Chapter 11 - Meiosis

Question 1

Somatic cells

Answer 1

any cell in the body that is not a sex cell & does not contain chromosomes –> autosomes

Question 2

Germline cells

Answer 2

sex cells –> gametes

Question 3

Why is meiosis necessary?

Answer 3

meiosis is necessary to create the haploid cells with half the number of chromosomes as parent cells that will combine during fertilization to create a diploid cell

Question 4

Why is fertilization necessary?

Answer 4

fertilization is necessary to combine one female gamete with one male gamete to create a diploid zygote

Question 5

What is the benefit of sexual reproduction vs asexual reproduction?

Answer 5

sexual reproduction creates genetic diversity that is the driving force of evolution & natural selection, and is the basis of inherited differences

Question 6

When & how does meiosis reduce ploidy?

Answer 6

meiosis reduces ploidy during anaphase I & anaphase II in which the homologous chromosomes & sister chromatids separate into individual cells

Question 7

Crossing over

Answer 7

occurs during prophase I –> alleles are exchanged between non-sister chromatids of paired homologous chromosomes by synapsis to create genetic diversity

Question 8

Independent assortment

Answer 8

occurs during anaphase I & II –> random assortment of homologous chromosomes or sister chromatids to opposite poles to form new haploid nuclei
-combines alleles of non-homologous chromosomes

Question 9

Random joining

Answer 9

occurs during fertilization –> the chance union (randomness) of male & female gametes during fertilization
-any female egg can combine with any male sperm

Question 10

Aneuploidy

Answer 10

the condition of having an abnormal number of chromosomes in a haploid set

Question 11

Non-disjunction

Answer 11

chromosomes fail to separate during the anaphase I or II stage of meiosis –> creates aneuploids
-trisomy 21 –> Down syndrome
-monosomy –> Turner syndrome