11. Meiosis

Question 1

what is meiosis?

Answer 1

sexual reproduction - duplication of chromosomes

Question 2

how many daughter cells come out from meiosis?

Answer 2

four - there are two cell divisions (meiosis I and meiosis II)

Question 3

are the daughter cells from meiosis diploid or haploid?

Answer 3

they are haploid! half as many chromosomes as the parent cell

Question 4

define a diploid cell

Answer 4

two sets of chromosomes in teh gametes. one derived from the ovum (female) and one from the spermatoazoon (male)

Question 5

define a haploid cell

Answer 5

a single set of unpaired chromosomes. theres only one set

Question 6

what is the name of the protein that holds the sister chromotids together in prophase 1?

Answer 6

cohesins

Question 7

does recombination and crossing over occur at

a. prometaphase 1
b. prophase 1
c. anaphase 1
d. prophase 2

Answer 7

b. prophase 1!!!

Question 8

when does chiasmata occur - a consequence of crossing over

hint: what process is it?

Answer 8

during metaphase 1 - homologus pairs of crhomosomes line up and are held together by chiasma

Question 9

when does segregation occur?

Answer 9

during anaphase 1 - the two members of the pairs of homologous chromosomes are seperated

Question 10

define aneuploidy

Answer 10

when meiosis goes wrong - an abnormal amount of chromosomes

Question 11

name four features of a homologous chromosome?

Answer 11

always same size and shape

same genes at the same loci

each gene can have different alleles

always as a pair

Question 13

define independant assortment

Answer 13

random mixing of paternal and maternal chromatids in gametes

Question 14

difine non-disjunction and how it happens

Answer 14

its an error in meiosis, when chromosomes dont move to different poles during anaphase 1 or 2