Lesson Overview 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 Lesson Overview Cell Growth, Division, and Reproduction Review of Major Ideas: DNA packaging animationanimation DNA replication Animation #1#1 Animation #2#2

Lesson Overview 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 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 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 Lesson Overview Cell Growth, Division, and Reproduction Daily Review #4 5.What is a telomere and why is it possibly the “fountain of youth”? 6.Describe the prokaryote cell cycle 7.Describe the eukaryote cell cycle including what occurs in – Interphase – G1 – S – G2

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Mitosis Cell division Variable length of time 4 phases

Lesson Overview 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 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 Lesson Overview Cell Growth, Division, and Reproduction Telophase Chromosomes  chromatin Nuclear envelope re- forms Spindles break apart Nucleolus re- forms Mitosis complete

Lesson Overview 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 Lesson Overview Cell Growth, Division, and Reproduction Daily Review #5 8.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 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 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 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 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