1 1 Asexual Reproduction presents: Mrs. Stewart Honors Biology: Cell Growth and Division.

1 1

Asexual Reproduction presents:

Mrs. Stewart

Honors Biology: Cell Growth and Division

11/01/11

MITOSIS

A CELL GROWTH

AND DIVISION

PRODUCTION

How do little elephants grow up to be BIG elephants?

BELL WORK

Are the cells of the adult elephant larger than those of the baby?

BELL WORK

STANDARDS CLE 3210.4.2 Describe the

relationships among genes, chromosomes, proteins, and hereditary traits.

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OBJECTIVES Evaluate the reasons for asexual

reproduction in organisms

Differentiate between the different stages of the cell cycle in terms of order of occurrence, and chromosome location

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LET’S REVIEW:CHROMOSOMES

What do they look like?

How many do humans have?

They look like an “X” just before the cell divides and an “I” after they divide.

• 46 (23 pairs)

• (23 from mom, 23 from dad)

CELL DIVISION IN EUKARYOTES

There are two different types of cell division

Which type is performed depends on the kind of “daughter cells” that

are desired

Mitosis = identical daughter cells with same amount of DNA

Meiosis = genetically different daughter cells with half the amount of DNA

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Somatic CellsEvery cell in the body

EXCEPT reproductive cellsHave all 46 chromosomes

GameteSexual reproduction cells

(Example: sperm for males, Ova/eggs for females)

have half the amount DNA (23 chromosomes)

WHICH CELLS DO MITOSIS? Somatic

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OR

Gametes

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Why do animals shed their skin?T

HIN

K – P

AIR

- SH

AR

E

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How does a cut heal? T

HIN

K – P

AIR

- SH

AR

E

Three reasons why cells reproduce by asexual reproduction:

1. Growth 2. Repair 3. Replacement

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ASEXUAL REPRODUCTION

- REQUIRES ONLY ONE PARENT/CELL

- MAKES SOMATIC CELLS

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At what point does it become necessary for a

cell to divide?

When the cells resources are under too great a strain from it’s size

• Cell Membrane not large enough to maintain needs coming in/going out

• DNA, used for protein synthesis, cant keep up with demands

• Organelles unable to keep up with demands (ie: waste removal)

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CE

LL

CY

CL

E2 Main Stages:

1. Interphasea)G1b)Sc) G2

2. Mitosis – M phasea)Prophaseb)Metaphasec) Anaphased)Telophasee)Cytokinesis

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Which phase

does the cell

spend the most

time in?

Interphase

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Create yo

ur g

raph

ic org

anizer

INTERPHASE ANAPHASE

PROPHASE TELOPHASE

METAPHASE CYTOKINESIS

CELL CYCLE

ASSIGNMENT:

Create a mnemonic device to help you remember –

I-P-M-A-T-C

We will vote on the best one tomorrow in class. Winner gets a two day “slack” pass.

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ANIMATION Mitosis animation – mcgraw-hill

Cell cycle animation – cells alive website

Mitosis – sumanas (step by step w/ tutorial and quiz)

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Interp

hase

• Time between cell divisions• 90% of a cell’s life

3 phases:1. G1: Growth and everyday

activities

2. S: DNA replication

3. G2: preparation for Mitosis (production of necessary proteins/organelles)

The process of dividing the nucleus

to create two daughter cells, identical to the

mother cell

Mitosis

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Mitosis• Creates two daughter cells that are

identical to each other AND identical to the parent cell

• Creates diploid cells (two sets of chromosomes in each daughter cell)

• Allows organisms to grow• Allows organisms to replace

damaged/worn out cells• P-M-A-T-C

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PR

OP

HA

SE

•The DNA (chromatin) organizes into chromosomes

•The nuclear membrane disappears

•Centrosomes (centrioles) move to opposite ends of cell

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ME

TAP

HA

SE

Chromosomes attach to spindle fibers (by their centromeres), and line up at the center of the cell

Spindle Fibers – microtubules that help separate chromosomes during division

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AN

AP

HA

SE

Chromosomes separate at the

centromere, and the sister chromatids are

pulled toward opposite ends of the cell.

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TE

LO

PH

AS

E

Chromosomes disorganize and

the nuclear membrane

begins to reform.

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CY

TO

KIN

ES

IS

The division of the cell cytoplasm, usually beginning during Telophase and finalizing the production of two new daughter cells.

Each new cell will have about ½ of the cytoplasm and organelles of the parent cell.

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CLEAVAGE FURROW VS.

CELL PLATE

ANIMAL

Cleavage furrow indentation of the cell membrane to form two separate

cells

Plants

Cell plate A cell wall is rigid and cannot

flexibly move and pinch together to separate the newly formed cells. So, a cell plate forms

between the two new cells. This cell plate will harden and become

a cell wall for each.

CY

TO

KIN

ES

IS

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CLEAVAGE FURROW VS.

CELL PLATE

REMEMBER:

Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

I PLAY MUSIC AT THE CLUB11/01/11

I P M A T C

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CREATE YOUR POST-IT NOTE

PAPER

MUSICAL CHAIRS

An

imal M

itosis -- R

eviewInterphase

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis

Plan

t Mito

sis -- Review

Interphase

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis

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Y

Reflection:

Identify the following:• Structure X• Structure Y

Which stage of the cell cycle is shown?