BIOB11H3 Chapter Notes - Chapter 14: Metaphase, Robin Holliday, Genetic Recombination

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ceruleanweasel185

17 Mar 2012

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Meiosis (greek-reduction): formation of production of haploid phase in life cycle, fertilization ensures diploid phase. Diploid g2 cells contain pairs of homologous x-some, each containing 2 x-tids. During meiosis, 4 x-tids of a pair of replicated homologous x-somes are distributed among 4 daughter nuclei incorporates 2 division w/i intervening round of dna replication. In 2nd meiotic division, 2 x-tids of each x-some are separated from 1 another (anaphase ii) Meiotic division occurs after fertilization to produce haploid spores: sporic or intermediate meiosis: plants and some algae meiotic division take place at stage unrelated to gamete formation of fertilization. Sporophyte: diploid zygote undergoes mitotis and develops into this. Gametophyte: sporophyte produces spores that germinate to haploid gametophyte. S phase: several times longer than premitotic s phase. Prophase: prophases of 1st meiotic division lengthened in extraordinary fashion. 1st stage is leptotene, x-some visible in light microscope. 2nd stage is zygotene marked by visible association of homologues w/ one another.

Related Questions

Determine whether the following applies to mitosis, meiosis, orboth; also identify the specific stage of cell division thatapplies (e.g. mitosis prophase, meiosis anaphase II, etc)

1) chromosomes pairs line up across the center of the cell

2) sister chromatids seperate

3) spindle fibers separate homologous chromosomes

4) 4 haploid daughter cells are produced

5) a cell 1st undergoes DNA replication

6) chromosomes line up single file across the middle of thecell

7) sister chromatids separate from each other

8) 2 haploid daughter cells form

9) the nuclear membrane re forms

10) spindle fibers attach to pairs of homologous chromosomes

11) the nuclear membrane begins to dissolve

12) centrosomes duplicate

13) synapsis and crossing over occurs

14) 2 diploid daughter cells form

turquoiseporpoise808

During the cell cycle, separation of the chromosomes takes place during which stage?

a. S

b. M

c. G0

d. G1

e. G2

The homologous chromosomes are separated from one another during

a. first division of meiosis

b. S phase

c. prophase

d. mitosis

e. second division of meiosis

blushwombat537

1) A key part of meiosis is crossing over. Crossing over happens during prophase 1 and it does not occur again throughout the cell. Homologous recombination is another factor which is essential to the cell. My question is how are crossing over and homologous recombination similar and different in regards to their functions? They sound like the same thing but I think I might be confusing myself. In addition, why is crossing over only happening once if meiosis has two divisions? Thank you in advance.

2) To ensure the cell cycle proceed without mistakes there are checkpoints, one of which includes the recombination checkpoint. Recombination in meiosis is initiated if there is a double-stranded break in the DNA. My question is, what would happen to the cell if it fails to initiate recombination and proceeds
through meiotic division I and meiotic division II?â

BIOB11H3 Chapter Notes - Chapter 14: Metaphase, Robin Holliday, Genetic Recombination

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