Mitosis How do your cells divide? Ch. 6 and Ch. 7.

Mitosis

How do your cells divide?

Ch. 6 and Ch. 7

Chromosome Talk

A few words before we start…..

Haploid: (n) 1 set of unpaired chromosomes

Diploid: (2n)2 haploid sets of chromosomes(1 pair)

Why Do Cells Divide?

Surface area

Damaged cells

Sex cells

Cell Reproduction

is either sexual or asexual

Asexual Reproduction(one parent)

Binary Fission-

Budding

Vegetative Propagation

Regeneration

Advantages of Asexual Reproduction

Speed

Desirable Characteristics

Replacement

DNA Structure Ch. 9

Made up of nucleotidesThere are 3 parts to each

nucleotide–Deoxyribose sugar–Phosphate group–One of 4 Nitrogen bases

A

G

G

T

C

C

Nucleotide

Phosphate group

Deoxyribose

Sugar

Nitrogen Base

Nitrogen Bases

There are four possible nitrogen bases:

Adenine (A) Thymine (T)

Cytosine (C) Guanine (G)

A

G

T

C

Nitrogen Base Pairing

These bases always pair together in DNA:

Adenine (A) Thymine (T)

Cytosine (C) Guanine (G)

A

G

T

C

DNA Replication

Before a cell can divide the

DNA must replicate (make a copy

of itself)

DNA Replication

Making a new strand of DNA is actually quite easy.

Replication occurs in 3 easy steps…

1. DNA Unzips

An enzyme unzips the molecule

The enzymes breaks the hydrogen bonds that hold the nitrogen bases together.

A

G

G

T

C

C

DNA Replication DNA Unzips

A

G

G

T

C

C

DNA Replication DNA Unzips

A

G

G

T

C

C

DNA Replication DNA Unzips

A

G

G

T

C

C

DNA Replication DNA Unzips

A

G

G

T

C

C

DNA Replication DNA Unzips

A

G

G

T

C

C

DNA Replication DNA Unzips

Left Strandof Original DNA

Right Strandof Original DNA

2. Base Pairing

Complementary bases match with each DNA strand in the open helix

A

G

G

T

C

C

Left StrandOriginal DNA

Right StrandOriginal DNA

DNA Replication Base Pairing

A

G

G

T T

C

C

Left StrandOriginal DNA

Right StrandOriginal DNANew Right

DNA Strand

DNA Replication Base Pairing

A

G

G

T

C

T

C

C

Left StrandOriginal DNA

Right StrandOriginal DNANew Right

DNA Strand

DNA Replication Base Pairing

Left StrandOriginal DNA

Right StrandOriginal DNANew Right

DNA Strand

A

G

G

T

C

C

T

C

C

DNA Replication Base Pairing

Left StrandOriginal DNA

Right StrandOriginal DNANew Right

DNA Strand

A

G

G

T

C

C

T

C

C

A

New LeftDNA Strand

DNA Replication Base Pairing

Left StrandOriginal DNA

Right StrandOriginal DNANew Right

DNA StrandNew LeftDNA Strand

A

G

G

T

C

C

T

C

C

A

G

DNA Replication Base Pairing

Left StrandOriginal DNA

Right StrandOriginal DNANew Right

DNA StrandNew LeftDNA Strand

A

G

G

T

C

C

T

C

C

A

G

G

DNA Replication Base Pairing

3. DNA Zips Up

An enzyme zips the new molecules back up.

DNA Replication

Voila!Two identical strands of DNA!

T

C

C

A

G

G

T

C

C

A

G

G

T

C

C

A

G

G

DNA Replication Review

Step 1 Step 2 Step 3

Remember - All this takes place in INTERPHASE

G2

Now that DNA has replicated, we are ready to begin Mitosis (nucleusof the cell divides)

T

C

C

A

G

G

T

C

C

A

G

G

Parent CellDNA condenses into chromosomes

Chromosomes align on the equator

Chromosomes separate

DNA uncoils

Prophase

Metaphase

Anaphase

Telophase

MITOSIS

Cytokinesis

Cleavage (indention in cell membrane) or cell plate formation occurs.

Cell divides.

Animal Cell Plant Cell

The Cell Cycle

Mitosis Animation

Overview of the Cell Cycle

InterphaseC ell G row th

an d R ep lica tion

M itosisN u c lear D ivis ion

CytokinesisC ytop lasm D ivis ion

Cell Cycle

PMAT

It’s all about the chromosomes!– There are 46 in human body

cells– The number of chromosomes

remain constant during Mitosis

Which Cells Go Through Mitosis?

Growth

Repair

Work

Cells which help the body in:The cells are called autosomes

What happens if cell division gets out of control?

CANCERThe body doesn’t respond

normally to the body’s control mechanisms

p. 127, 138-139

Bone Cancer X-ray

Ovarian Cancer Cell Dividing

Skin Cancer

Mitosis Review

1. Is the beginning parent cell diploid or haploid

(2n or n)?

2. Are the daughter cells diploid or haploid (2n or n)?

More Mitosis Review

3. How many daughter cells are produced?

4. Are the resulting daughter cells different from the parent cell?

More Mitosis Review

5. Are the resulting daughter cells different from each other?

6. How many chromosomes are in a human parent cell?

7. How many chromosomes are in a human daughter cell?

More Mitosis Review

8.What types of cells are produced by mitosis?

9. Why (when) does a cell go through mitosis?