lesson overview lesson overview cell growth, division, and reproduction prokaryote vs. eukaryote one...
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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