Cell Reproduction Part 1Cell Reproduction Part 1

“All cells come from pre-existing cells.”

Cells must divide for...Cells must divide for...

GrowthGrowthRepairRepairReproductionReproduction

The Star of Our ShowThe Star of Our Show

Prior to division, chromosomes are Prior to division, chromosomes are duplicated.duplicated.

A single stranded chromosome A single stranded chromosome becomes a double stranded becomes a double stranded chromosome.chromosome.

The two strands are The two strands are IDENTICALIDENTICAL

The identical The identical strands are called strands are called sister chromatids.sister chromatids.

They are held They are held together by a together by a centromerecentromere..

centromere

chromatids

The Cell CycleThe Cell Cycle

The life of a eukaryotic cell The life of a eukaryotic cell is traditionally shown as a is traditionally shown as a cycle.cycle.

The Cell CycleThe Cell Cycle

Cell Cycle Cell Cycle SummarySummary

G1 – Cell growth phaseG1 – Cell growth phase S – New DNA is synthesizedS – New DNA is synthesized G2 – Preparation for cell G2 – Preparation for cell

divisiondivision M & C - Cell divisionM & C - Cell division

MitosisMitosisDivision of the nucleus to Division of the nucleus to form two new nuclei with form two new nuclei with the same number and the same number and type of chromosomes as type of chromosomes as the parent cell.the parent cell.

CytokinesisCytokinesis

The division of the The division of the cytoplasm to form cytoplasm to form two new cells.two new cells.

Before MitosisBefore Mitosis

InterphaseInterphase is the is the period between cell period between cell division. (G1, S & G2)division. (G1, S & G2)

Cell growth.Cell growth. Chromosomes Chromosomes

duplicate.duplicate. Synthesis of Synthesis of

organelles and organelles and materials needed for materials needed for cell division.cell division.

Now it’s Mitosis Time!Now it’s Mitosis Time!

Cells spend 90% of their lives Cells spend 90% of their lives during Interphase. So, once during Interphase. So, once we get to Mitosis – it’s GO we get to Mitosis – it’s GO

time!time!

ProphaseProphase

Chromatin Chromatin condenses into condenses into chromosomes.chromosomes.

The nuclear The nuclear membrane membrane disappears.disappears.

MetaphaseMetaphase

Chromosomes Chromosomes line up across the line up across the equator, or equator, or center, of the cell.center, of the cell.

AnaphaseAnaphase

Sister Sister chromatids chromatids are pulled to are pulled to opposite sides opposite sides of the cell & of the cell & away from away from each other.each other.

TelophaseTelophase

New nuclear New nuclear membranes membranes appear.appear.

Cytokinesis begins.Cytokinesis begins.

Chromosomes Chromosomes uncoil.uncoil.

After MitosisAfter Mitosis Cells undergo CytokinesisCells undergo Cytokinesis

– The cytoplasm of the cell is The cytoplasm of the cell is divided in halfdivided in half

– The cell membrane grows to The cell membrane grows to enclose each cellenclose each cell Results in TWO genetically Results in TWO genetically IDENTICAL cellsIDENTICAL cells

Animal Cell CytokinesisAnimal Cell Cytokinesis

The cell The cell membrane membrane is pinched is pinched in half by a in half by a belt of belt of protein protein threadsthreads

Plant Cell CytokinesisPlant Cell Cytokinesis A cell plate A cell plate

forms in the forms in the center of center of the dividing the dividing cell then cell then fuses to fuses to make a new make a new cell wall.cell wall.

1. Name That Phase!1. Name That Phase!

2. Name That Phase!2. Name That Phase!

3. Name That Phase!3. Name That Phase!

4. Name That Phase!4. Name That Phase!

LABEL THIS!LABEL THIS!

5. What is A?

6. What is B?

A

B

Question #7Question #7

A human cell contains 46 A human cell contains 46 chromosomes.chromosomes.

How many chromosomes will How many chromosomes will each of its daughter cells have each of its daughter cells have following mitosis?following mitosis?

Question #8Question #8__________ is the __________ is the division of the nucleus division of the nucleus to form two new nuclei to form two new nuclei with the same number with the same number and type of and type of chromosomes as the chromosomes as the parent cell.parent cell.

Question #9Question #9

__________ is the __________ is the division of the division of the cytoplasm to form cytoplasm to form two new cells.two new cells.

Question #10Question #10

Chromosomes must ____________ Chromosomes must ____________ prior to mitosis.prior to mitosis.

A. split in halfA. split in half

B. duplicateB. duplicate

C. dance aroundC. dance around

D. pass the AIMS testD. pass the AIMS test

1. Name That Phase!1. Name That Phase!

PROPHASE

2. Name That Phase!2. Name That Phase!

TELOPHASE

3. Name That Phase!3. Name That Phase!

METAPHASE

4. Name That Phase!4. Name That Phase!

ANAPHASE

LABEL THIS!LABEL THIS!

5. What is A?

6. What is B?

A

B

CENTROMERE

SISTER CHROMATIDS

Question #7Question #7

A human cell contains 46 A human cell contains 46 chromosomes.chromosomes.

How many chromosomes will each How many chromosomes will each of its daughter cells have following of its daughter cells have following mitosis?mitosis?

ANSWER: 46

Question #8Question #8__________ is the __________ is the division of the nucleus division of the nucleus to form two new nuclei to form two new nuclei with the same number with the same number and type of and type of chromosomes as the chromosomes as the parent cell.parent cell.

MITOSIS

Question #9Question #9

__________ is the __________ is the division of the division of the cytoplasm to form cytoplasm to form two new cells.two new cells.

CYTOKINESIS

Question #10Question #10

Chromosomes must ____________ Chromosomes must ____________ prior to mitosis.prior to mitosis.

A. split in halfA. split in half

B. duplicateB. duplicate

C. dance aroundC. dance around

D. pass the AIMS testD. pass the AIMS test

*

B B