1. CELL REPRODUCTION Review of Biomolecules DNA Cell Reproduction Mitosis Nuclear/Cell Division + Cytokinesis Meiosis Sexual Reproduction; ‘2n’ to ‘n’

2. Biomolecules ??

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

4. 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

5. DNA STRUCTURE

6. *Handout Gene = allele = traits 1 from each parent 2m/6.5’ of DNA/cell

7. Clip on DNA…compacts tightly Visualizing Cell Processes DNA structure Chromosome Condensation

8. Cell Reproduction Introduction to chromosomes (the cells’ library of genetic material) Study Two Processes: Mitosis & Meiosis 1. Mitosis -cell division of Body (Somatic) cells. ‘2n’ diploid = complete set #? 2. Meiosis- division of sex cells (Gametes) egg, sperm ‘n’ Haploid = ? In humans Mitosis: everywhere ; Meiosis: reproductive organs only

9. 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)

10. Chromatin Partially “unraveled” Chromosomes (95%) Chromosome A ‘single’ structure … DNA*nucleosome proteins Chromatid 2 identical copies of a chromosome (attached) “sister chromatids” All refer to the cells’ DNA content at different stages

11. Homologous Chromosomes From Dad From Mom eye color locus (ex-’b’ blue) eye color locus (ex-’B’ 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

12. Chromosomes are counted on karyotypes Karyotype -Human Somatic Cell: #? 46 chromosomes 23 pairs ….’body’? 44 autosomes 22 pairs ….’sex’? 2 sex chromosomes 1 pair ….M/F? XX = female XY = male Allele: Different forms of a gene (Blue, brown eyes)

13. 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

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. 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

18. 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?

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

20. Telophase 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

21. 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

22. Summary of Mitosis

23. Plant Cell Cytokinesis

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