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1. Cells grow larger and reproduce

1. Cells grow larger and reproduce. 2. Development of whole organism from single cell (zygote). What controls these processes?. 1. Cells grow larger and reproduce. 2. Development of whole organism from single cell (zygote). 3. Worn-out cells are replaced.

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1. Cells grow larger and reproduce

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  1. 1. Cells grow larger and reproduce

  2. 2. Development of whole organism from single cell (zygote)

  3. What controls these processes? 1. Cells grow larger and reproduce 2. Development of whole organism from single cell (zygote) 3. Worn-out cells are replaced. DNA - key molecule that carries information to direct all cell functions

  4. THE PATH OF PROTEIN SYNTHESIS DNA 1 mRNA nucleus amino acids 2 ribosome mRNA 3 protein cytoplasm

  5. C G G C DNA Genetic information is encoded in the sequence of bases A T G C G C A T T A Code is translated to amino acid sequence of proteins CTGA C G A T G C T A T A G C G C A T T A

  6. Chromatin = DNA with associated proteins Genome = complete set of chromosomes for an organism • Chromosomes contain a very long DNA molecule with thousands of genes

  7. The large, complex chromosomes of eukaryotes duplicate with each cell division • A eukaryotic cell has many more genes than a prokaryotic cell Figure 8.4A

  8. 1. Original DNA molecule unwinds. 2. New DNA strands are synthesized from the two original strands.

  9. a DNA in uncondensed form

  10. a DNA chromatin duplicated chromosome cell DNA replication... …has this effect at chromosomal level unduplicated chromosome (not actual shape) duplicated chromosome b sister chromatids

  11. Sister chromatids • When chromosomes are duplicated, sister chromatids are produced Centromere telomere Figure 8.4B

  12. Human bands Figure 8.19x1

  13. Human karyotype Figure 8.19x2

  14. Chromosomeduplication • Two daughter cells are produced • Each has a complete and identical set of chromosomes • When the cell divides, the sister chromatids separate Sister chromatids Centromere Chromosomedistributiontodaughtercells Figure 8.4C

  15. cell DNA nucleus 1. REPLICATION DNA DNA 2. MITOSIS DNA DNA 3. CYTOKINESIS DNA DNA

  16. DNA Mitotic Phase (M) DNA DNA DNA Interphase DNA DNA Cytokinesis Mitosis G1 Cell growth G2 Cell growth preparation for division Interphase S DNA replication DNA DNA DNA Interphase

  17. Eukaryotic cell division consists of two stages: • Mitosis • Cytokinesis

  18. INTERPHASE PROPHASE Centrosomes(with centriole pairs) Early mitoticspindle Centrosome Fragmentsof nuclearenvelope Kinetochore Chromatin Centrosome Spindlemicrotubules Nucleolus Nuclearenvelope Plasmamembrane Chromosome,consisting of twosister chromatids Figure 8.6

  19. METAPHASE ANAPHASE TELOPHASE AND CYTOKINESIS Cleavagefurrow Nucleolusforming Metaphaseplate Nuclearenvelopeforming Spindle Daughterchromosomes Figure 8.6 (continued)

  20. Cytokinesis differs for plant and animal cells • In animals, cytokinesis occurs by cleavage • which pinches the cell apart Cleavagefurrow Cleavagefurrow Contracting ring ofmicrofilaments Figure 8.7A Daughter cells

  21. Cell plateforming Wall ofparent cell Daughternucleus • In plants, vesicles build a new cell plate Cell wall New cell wall Vesicles containingcell wall material Cell plate Daughtercells Figure 8.7B

  22. E. coli dividing Figure 8.3x

  23. BINARY FISSION IN BACTERIA cell wall two daughter cells chromosome cell membrane parent bacterial cell

  24. Review of functions of mitosis: • Mitotic cell division functions in: • Growth (here, onion root) Figure 8.11A

  25. Deadcells • Cell replacement (seen here in skin) Epidermis, the outer layer of the skin Dividingcells Dermis Figure 8.11B

  26. Asexual reproduction (seen here in a hydra) Figure 8.11C

  27. Development (Sea urchin ) Figure 8.0x

  28. Mitotic spindle Figure 8.6x2

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