Lesson Overview Cell Growth, Division, and Reproduction

Prokaryote vs. Eukaryote• One starting point• Proceeds in opposite directions• Attach to different parts of cell membrane• Cell divides • Begins in many different places

• Proceeds in both directions• Enzymes check for damage or

mistakes and repair• Mistakes can be missed and

passed on• Finished copies remain close until

prophase of mitosis

Lesson Overview Cell Growth, Division, and Reproduction

Review of Major Ideas:• DNA packaging animation• DNA replication

• Animation #1• Animation #2

Lesson Overview Cell Growth, Division, and Reproduction

Telomeres• Ends of chromosomes• Hard to replicate

• Likely to be lost• Shorten with each cell division

• Older cells, shorter telomeres• Telomerase

• Adds short repeats to ends• Decreases likelihood of loss• Lengthens telomeres

• Increases life of DNA

Lesson Overview Cell Growth, Division, and Reproduction

The Prokaryotic Cell Cycle

• Definition• Asexual reproduction

• Chromosome replicates• Attach to cell membrane• Fibers form and constrict cell

• Divide cytoplasm• 2 identical daughter cells

Lesson Overview Cell Growth, Division, and Reproduction

The Eukaryotic Cell Cycle• Interphase• G1

• Gap• Cell growth

• S• Synthesis• DNA replication

• G2• Shortest• Organelles and

molecule synthesis• M

• Mitosis• 2 identical daughter

cells

Lesson Overview Cell Growth, Division, and Reproduction

Daily Review #45. What is a telomere and why is it possibly the

“fountain of youth”?6. Describe the prokaryote cell cycle7. Describe the eukaryote cell cycle including what

occurs in – Interphase–G1–S–G2

Lesson Overview Cell Growth, Division, and Reproduction

Mitosis• Cell division• Variable length of time• 4 phases

Lesson Overview Cell Growth, Division, and Reproduction

Prophase• Longest• In nucleus

– Chromatids, sister chromatids

– Centromere– Chromosome– Chromosomes coil further– Nucleolus disappears– Nuclear envelope breaks

down• In cytoplasm

– Spindle fibers– Centrioles

• Overall

Lesson Overview Cell Growth, Division, and Reproduction

Metaphase and Anaphase• Metaphase

– Few minutes– Centromeres line up– Spindle fibers

• Anaphase– Sister chromatids– Chromatid =

chromosome– 2 separate groups

Lesson Overview Cell Growth, Division, and Reproduction

Telophase• Chromosomes

chromatin• Nuclear envelope

re-forms• Spindles break

apart• Nucleolus re-

forms• Mitosis complete

Lesson Overview Cell Growth, Division, and Reproduction

Cytokinesis• Final part of M phase• Simultaneous with

telophase• Animal cells

– Cell membrane– Cytoplasm– Each own nucleus

and organelles• Plant cells

– Cell plate– Cell membrane– Cell wall

• Animation

Lesson Overview Cell Growth, Division, and Reproduction

Daily Review #58. Find a cell in your microscope that shows each of

the following phases:• Interphase• Prophase• Metaphase• Anaphase• Telophase• Cytokinesis - What is the difference in this stage

between animal and plant cells?

Lesson Overview Cell Growth, Division, and Reproduction

When does a cell divide?• Cell isolation• Cyclins

–Signal cell to divide–First starts spindle fiber formation–Groups of proteins

Lesson Overview Cell Growth, Division, and Reproduction

Regulatory proteins• Internal regulators

– Inside cell– Prepare cell for mitosis– Examples

• External regulators– Outside the cell– Change speed of cell cycle– Stimulate embryonic development– Stimulate wound healing– Surface proteins signal neighboring cells

Lesson Overview Cell Growth, Division, and Reproduction

Apoptosis• Cell death• Series of steps

– Cell and chromatin shrink– Cell membrane breaks up– “Eaten” by neighbors

• Occurs– Accident– Injury– Development

• Out of control in diseases

Lesson Overview Cell Growth, Division, and Reproduction

Cancer•Uncontrolled cell growth•Doesn’t respond to signals•Tumor

–Benign–Malignant

•Causes–Smoking, chewing tobacco–Radiation–Defective genes–Viral infection

• Can cause

– Absorb nutrients– Block nerves– Prevent organ functioning

• Treatments–Removal–Radiation therapy–Chemotherapy