Genetics and Evolution

Question 1

What are chromosomes composed of

Answer 1

DNA and protein

Question 2

Griffith experiment

Answer 2

used two strains of S. pneumonie to show that there was a transforming factor.

Heat killed S + live R strains killed the mice, meaning that the cell extract of the dead S conferred virulence to the R strain.

Question 3

Avery, MacLeod, McCarty,

Answer 3

Destroyed DNA and saw that the virulence wasn’t conferred to R, showing that DNA is the molecule of inheritance.

Question 4

Hershey and Chase

Answer 4

used two phage cultures, one labeled with P and one labeled with S, to confirm what Avery, MacLeod, and McCarty found.

Question 5

gene

Answer 5

fundamental unit of inheritance

Question 6

homologous chromosomes

Answer 6

two nonidentical copies of a chromosome from a mother and a father

Question 7

alleles

Answer 7

different versions of a gene

Question 8

genotype/phenotype

Answer 8

DNA sequence a person carries/ the physical expression of genotype

Question 9

dominant/recessive

Answer 9

dominant - allele that is expressed no matter what other allele is
recessive - allele that is silent unless present in homozygous state

Question 10

What does meiosis do?

Answer 10

Reduces number of copies of each chromosome from two to one, producing gametes

males - occurs in testes with haploid spermatozoa

females - in ovaries it produces ova

Question 11

difference between meiosis and mitosis

Answer 11

meiosis has two rounds and recombination/crossing over occurs between homologous chromosomes

Question 12

synapsis

Answer 12

when homologous chromosomes pair with each other during prophase I

Question 13

synaptonemal complex

Answer 13

mediates synapsis

Question 14

metaphase I

Answer 14

tetrads are aligned at the center of the cell

Question 15

anaphase I

Answer 15

homologous chromosomes separate and sister chromatids remain together

Question 16

telophase I

Answer 16

cell divides into two haploid cells with a single set of chromosomes

Question 17

meiosis II vs mitosis

Answer 17

movement of chromosomes are identical

Question 18

nondisjunction

Answer 18

failure of chromosomes to separate correctly during meiosis, can cause trisomy or monosomy

Question 19

law of segregation

Answer 19

two alleles of an individual are separated and passed on to the next generation as singles

Question 20

law of independent assortment

Answer 20

alleles of one gene will separate into gametes independently of alleles for another gene

Question 21

incomplete dominance vs codominance

Answer 21

phenotype of heterozygote is a mix of both alleles vs the two alleles are both expressed but not blended (ex blood type)

Question 22

linkage

Answer 22

failure of genes to display independent assortment

genes located close together will probably not be independently inherited

Question 23

What does recombination do to allele assortment?

Answer 23

It produces new combinations of alleles not found in the parent

Question 24

mitochondrial traits

Answer 24

affected females have all affected offspring

Question 25

autosomal recessive vs autosomal dominant

Answer 25

recessive - can skip generations

dominant - doesn’t skip generations

Question 26

y linked

Answer 26

only affects males

Question 27

x linked recessive vs dominant

Answer 27

recessive - affects males more, affected female has all affected sons
dominant - rare, affected females have all affected daughters

Question 28

population meaning

Answer 28

members of a species that mate and reproduce with each other

Question 29

gene pool

Answer 29

sum total of all genetic info in a population

Question 30

Hardy Weinberg assumptions

Answer 30

no mutation, no migration, no natural selection, random mating, large population

not possible for a population to meet all these conditions

Question 31

hardy Weinberg formulas

Answer 31

p+q = 1

p^2 +2pq + q^2 = 1

Question 32

hardy Weinberg equilibrium

Answer 32

allele frequencies no longer change

Question 33

natural selection effects

Answer 33

differential reproduction of different phenotypes

Question 34

fitness

Answer 34

how many offspring an individual can have

Question 35

modes of natural selection

Answer 35

directional, divergent, stabilizing, artificial, sexual, kin

Question 36

reproductive isolation

Answer 36

keeps existing species separate, includes pre zygotic and post zygotic mechanisms

Question 37

homologous structures

Answer 37

shared by two different species as a result of a common ancestor

Question 38

analogous structures

Answer 38

serve same function in two different species

Question 39

convergent evolution

Answer 39

two different species come to possess many analogous structures due to similar selective pressures

Question 40

principal taxonomic categories

Answer 40

domain, kingdom,phylum, class, order, family, genus, species