Cell Cycle - Chpt 8

Life cycle

Sequence of life stages

Sexual reproduction

Union of a sperm and an egg

Asexual reproduction

Production of offspring by a single parent

Genome

One copy of genetic information

Prokaryotes go through…

Binary fission for cell division

Before cell division, eukaryotes are in a

“Chromatin state”, DNA and protein molecules d

Chromatin

Is organized by nucleosomes

Nucleosomes

Each consists of DNA wrapped around 8 proteins called histones

DNA connects to nucleosomes like

“Beads-on-string”

As a cell prepares to divide…

Chromatin coils up, and form visible chromosomes

Chromosomes replicate producing…

Sister chromatids ( with identical genes )

Cell cycle consists of…

Interphase,prophase ( early and late), metaphase,anaphase,telophase/cytokinesis

Interphase

Most of cell time 905,”resting stage”,chromosomes duplicate

How many subphases does interphase have

3, G1,S,G2

Subphase - G1

Before DNA synthesis begins,cell increases its supply of protein,increase in organelles,grows in size

Subphase - S

DNA synthesis occurs ( one chromosomes then two sister chromatids)

Subphase - G2

Ending time of DNA synthesis occurs , 2 processes

Mitosis

(G2 Subphase) - molecules/content divide

Cytokinesis

( G2 Subphase) - cytoplasm divides

Early Prophase

Changes occur in nucleus and cytoplasm ( but the cytoplasm does not divide)

Early Prophase Chromatin fiber

Are more coiled, forming visible chromosomes

Early prophases chromosomes consist of…

2 sister chromatids

Early prophase miotic spindles begin to…

Form as microtubules grow away from the microtubules-organizing centers ( MTOC)

Prometaphase

AKA late prophase, the nuclear envelope breaks,spindle fibers attach to kinetic horse on chronometer, chromosomes are agitated

Metaphase

A spindle is formed,with opposite MTOC

Anaphase

The centromeres come apart,separating the sister chromatids ( one separated they area” daughter chromosomes”)

Anaphase chromosomes are…

Pulled ( ny ATP) to the oppposite poles, the cell elongates

Telophase

Cell elongation continues, nuclear envelopes start to appear,fiber uncoil,spindle disappear

Telophase is an equal of one nucleus…

Into two genetically identical daughter nuclei

Cytokinesis

The division of the cytoplasm

Cleavage furrow

Animal cell

Cell plates

Plants cells