2 - Cell Division

Cell life cycle

a series of changes the cell experiences from the time it is formed until it divides

• Interphase

• Cell Division

Two major periods Cell life Cycle:

Interphase

Cell grows and carries out metabolic processes

Longer

How long is Interphase compared to Cell Division?

cell reproduces itself

What occurs during Cell Division?

DNA Replication

▪ Duplicates genetic material for cell division
▪ Happens near the end of Interphase

near end of Interphase

When does DNA replication occur?

to prepare genetic material for division into two cells

What is the purpose of DNA replication?

DNA Replication Process

DNA uncoils into two chains, each serving as a template

Into two nucleotide chains, each as a template

How does DNA uncoil during replication?

▪ A with T
▪ G with C

What is the base pairing rule in DNA replication?

Adenine, Thymine, Guanine, Cytosine

Nucleotides

Mitosis, Cytokinesis

Events of Cell Division

Mitosis

▪ Division of the nucleus
▪ Results in two daughter nuclei

Near the end of Mitosis

When does Cytokinesis begin?

2 daughter cells

What does Cytokinesis result in?

Cell Division

division of the nucleus

Cytokinesis

division of the cytoplasm

Interphase, Prophase, Metaphase, Anaphase, Telophase

Events of mitosis:

Prophase

Chromatin coils into chromosomes

• chromatids are held together by a centromere

• Centrioles assemble the mitotic spindle

• Nuclear envelope and nucleoli break down

becomes chromosomes

What happens to chromatin in Prophase?

make the spindle fibers

What do centrioles do in Prophase?

They disappear

What happens to the nuclear envelope and nucleoli in Prophase?

Metaphase

Chromosomes line up in the center
▪ On the metaphase plate

Center of the cell

Where do chromosomes line up in Metaphase?

Chromosomes

What forms a straight line in Metaphase?

Anaphase

Centromere splits
▪ Chromatids move to opposite ends
▪ Ends when chromosomes stop

splits

What happens to the centromere in Anaphase?

To opposite ends of the cell

Where do chromatids move in Anaphase?

When chromosomes stop moving

When does Anaphase end?

Telophase

▪ Chromosomes uncoil
▪ Spindles disappear
▪ Nuclear envelope reforms
▪ Nucleoli reappear

uncoil

What happens to chromosomes in Telophase?

disappear

What happens to spindles in Telophase?

Nucleoli

What reappears in each daughter nucleus?

Cytokinesis

▪ Cytoplasm divides
▪ Starts in late anaphase, ends in telophase
▪ Cleavage furrow forms
▪ Results in two daughter cells

starts late anaphase, ends in telophase

When does Cytokinesis start and end?

Cleavage Furrow

(contractile ring of microfilaments) forms to pinch the cells into two parts

2 daughter cells

What does Cytokinesis produce?

Mitosis and Cytokinesis

▪ Usually occur together
▪ Sometimes cytoplasm isn’t divided

Binucleate or Multinucleate cells form

What happens if cytokinesis doesn’t occur?

Liver and skeletal muscle

Where are binucleate or multinucleate cells commonly found?