The Cell Cycle/Division/Mitosis

Unit 4

The Cell CycleInterphase

MitosisCytokinesis

CyclinCDK

Click here for definition

(Synthesis)

Cell Cycle ExpandedM phase has 4 stages plus Cytokinesis!!

Movie

Interphase Performs normal activities

for life.

• G1-Grows• S-Replicates/synthesizes the DNA(genetic material)

• G2-Grows

DNA is in the chromatin state (kind of like spaghetti)

What are the stages/phases of Mitosis?

Centrioles appear

Centrioles move

Spindle fibersgrow from

the centrioles

center of the cell

(DNA/Chromosomes)

•Two new nuclei form •Cell membrane pinches in

Cytokinesis This process ends the cell cycle.

Cytokinesis

new

CELLS AFTER COMPLETING THE CELL CYCLE

How is mitosis different in plant and animal cells?

During Telophase and Cytokinesis in

Plant cell--a cell wall forms between the two daughter cells

Animal cell --cell membrane pinching in for cytokinesis no cell wall forms

Interphase Prophase Metaphase

Anaphase Telophase

Animal Cell

Plant Cells

Understanding Chromosomes

The genetic material inside the nucleus goes by many different names. The name depends on how it is packaged or where it is located in the cell.

Understanding Chromosomes

Protein

Sister ChromatidsNucleus

Tightly coiled DNA strand

Centromere

Chromosome number during the Cell Cycle

2 4 4 4

2

2

Interphase

Cytokinesis

Asexual Reproduction

When one organism produces one or more new organisms that can live on their own.

•Reproduction without sperm and egg uniting.

Binary fissionParent cell splits in two, producing identical daughter cells.

Not mitosis because there is no nucleus but the DNA does get copied and transferred to the next generation.

BuddingOrganisms produce buds “mini-me” that will grow into a genetically identical adult.

Bud

Yeast (unicellular) Hydra (Multicellular)

RegenerationNew tissue growth at the site of a wound

Propagating Plants from Stem Cuttings (a type of Regeneration)

Why Choose Asexual Reproduction?--Advantages

• Rapid population growth• No fertilization of an egg

cell-no need of a partner.• Organism can remain in

one particular place • Genetically identical

copies of the parent-- adapted to the environment.

Each spot on this Petri dish is a bacterial colony started by one bacterium.By the time a colony is visible to the human eye, it consists of at least one million cells.

Disadvantages of Asexual Reproduction?

• No genetic difference, change is environment can be deadly to entire population.

• Any mutations or "bad" qualities will be passed on.

Streptococcus bacteria.

Strep Throat infection

Antibiotic change the environment for the bacteria that cause Strep-throat. Inmost casesall of thebacteriawill die.

• CDK- a molecule that plays a key role in controlling the cell cycle.

• Cyclin-regulates CDK

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Modified by R. O’Connor 10/10