Meiosis

Question 1

what are homologous chromosomes?

Answer 1

chromosomes that are the same in length, centromere position, and gene location

they vary in alleles

Question 2

what is an allele?

Answer 2

a variation of a gene

Question 3

what is a sister chromatid

Answer 3

a duplicated chromosome, it is an identical copy

Question 4

What is asexual reproduction

Answer 4

one parent produces genetically identical offspring by mitosis

Question 5

what is a clone

Answer 5

a group of genetically identical individuals from one parents

Question 6

What are gametes

Answer 6

sperm and egg

they are reproductive cells

Question 7

Meiosis

Answer 7

is a specialized form of cell division that produces haploid gametes

Question 8

What are germ cells

Answer 8

meiosis occurs in germ cells in the ovaries and testes

Question 9

what is fertilization

Answer 9

the union of gametes

Question 10

what is a locus

Answer 10

the position of a gene on a chromosome

Question 11

How many cell divisions does meiosis undergo?

Answer 11

2 consecutive cell divisions

creates four daughter cells rather than 2

Question 12

How do mitosis and meiosis compare in production of daughter cells

Answer 12

meiosis creates genetically different daughter cells

Question 13

what happens during meiosis 1

Answer 13

the homologous chromosome pairs are separated into two separate cells

Question 14

what happens during meiosis 2

Answer 14

the sister chromatids are separated to produce 4 haploid cells

Question 15

what is chiasmata

Answer 15

the site of crossover between nonsister chromatids

Question 16

What happens in prophase 1

Answer 16

chromosomes condense

microtubule spindle forms

each chromosome consists of 2 sister chromatids attached at centromere

homologous chromosomes pair along their entire length

cross over occurs between non sister chromatids

Question 17

what happens in metaphase 1

Answer 17

homologous chromosomes align at the equator

chiasmata keep homologous pairs together

the kinetochores attach to homologues on either side

Question 18

what happens in anaphase 1

Answer 18

homologous pairs are pulled apart but sister chromatids do not separate

Question 19

telophase 1

Answer 19

nuclear envelope reforms around each daughter cells

results in 2 cells that have half the number of chromosomes of the original cell

sister chromatids are not identical due to crossover

Question 20

when are cohesions cleaved in meiosis

Answer 20

anaphase 1: along chromosome arms at the separation of homologs

anaphase 11: at the centromeres (separation of sister chromatids)

Question 21

does chromosome replication occur between meiosis phases

Answer 21

no

Question 22

what happens in meiosis 2

Answer 22

the same sequence, except microtubules attach to sister chromatids and they are pulled apart to create 4 haploid daughter cells

Question 23

What are the 4 distinct features of meiosis

Answer 23

Homologous pairing (synapsis) and crossing over of maternal and paternal homologues

Independent assortment of homologous chromosomes in metaphase 1

Sister chromatids remain attached in anaphase 1

DNA replication is suppressed between two meiotic divisions

Question 24

what is a reductional division?

Answer 24

meiosis 1 results in two haploid daughter cells

Question 25

What is equational division

Answer 25

Meiosis 2 results in 4 haploid daughter cells with unreplicated chromosomes

Question 26

what are the three mechanisms that result in genetic variation?

Answer 26

crossing over
independent assortment of chromosomes
random fertilization

Question 27

What is crossing over

Answer 27

homologous non-sister chromatids combine at corresponding dna sequences , during Prophase I

Question 28

what is independent assortment of chromosomes

Answer 28

homologous pairs of chromosomes orient randomly at Metaphase I

Question 29

What is random fertilization?

Answer 29

each individual can generate a variety of gametes and any sperm could fertilize an egg

Question 30

What are recombinant chromosomes?

Answer 30

chromosomes that result from crossing over and the combination of genes from each parent

homologous portions of non-sister chromatids trade places

Question 31

what is independent assortment?

Answer 31

homologous pairs orient randomly at metaphase I of Meiosis

each pair sorts maternal and paternal homologs into daughter cells independently of other pairs

number of combinations possible = 2^n

Question 32

What are germ cells

Answer 32

sex cells that are found in the ovaries and testes

Question 33

what are gametes

Answer 33

haploid cells that are produced from meiosis of germ cells

Question 34

what are somatic cells

Answer 34

cells that are for body functions, they do not undergo meiosis

Question 35

whats the difference between a diploid and a haploid cell

Answer 35

a diploid cell has a homologous pair (two of the same type)

a haploid cell only has one chromosome for each type

Question 36

Whats the difference between an autosome and a sex chromosome

Answer 36

autosomes are not related to sex determination while sex chromosomes are

Question 37

What’s the difference between a gene and an allele

Answer 37

a gene is a sequence that codes for a trait

an allele is a variation of that trait found at the same place on the chromosome

Question 38

what are all the mechanisms related to genetic variation

Answer 38

errors/ mutations in DNA rep

production of recombinant chromosomes

independent assortment of homologous chromosomes in meiosis 1

separation of sister chromatids

random fusion of gametes in fertilization

Question 39

what are recombinant chromosomes?

Answer 39

they are produced from crossing over which creates nonidentical sister chromatids (swapped corresponding DNA segments)

combined genes from each parent