1. CELL REPRODUCTION Review of Biomolecules DNA Cell Reproduction Mitosis (Asexual Reproduction) Meiosis (Sexual Reproduction)

2. Biomolecules ??

3. Proteins Amino Acids (20) Nucleic Acids Nucleotides DNA/RNA Carbohydrates Monosaccharides Sugars Lipids Fatty Acids

4. Cell ReproductionIn This Unit: 1. Introduction to chromosomes (the cells’ library of genetic material) 2. Study Mitosis and cell division of Body (Somatic) cells 3. Examine how sex cells (Gametes) form through a process called meiosis

5. P/S: Reasons for Cell Reproduction 1. Replace/Maintenance (skin, blood, digestive) 2. Growth 3. Repair (scrape knee, break bone) 4. Reproduction of species: pass down genetic material for continuation of the species (mutations/adaptions/natural selection)

6. Structure of DNA Stores Genetic Information A Double helix ladder of connected nucleotides forming a sugar-phosphate “backbone” and nitrogen base “steps” Each nucleotide of DNA consists of: A sugar “deoxyribose” A phosphate A nitrogenous base: AdenineThymine CytosineGuanine

7. DNA STRUCTURE

8. Clip on DNA…compacts tightly Visualizing Cell Processes DNA structure Chromosome Condnesation

9. *Handout

10. Chromosomes are counted on karyotypes Karyotype Of a Human Somatic Cell: 46 chromosomes 23 pairs 44 autosomes 22 pairs 2 sex chromosomes 1 pair XX = female XY = male Allele: Different forms of a gene (Blue, brown eyes)

11. Chromatin Partially “unraveled” Chromosomes Chromosome A ‘single’ structure … DNA*nucleosome proteins Chromatid 2 identical copies of a chromosome (attached) All refer to the cells’ DNA content at different stages

12. TWO TYPES OF CELLS:SOMATIC and GAMETES  SOMATIC:(Body Cells) (Body cells: skin/muscle/liver/bone/brain/blood) Diploid Cells (2n): The # of chromosomes in a somatic cell 2n = ? in humans…varies/species  GAMETES:(Sex Cells) (Sex cells = Gametes = Humans?)  23 Sperm + 23 Egg = 46 Zygote (The fertilized egg) Plants? Haploid Cells (n): The # of chromosomes in a sex cell n = 23 in humans (half a complete set) 46

13. Homologous Chromosomes From Dad From Mom eye color locus (ex-blue) eye color locus (ex-brown) hair color locus hair color locus CENTROMERE ALLELE FOR EYE COLOR _____ Sister Chromatids (identical) *Nonsister Unreplicated Chromosome, when copied = 2 chromatids Held together by a centromere- form a replicated chromosome Homologous chromosomes: 23 PAIRS (From mother/father …similar in size/shape and centromere position

14. The Making of New Prokaryotes: Binary Fission (asexual) (see notepage) DNA attached to the inner membrane DNA (plasmid) copies New cell wall forms Then splits in two, creating two bacteria with IDENTICAL DNA. replicates in ~20minutes

15. Eukaryotic Cell Cycle: Repeating set of events that make up the life of a cell Interphase + PMAT (Mitosis) + Cytokinesis Cytokinesis: Cytoplasm Divides G o Phase Mitosis + Cytokinesis

16. Cell Cycle: An Interactive Animation

17. Cell Cycle Checkpoints- The Controls Cyclins and cyclin dependent kinases (CDK’s) control the cell cycle. They regulate gene expression to allow for cell replication and division. Depending on the presence and action of these proteins, the cell cycle can be speedy or slow, and it may even halt altogether. *PDGF- Platelet Derived Growth Factor- Wound healing

18. Mitosis “Maturation” Promoting Factor (MPF) Platelet-derived Growth Factor (PDGF) Cancer Disruption in cell cycle control 3A3 Cyclins and cyclin-dependent kinases control the cell cycle 3.A.2aThe cell cycle is a complex set of stages that is highly regulated with checkpoints, which determine the ultimate fate of the cell. Internal controls or checkpoints, internal and external signals provide stop & go signs at the checkpoints CELL CYCLE CONTROL Cell Cycle Control and Checkpoint Activity 6.12Cells Alive!

21. P53 pp,.43 clip ONCOGENES: Normally stimulate cell growth SUPPRESSOR GENES Normally inhibit cell growth REPAIR GENES Normally limit mutations Genes are Transcribed Mutations Methylation (Hyper or Demethylation) Transcription factors miRNA “Normal Control” GROW/DIVIDE when needed (Repair, growth) STOP for internal or external controls. Growth Factors Density dependent Anchorage dependent p53 protein: Transcription Factor for checkpoint control genes “the guardian of the genome”, regulates the cellular response to stress and cancer Abnormal

22. PROPHASE Chromosomes Condense The nuclear envelope disappears (dotted line = breakdown or forming The centrioles move to opposite poled The spindle starts to form, growing out of the centrioles towards the chromosomes

23. Metaphase Chromosomes line up on the equator of the cell Spindle fibers are attached to the centromeres Human Cell- how many Will be lined across?

24. Anaphase Centromeres divide Spindle fibers contract and the chromosomes are pulled to opposite poles

25. Telephase In telophase the cell actually divides The chromosomes are at the poles of the spindle The spindle disintegrates The nuclear envelope reforms around the two sets of chromosomes Set for cytokinesis to occur

26. Cytokinesis Division of cytoplasm and its contents Results in 2 daughter cells Animal cells- Furrow formed by microfilaments- pinches plasma in half “cleavage furrow” Plant cells- a new cell wall made of cellulose forms between the 2 new nuclei

27. Summary of Mitosis

28. Plant Cell Cytokinesis

30. Mitosis/Meiosis Animation http://www.pbs.org/wgbh/nova/miracle/divi_flash.html BRIEF INTRO MEIOSIS/COMPARISON TO MITOSIS

31. MITOSIS Mitosis + Cytokinesis = 2 new cells with the same genetic information as the original cell

32. Mitosis (body cell) vs. Meiosis (sex cell)