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1. Cells grow larger and reproduce. 2. Development of whole organism from single cell (zygote). 3. Worn-out cells are replaced. What controls these processes?. C. G. G. C. DNA Genetic information is encoded in the sequence of bases. A. T. G. C. G. C. A. T. T. A.
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1. Cells grow larger and reproduce 2. Development of whole organism from single cell (zygote) 3. Worn-out cells are replaced. What controls these processes?
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
THE PATH OF PROTEIN SYNTHESIS DNA 1 mRNA nucleus amino acids 2 ribosome mRNA 3 protein cytoplasm
Chromatin = DNA with associated proteins Genome = one complete set of chromosomes for an organism • Chromosomes consist of a long DNA molecule with thousands of genes
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
1. Original DNA molecule unwinds. 2. New DNA strands are synthesized from the two original strands.
a DNA chromatin duplicated chromosome cell DNA replication... …has this effect at chromosomal level unduplicated chromosome (not actual shape) duplicated chromosome b sister chromatids
Sister chromatids • When chromosomes are duplicated, sister chromatids are produced Centromere telomere Figure 8.4B
Human bands Figure 8.19x1
Human karyotype Figure 8.19x2
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
cell DNA nucleus 1. REPLICATION DNA DNA • Eukaryotic cell division consists of two stages: • Mitosis • Cytokinesis 2. MITOSIS DNA DNA 3. CYTOKINESIS DNA DNA
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
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
METAPHASE ANAPHASE TELOPHASE AND CYTOKINESIS Cleavagefurrow Nucleolusforming Metaphaseplate Nuclearenvelopeforming Spindle Daughterchromosomes Figure 8.6 (continued)
Mitotic spindle Figure 8.6x2
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
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
Binary fission - example: E. coli dividing Figure 8.3x
BINARY FISSION IN BACTERIA cell wall two daughter cells chromosome cell membrane parent bacterial cell
Review of functions of mitosis: • Mitotic cell division functions in: • Growth (ex. onion root) Figure 8.11A
Deadcells • Cell replacement (ex. skin) Epidermis, the outer layer of the skin Dividingcells Dermis Figure 8.11B
Asexual reproduction (seen here in a hydra) Figure 8.11C
Development (Sea urchin ) Figure 8.0x