo mitosis? What are the phases of mitosis, and what

happens in each of them? So; what do you know?

Objectives #4a & 4b: Identifying Stages of Mitosis and Knowing the

Order of the Stages

• G2 Interphase cell—

preparing for mitosis. . .

How?

Prophase

Prophase Chromatin condenses into chromosomes

Sets of sister chromatids Nucleoli disappear Mitotic spindle begins to form as centrioles

move to opposite poles of the cell Nuclear envelope begins to fragment and

break down Microtubules of spindle (spindle fibers) attach

to centromeres of chromatids

Prophase (Early and Late)

Which of the following does NOT happen during prophase?

Chromoso

mes condense

...

Nucle

ar envelope st

arts ..

The mito

tic spindle st

art...

The spindle fibers

attach...

25% 25%25%25%1. Chromosomes condense into chromatin.

2. Nuclear envelope starts to break down.

3. The mitotic spindle starts to form.

4. The spindle fibers attach to the centromeres.

Metaphase

Metaphase Spindle fibers line sets of sister chromatids up

on the cell equator (middle of cell) Preparation for anaphase, where chromatids

get pulled apart

Which of the following is FALSE about metaphase?

Chromoso

mes are sti

ll se..

Siste

r chro

matids line u...

The centri

oles move

the ...

33% 33%33%1. Chromosomes are

still sets of sister chromatids attached to spindle fibers at their centromeres.

2. Sister chromatids line up along the cell equator.

3. The centrioles move the sister chromatids to the cell equator.

Anaphase

Anaphase Sister chromatids are pulled apart at their

centromeres Each sister chromatid is now considered a

chromosome Separated chromosomes are pulled to

opposite poles (ends) of the cell By end of anaphase, each pole (ends) of

cell has a complete set of chromosomes

Anaphase

Which of the following is FALSE concerning anaphase?

Chromoso

mes are sti

ll se..

Siste

r chro

matids are

pu...

Two new nuclei a

re fo

r...

33% 33%33%1. Chromosomes are still sets of sister chromatids at the end of anaphase.

2. Sister chromatids are pulled apart at their centromeres during anaphase.

3. Two new nuclei are formed at the end of anaphase.

Telophase

Telophase Two new daughter nuclei form at both poles

Nuclear envelopes reform around each set of chromosomes

Chromosomes uncondense back into chromatin Cytokinesis usually begins during telophase

or late anaphase Cleavage furrow appears (animal cells) or cell

plate appears (plants)

Telophase & Cytokinesis

What is the MAIN event that occurs during telophase?

Chromatids a

re pulle

d a...

Chromatin co

ndenses t

o...

Two new nuclei fo

rm at..

.

33% 33%33%1. Chromatids are pulled apart by their centromeres

2. Chromatin condenses to chromosomes

3. Two new nuclei form at each pole of the cell

The Phase Game!See if you can ID each phase of mitosis

below.

What phase of mitosis is this?

Prophas

e

Anaphase

Metaphase

33% 33%33%

1. Prophase2. Anaphase3. Metaphase

What phase of mitosis is this?

Anaphase

Inte

rphase

Prophas

e

33% 33%33%

1. Anaphase2. Interphase3. Prophase

Below correctly shows the stages of mitosis in order.

True

False

50%50%

1. True2. False

Cytokinesis: Plants vs. Animals

Differences in cytokinesis arise due to presence/absence of cell walls Animal cells: Can just pinch in two by a

process called cleavage Uses a ring of contractile proteins in its cell

membrane Like the drawstring on sweatpants pulled tight

enough to cut you in half Plant cells: Must build a new cell wall between

the two new nuclei Golgi sends out vesicles that builds the cell plate

What is the MAIN DIFFERENCE between cytokinesis in animal cells and plant cells?

Animal c

ells pinch

in tw

o...

Plant cell c

ytokinesis

mak..

Plant cells

use ch

loroplas

t..

33% 33%33%1. Animal cells pinch in

two; plant cells build a cell plate between two new nuclei.

2. Plant cell cytokinesis makes 4 new cells; animal cell cytokinesis only makes 2 new cells.

3. Plant cells use chloroplasts; animal cells do not.

Mitosis Exit Ticket #2

What stage of mitosis is shown?

Metaphase

Telophase

Anaphase

Prophas

e

25% 25%25%25%

1. Metaphase2. Telophase3. Anaphase4. Prophase

Which stage of mitosis is shown?

Prophas

e

Telophase

Metaphase

Anaphase

25% 25%25%25%

1. Prophase2. Telophase3. Metaphase4. Anaphase

The pictures of mitosis below are not in the correct order.

True

False

50%50%1. True2. False

What types of cells undergo mitosis, and why?

Body cells

, beca

use th

e...

Sperm

cells

, beca

use gu

..

Somatic c

ells, b

ecause

t..

33% 33%33%1. Body cells, because

they need to be small and make more identical cells.

2. Sperm cells, because guys make a LOT of them.

3. Somatic cells, because the daughter cells need to be genetically different from the parent cell.

Which is FALSE about cytokinesis?

Cytokinesis

finishes d

ividi..

Animal c

ells ca

n pinch in

...

Plant cells

have to

build ...

33% 33%33%1. Cytokinesis finishes

dividing the nucleus of the daughter cells.

2. Animal cells can pinch in two because they don’t have a cell wall.

3. Plant cells have to build a new cell wall between the two new nuclei to finish dividing completely.