(Biol 211) Chap. 12 - The Cell Cycle

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procreate:

Back 1

reproduce

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cell division:

Back 2

reproduction of cells

- unicellular organisms:divides & forms duplicate offspring (reproduces an entire organims)

- on a larger scale: produce progeny from some multicellular organisms

- enables sexually reproducing from a single cell -- fertilized egg (zygote)

- continues function in renewal & repair, replacing cells that die from normal wear & tear or accidents.

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the functions of cell division:

Back 3

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cell cycle:

Back 4

the life of a cell from the time it is first formed from a dividing parent cell until its own division into two cells.

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what is most remarkable of cell division?

Back 5

the fidelity with which the DNA is passed along from one generation of cells to the next.

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genome:

Back 6

a cell's endowment of DNA, its genetic information.

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chromosomes:

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structure carrying genetic material, found in the nucleus of eukaryotic cells. Each one consists of one very long DNA molecules and associated proteins.

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somatic cells:

Back 8

- all body cells except the reproductive cells.

- contain 46 chromosomes made up of two sets of 23, one set inherited form each parent.

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Gametes:

Back 9

- reproductive cells

- sperm and eggs

- have 1/2 as many chromosomes as somatic cells. (contain 23 chromosomes)

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Chromatin:

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- complex of DNA & associated protein molecules

- this is what chromosomes are made out of.

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sister chromatids:

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containing an identical DNA molecule, are initially attached all along their lengths by adhesive protein complexes called cohesins.

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Centromere:

Back 12

a specialized region where the two chromatids are most closely attached.

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Gametes:

Back 13

- reproductive cells

- sperm and eggs

- have 1/2 as many chromosomes as somatic cells. (contain 23 chromosomes)

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Chromatin:

Back 14

- complex of DNA & associated protein molecules

- this is what chromosomes are made out of.

Front 15

sister chromatids:

Back 15

containing an identical DNA molecule, are initially attached all along their lengths by adhesive protein complexes called cohesins.

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Centromere:

Back 16

a specialized region where the two chromatids are most closely attached.

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Back 17

1. sister chromatids
2. chromosome
3. centromere
4. arm
5. chromatin

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Mitosis:

Back 18

the division of the nucleus

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cytokinesis:

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the division of the cytoplasm

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what happens to the chromosome # as we follow the human life cycle through the generations?

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you inherited 46 chromosomes, one set of 23 from each parent. they were combined in the nucleus of a single cell when a sperm from father united with egg from mother forming a fertilized egg (zygote).

Mitosis & cytokinesis produced the 200 trillion somatic cells that now make up your body. the same process continues to generate new cells to replace dead and damaged ones.

you produce gametes --eggs or sperm by meiosis, which yields nonidentical daughter cells that have only one set of chromosomes,.

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Meiosis:

Back 21

a variation of cell division which yields nonidential daughter cells that have only one set of chromosomes, thyus 1/2 as many chromosomes as the parent cell.

- occurs only in gonads (ovaries/ testes)

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Chromosome duplication and distribution during cell division.

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Mitotic (M) phase:

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includes both mitosis and cytokinesis.

- usually the shortest part of the cell cycle.

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Interphase:

Back 24

- much longer stage of the cell cycle.

- often accounts for about 90% of the cycle.

- cells grows & copies its chromosomes in preparation for cell division.

- can be divided into subphases:
G1 phase
S phase
G2 phase
(cells grows by producing proteins & cytoplasmic organelles. )

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which phase do chromosomes duplicate?

Back 25

S phase

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what happens in the G1 phase?

Back 26

cell grows

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what happens in the S phase?

Back 27

cell continues to grow as it copies its chromosomes.

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what happens in the G2 phase?

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cell grows more as it completes preparations for cell division.

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what happens during the M phase?

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cell divides.

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Mitosis is broken down into what stages?

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- prophase
- prometaphase
- metaphase
- anaphase
- telophase.

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the cell cycle:

Back 31

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The Mitotic Division of an Animal Cell:

Back 32

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Mitotic Spindle:

Back 33

- many of the events of mitosis are dependent.

- begins to form in the cytoplasm during prophase.

- consists of fibers made of microtubles and associated proteins.

- while they assemble, the other microtubles of the cytoskeleton partially disassemble (Prob. providing the material used to construct the spindle).

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Where does the assembly of spindle microtubules start at?

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at the centrosome

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Centrosome:

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a subcellular reagion containing material that functions throughout the cell cycle to organize the cell's microtubles

aka: microtubule-organizing center.

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Aster:

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a radial array of short microtubules extends from each centrosome.

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Kinetochore:

Back 37

- a structure of proteins associated w/ specific sections of chromosomal DNA @ the centromere.

- Face opposie directions in teh two sister chromatids of a replicated chromosome.

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metaphase plate:

Back 38

- the imaginary plane located between the spindle's two poles.

- where the centromeres of all the duplicated chromosomes are at metaphase.