1 Cells grow larger and reproduce 2 Development

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1. Cells grow larger and reproduce 2. Development of whole organism from single cell

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 DNA Genetic information is encoded in the sequence of bases G G A

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

THE PATH OF PROTEIN SYNTHESIS DNA 1 m. RNA nucleus amino acids 2 ribosome

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

• Chromosomes consist of a long DNA molecule with thousands of genes Chromatin

• Chromosomes consist of a long DNA molecule with thousands of genes Chromatin = DNA with associated proteins Genome = one complete set of chromosomes for an organism Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The large, complex chromosomes of eukaryotes duplicate with each cell division • A eukaryotic

The large, complex chromosomes of eukaryotes duplicate with each cell division • A eukaryotic cell has many more genes than a prokaryotic cell Figure 8. 4 A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

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

a DNA in uncondensed form

a DNA in uncondensed form

a DNA chromatin DNA replication. . . duplicated chromosome cell …has this effect at

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

• When chromosomes are duplicated, sister chromatids are produced Sister chromatids Centromere telomere

• When chromosomes are duplicated, sister chromatids are produced Sister chromatids Centromere telomere Figure 8. 4 B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Human bands Figure 8. 19 x 1 Copyright © 2003 Pearson Education,

• Human bands Figure 8. 19 x 1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Human karyotype Figure 8. 19 x 2 Copyright © 2003 Pearson Education,

• Human karyotype Figure 8. 19 x 2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• When the cell divides, the sister chromatids separate Chromosome duplication – Two

• When the cell divides, the sister chromatids separate Chromosome duplication – Two daughter cells are produced – Each has a complete and identical set of chromosomes Sister chromatids Centromere Chromosome distribution to daughter cells Figure 8. 4 C Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

cell nucleus DNA 1. REPLICATION DNA • Eukaryotic cell division consists of two stages:

cell nucleus DNA 1. REPLICATION DNA • Eukaryotic cell division consists of two stages: – Mitosis – Cytokinesis 2. MITOSIS DNA 3. CYTOKINESIS DNA

DNA Mitotic Phase (M) DNA DNA Interphase esis s si ito M G 2

DNA Mitotic Phase (M) DNA DNA Interphase esis s si ito M G 2 Cytokin DNA Cell growth preparation for division Interphase G 1 Cell growth S DNA replication DNA Interphase DNA

INTERPHASE PROPHASE Centrosomes (with centriole pairs) Early mitotic spindle Centrosome Chromatin Nucleolus Nuclear envelope

INTERPHASE PROPHASE Centrosomes (with centriole pairs) Early mitotic spindle Centrosome Chromatin Nucleolus Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Figure 8. 6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fragments of nuclear envelope Centrosome Kinetochore Spindle microtubules

METAPHASE ANAPHASE Cleavage furrow Metaphase plate Spindle TELOPHASE AND CYTOKINESIS Daughter chromosomes Figure 8.

METAPHASE ANAPHASE Cleavage furrow Metaphase plate Spindle TELOPHASE AND CYTOKINESIS Daughter chromosomes Figure 8. 6 (continued) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Nuclear envelope forming Nucleolus forming

• Mitotic spindle Figure 8. 6 x 2 Copyright © 2003 Pearson Education,

• Mitotic spindle Figure 8. 6 x 2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Cytokinesis differs for plant and animal cells • In animals, cytokinesis occurs by cleavage

Cytokinesis differs for plant and animal cells • In animals, cytokinesis occurs by cleavage – which pinches the cell apart Cleavage furrow Figure 8. 7 A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Contracting ring of microfilaments Daughter cells

• In plants, vesicles build a new cell plate Cell plate forming Wall

• In plants, vesicles build a new cell plate Cell plate forming Wall of parent cell Cell wall Figure 8. 7 B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Vesicles containing cell wall material Daughter nucleus New cell wall Cell plate Daughter cells

• Binary fission - example: E. coli dividing Figure 8. 3 x Copyright

• Binary fission - example: E. coli dividing Figure 8. 3 x Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

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.

Review of functions of mitosis: • Mitotic cell division functions in: – Growth (ex. onion root) Figure 8. 11 A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Cell replacement (ex. skin) Dead cells Epidermis, the outer layer of the

• Cell replacement (ex. skin) Dead cells Epidermis, the outer layer of the skin Dividing cells Dermis Figure 8. 11 B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Asexual reproduction (seen here in a hydra) Figure 8. 11 C Copyright

• Asexual reproduction (seen here in a hydra) Figure 8. 11 C Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Development (Sea urchin ) Figure 8. 0 x Copyright © 2003 Pearson

• Development (Sea urchin ) Figure 8. 0 x Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings