Biology Questions and Answers

(Greg DeLong) #1

Biology Questions and Answers


provides recombination of alleles (of
different genes) linked in the samechromosome during cell divison by
meiosis.



  1. What are the “chiasms” of
    homologous chromosomes
    seen in prophase I?


Chiasmsin the form of X. are intersections of two tracts


The chiasms seen in prophase I are


chromosome arms of their homologous. In fact whenarms crossing over same (^)
chiasms are seen under the microscope
chromatidschromosomal se are exchanginggments with ot (^) her
chromatids of its homologous.



  1. Is there interphase again
    between meiosis I and
    meiosis II?


There is no interphase noduplication between the divisions ofr DNA (^)
meiosis. Only a sdiakinesis occurs.hort interval called



  1. What are the periods of
    the second meiotic division?


Meiosis II is divided into prophase metaphase II, anaphase II and telofaseII, (^)
II.



  1. What are the respective
    functions of the separation of
    homologous chromosomes
    and of the separation of
    identical chromatids in
    meiosis?
    The separation of homologous
    chromosomes ifunctions: to reduce to a half the totaln meiosis I has two main
    number of chromosomes, generating
    haploid process, andaughter cells at the d to make possible geneticend of the


recombinatioaleatory, i.e., each pair of daughter cellsn since the separation is (^)
can be different from the other pair
relating chrpaternal and maternal oomosomal combirigins. (Annation frd ifom
crossing over is considered each of the
four resultinthe others.)g cells can be different from
The separation meiosis II has thof identicale same function it chromatids has in
in mitosis: to separate the
chromosomes alrdaughter cells. eady duplicated to the



  1. During which meiosis
    division does ploidy reduction
    occur? Does ploidy reduction
    occur in mitosis?


In the cell division breduction occurs in meiosisy meiosis ploidy II. Initially, (^)
taking as example a 2n somatic cell,
ploidy increases to 4DNA) during interphase. Dn (duplicationuring meiosis of (^)
I, since homologous chromosomes are
separated, number) and then during meiosis IIploidy falls to 2n (the original
ploidy finally falls to n in the resulting
daughter cells.
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