Lecture 20-21: Meiosis

Question 1

what is heredity?

Answer 1

the transmission of traits from one generation to the other

Question 2

why is there variation in populations?

Answer 2

due to the different combinations of alleles that get passed on

Question 3

_______ are the unit of heredity

Answer 3

genes

Question 4

where are protein-coding genes transcribed?

Answer 4

mRNA

Question 5

where are non-protein coding genes transcribed?

Answer 5

rRNA, tRNA, miRNA, etc. (“housekeeping genes”)

Question 6

the gene’s specific location on a chromosome is its ______

Answer 6

locus

Question 7

what are the two main cell types?

Answer 7

somatic and gametes

Question 8

two types of reproduction:

Answer 8

asexual
sexual

Question 9

explain asexual reproduction:

Answer 9

parent is a single individual, all daughter cells are made by mitosis and genetically identical

Question 10

pros and cons to asexual reproduction:

Answer 10

pro: fast!
con: less genetic diversity, makes it hard to adapt to changing environments

Question 11

explain sexual reproduction:

Answer 11

two parents, gametes are made by meiosis, they are genetically similar but not identical!

Question 12

pros and cons of sexual reproduction:

Answer 12

pro: more genetic diversity, can adapt
con: energetically expensive, slow

Question 13

what is the “life cycle”

Answer 13

from an organisms own conception to the production of its own offspring

Question 14

how many chromosomes do humans have in somatic cells?

Answer 14

46

Question 15

are human somatic cells haploid or diploid?

Answer 15

diploid, one chromosome from each parent (2n = 46)

Question 16

are gametes haploid or diploid?

Answer 16

haploid (n=23)

Question 17

______ merges two haploid gametes to form a diploid zygote (2n=46)

Answer 17

fertilization

Question 18

what is ploidy?

Answer 18

number of sets of chromosomes in a cell

Question 19

what is homologous recombination?

Answer 19

when meiosis swaps bits of homologous chromosomes together to combine them

Question 20

how do we count chromosomes?

Answer 20

the number of centromeres (the narrow part visible by a microscope)

Question 21

what is the main purpose of meiosis?

Answer 21

reduces diploid cells to haploid cells

Question 22

what does meiosis I do?

Answer 22

separates homologous chromosomes

Question 23

what does meiosis II do?

Answer 23

separates sister chromatids