Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT TPR Biology > Genetics and Evolution > Flashcards

Genetics and Evolution Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards AP® Biology flashcards Biology 101 flashcards
1
Q

Are gene products always proteins?

A

no, tRNA and rRNA genes and other small nuclear RNA genes do not encode polypeptides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Locus?

A

specific location where a gene is located on a specific chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Can all physical traits be mapped on a single locus?

A

no, some complex traits can be controlled by many different genes and can map on many loci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Is it possible for there to be more than two different alleles of a specific gene?

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is true of an individual that has two different alleles at a given locus?

A

there is a different allele on each of the two members of a homologous pair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Can a haploid organism like an adult fungus have recessive alleles?

A

no because there is only one copy of the gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Classical Dominance?

A

there are three genotypes (CC, Cc, cc) but only two phenotypes are expressed because whenever the dominant is present it will be expressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Incomplete Dominance?

A

phenotype is a blended mix of the alleles (red and white make pink flowers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many phenotypes are possible if red and white flowers display incomplete dominance?

A

3 (red, white, pink)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Codominance?

A

two alleles are both expressed but not blended (ABO blood)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the phenotype of an individual heterozygous for blood type A and B alleles?

A

AB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the phenotype of an individual heterozygous for blood type B and i alleles?

A

B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

If a woman heterozygous for type A blood marries a man who is heterozygous for type B blood, what are the possible genotypes of their children?

A

A (A,i)
B (B,i)
AB (A,B)
O (i,i)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The Rhesus factor (Rh) follows a _____ _____ pattern.

A

classically dominant

Rh positive = RR, Rr
Rh negative = rr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Pleiotropism?

A

altering of many different, seemingly unrelated aspects of the organism’s phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Polygenism?

A

complex traits that are influenced by many different genes (ex. height)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Penetrance?

A

likelihood that a person with a given genotype will express the expected phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Epistasis?

A

expression of alleles for one gene is dependent on a different gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

100 people are homozygous for an allele that is implicated in cancer, but only 20 develop cancer. What are potential explanations for why only some people express a gene if they have the same genotype?

A
  • the trait for cancer is probably polygenic
  • cancer development is also influenced by the environment, such as exposure to carcinogens, which complicates the penetrance of the gene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What pattern of expression will a recessive allele on the X chromosome display in males?

A

it will always be expressed because men only have one X chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Sex linked traits?

A

traits determined by genes on the X or Y chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What type of cell division produces haploid cells from diploid cells by reducing the number of copies of each chromosome for two to one?

A

meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where does meiosis occur in males? females?

What is the end result for both?

A

males- testes, haploid spermatozoa

females- ovaries, ova

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the specialized cells in males that undergo meiosis? females?

A

males- spermatogonia

females- oogonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What makes meiosis different than mitosis?

A

meiosis has two rounds of cell division

recombination occurs between homologous chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What happens in prophase 1 of meiosis? (longest phase)

A
  • chromosomes condense
  • nuclear envelope breaks down
  • synapsis- homologous chromosomes pair with each other, bring two copies of each gene on two different chromosomes close together (paired chromosomes are called bivalent or tetrad)
  • Crossing over or recombination- genes are cut and then re ligated with genes swapped (genetic variation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Does crossing over change the number of genes on a chromosome?

A

no if done error free, it is a one for one swap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Does recombination create combinations of alleles on a chromosome that are not found in the parent?

A

yes, it contains the same genes, but the alleles could be different and mixed up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What happens in Metaphase 1?

A
  • alignment along the metaphase plate occurs

- tetrads are aligned at the center (mitosis- sister chromatids are aligned at the center)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What happens in Anaphase 1?

A

homologous chromosomes separate and sister chromatids remain together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What happens in Telophase 1?

A
  • divides into two cells

- at this point, the cells are haploid (pair of sister chromatids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the purpose of the second set of meiosis?

A

to separate the sister chromatids so that each cell has a single set of unreplicated chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the difference between meiosis 2 and mitosis?

A

in meiosis 2 there is a haploid number of chromosomes

mitosis there is a diploid number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the result after Telophase 2?

A

4 haploid cells have been produced from a single diploid parent cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

When homologous chromosomes separate, do all paternal and maternal chromosomes stay together in the daughter cells?

A

no, they separate randomly to increase genetic variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Are the sister chromatids that separate during meiotic anaphase 2 identical in their DNA sequence?

A

no, they would be though if recombination had not occurred during prophase 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Which of the following occur in meiosis, but not mitosis?

  1. separation of sister chromatids on microtubules
  2. pairing of homologous chromosomes
  3. recombination between sister chromatids
A

just 2

  1. happens in both
  2. recombination occurs between homologous chromosomes, not sister chromatids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

If cells are blocked in meiotic metaphase 2 and prevented from moving on in meiosis, which one of the following will be prevented?

A. crossing over
B. separation of homologous chromosomes
C. separation of sister chromatids
D. breakdown of nuclear envelope

A

C

A. happens during prophase 1
B. occurs during anaphase 1
C. occurs in anaphase 2
D. occurs in prophase 1 or 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Nondisjunction?

A

failure of homologous chromosomes to separate during meiosis 1 and sister chromatids during meiosis 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

A gamete normally has how many copies of each chromosome?

A

one (haploid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Gametes resulting from nondisjunction will have how many copies of a given chromosome?

A

either 2 or none

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

How many copies of the chromosome will the zygote have if a nondisjunction gamete fuses with a normal gamete?

A

either 3 (trisomy) or 1 (monosomy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Turner Syndrome?

A

only one X chromosome and no Y, female features but underdeveloped ovaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

In an individual with down syndrome, are the defects in development caused by an absence of genetic info?

A

no, there is too much

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Mendel’s Law of Segregation?

A
  • the two alleles of an individual are separated and passed on to the next generation singly
  • ex. if a pea is heterozygous, Gg, its gametes will contain either G or g but never both
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

At what stage of meiosis are different alleles of a gene separated?

A

meiosis 1 when homologous chromosomes separate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Mendel’s Law of independent assortment?

A
  • alleles of one gene will separate into gametes independently of alleles for another gene
  • ex. shape gene and color genes do not influence each other
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

F1 generation?

A

progeny of a testcross

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

If the color gene and the shape gene are right next to each other on a chromosome, will they display independent assortment?

A

no, linkage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Rule of multiplication?

A

the probability of both of two independent events happening can be found by multiplying the odds of either event alone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Rule of addition?

A

the chance of either of two events happening (either A or B happens, not both)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

A man is homozygous for eye color, bb, is married to a woman who is heterozygous at the same gene: Bb. What re the chances that a child will have Bb genotype and be a boy?

A

50% chance of Bb
50% chance of boy

.5 * .5 = 25%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

If the color gene and the height gene display linkage, is it possible to predict the possible gametes of a TTgg individual? of a TtGg?

A

yes because it can only make Tg gametes

no, it is necessary to know which gametes assort together

54
Q

When genes are located on the same chromosome, they will display ____ and not _____ _____.

A

linkage

assort independently

55
Q

What is the exception to linkage?

A

meiotic recombination- can separate alleles that were located on the same chromosome

56
Q

If it is known that two genes are located on the same chromosome but during a cross they assort completely randomly, how can this be?

A

they can be on the same chromosome but far apart so recombination would occur

57
Q

The frequency of recombination between two genes on a chromosome is proportional to what?

A

the physical distance between the genes along the linear length of the DNA, the farther apart they are the more frequent they go through recombination

58
Q

Frequency of recombination formula?

A

number of recombinant phenotypes divided by total number of offspring

59
Q

If the recomb frequencies are 16% between height and color genes, 10% between height and flower size genes, and 26% between flower and color genes, what is the order of genes on the chromosome?

A

flower
height
color

60
Q

Hemizygous Genes?

A

individual has only one copy of the chromosome (ex. X linked traits in males)

61
Q

Mitochondrial traits are only inherited through the _____.

A

mother

62
Q

Mitochondrial traits are only inherited through the _____.Why?

A

mother

because males only contribute nuclear genes and females contribute nuclear genes and whatever else is in the cell

63
Q

Hemizygous Genes?

A

individual has only one copy of the chromosome in a diploid organism (ex. X linked traits in males)

64
Q

Genes encoded by the mitochondrial genome are usually given the prefix ____.

A

mt

65
Q

Sex linked traits?

A

traits determined by genes located on the X or Y chromosome

66
Q

Would it be possible for a father to pass a Y linked trait to a daughter?

A

no because females do not have a Y chromosome

67
Q

Can males be carriers of recessive Y linked traits without expressing them?

A

no because there is only one Y chromosome so if they carry it, they also express it

68
Q

When will a female express a X linked recessive trait?

A

only when she is homozygous with the gene on both of her X chromosomes

69
Q

Example of an X linked recessive trait?

A

hemophilia

70
Q

From what parent do males receive X linked recessive traits?

A

from their mother (males are more affected than females)

71
Q

Is the colorblindness allele recessive or dominant?

A

recessive, an allele that encodes an inactive protein is generally recessive, in colorblindness the pigment gene does not produce a functional protein

72
Q

X linked dominant traits, when will females display it? males?

A

females- needs one or two copies of the allele

males- if he inherited the affected allele from his mother

73
Q

Autosomal traits? dominant? recessive?

A
  • both males and females are affected the same
  • on the other 22 chromosomes, not sex related
  • dominant- need a single copy
  • recessive- need both copies
74
Q

Example of an X linked recessive trait?

A

hemophilia

can skip generations, affects males more

75
Q

X linked dominant traits, when will females display it? males?

A

females- needs one or two copies of the allele

males- if he inherited the affected allele from his mother

can not skip generations, affects males more, affected fathers have all affected daughters

76
Q

Autosomal traits? dominant? recessive?

A
  • both males and females are affected the same
  • on the other 22 chromosomes, not sex related
  • dominant- need a single copy, does not skip generations, affected parent passes all or half of offspring
  • recessive- need both copies, can skip generations
77
Q

Is recombination possible in males between X and Y chromosomes?

A

no

78
Q

Population genetics?

A

inheritance of traits in populations over time

population- members of a species that mate and reproduce with each other

79
Q

If a group of sea turtles lives most of the year dispersed over a large area of ocean without contact but congregate once a year to reproduce, is this group a population?

A

yes, they only need to reproduce to be considered a group

80
Q

Gene pool?

A

sum total of all genetic info in a population

81
Q

If there are 5,000 hippos in a population, out of which there are 100 homozygotes of an autosomal allele h and 400 heterozygotes, what is the frequency of the allele in the population?

A

5,000 hippos * 2 copies of the gene each = 10,000 copies

100 homozygotes * 2 copies each = 200 copies

400 heterozygotes * 1 copy each = 400 copies

200 + 400 = 600 copies

600/10,000 = .06

82
Q

If 20% of the population is heterozygous for an allele Q and 10% homozygous, what is the frequency of the allele?

A

50% of the gene * 20% heterozygotes = 10%

10% alleles + 10% homozygous = 20%

83
Q

Hardy Weinberg Law? conditions?

A

frequencies of alleles in the gene pool of a population will not change over time if these assumptions are true:

no mutation
no migration
no natural selection
random mating
population is large to prevent drift
84
Q

Hardy Weinberg equation?

A

p + q = 1

p = frequency of dominant allele
q = frequency of recessive allele
85
Q

Hardy Weinberg equation (proportion of genotypes)?

A

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

p^2 = frequency of GG
2pq = frequency of Gg
q^2 = frequency of gg
86
Q

If the frequency of the G allele is .25 in a population of 1,000 mice, determine the number individuals who are Gg heterozygotes?

A

.25 + q = 1
q = .75

2pq = 2(.25)(.75) = .375

.375 * 1000 = 375

87
Q

Hardy Weinberg equilibrium?

A
  • population reaches equilibrium after one generation
  • parent and F1 generation will not have the same frequncies
  • F1 and F2 generations will be the same
88
Q

Fitness in evolution?

A

how successful an animal is in passing on its alleles to future generations

89
Q

Fitness in evolution?

A

how successful an animal is in passing on its alleles to future generations, the more offspring, the more fitness

90
Q

If an allele of a gene causes in elderly polar bears after their reproductive years have passed, how will it affect the fitness of the bears carrying the allele?

A

it will not affect fitness because it does not affect their ability to pass on the alleles

91
Q

If a recessive allele causes sterility in homozygotes, how will it affect the fitness of heterozygotes?

A

it will not affect the fitness

92
Q

If a population of sea otters contains only one allele of a gene that protects against cold, can natural selection drive evolution of this trait? Can natural selection cause new alleles to appear in the population?

A

if there is only one allele, there is no variability that natural selection can act on, so allele frequencies cannot change

natural selection can only alter existing alleles, not create new ones

93
Q

What are the two sources of genetic variation in a population?

A 
new alleles (mutations)
new combinations of existing alleles (recombination)
94
Q

Do new alleles in a population generally confer greater or lesser fitness on an individual carrying them?

A

most changes are harmful

95
Q

If a mutation occurs in a muscle cell of an individual who then has many progeny, does this mutation increase genetic variation in the population?

A

no, mutation must occur in the germ line to introduce a new allele into the population, mutations in somatic cells cannot be passed to the new generation

96
Q

Does mitosis contribute to the genetic variation in a population?

A

no, mitosis can only copy an identical cell, it is not involved in creation of new combinations of alleles

97
Q

If a population of flowers loses the ability to reproduce sexually and reproduces only asexually, how will this affect natural selection in the population?

A

if they can only reproduce asexually, then they have lost the ability of meiosis to generate new combinations of alleles for natural selection to act on

98
Q

Plants that are pollinated by insects sometimes have physical features of the flower that prevent self pollination, what is the advantage of preventing self pollination?

A

self pollination reduces genetic diversity

99
Q

What is the only thing that can create new alleles?

A

mutations of the genome

100
Q

What are the 6 modes of natural selection?

A
  1. directional selection- remove one of the extremes and the average moves the other way, giraffes get taller as all short giraffes die for lack of food
  2. divergent selection- remove the average splitting the species in two, small deer survive because they can hide, big deer survive because they can fight, medium deer cannot do either and die
  3. stabilizing selection- both extremes die and the population moves toward the average, birds too large or too small cannot mate and die
  4. artificial selection- humans intervene controlling mating, pets and crops
  5. sexual selection- some animals attract more mates, some birds have bright plumage to mate
  6. kin selection- animals that live socially sacrifice themselves for someone else, female lion sacrifices herself to save her sister’s children
101
Q

What is the difference between a population and a species?

A

members of a species can mate and produce offspring, members of a population do

population is a subset of species

102
Q

Reproductive isolation two types?

A

keeping existing species separate

prezygotic
postzygotic

103
Q

Prezygotic?

A

barriers prevent formation of hybrid zygote such as:

ecological- river separating species
temporal- individuals mate at different times of the year
mechanical- chihuahuas cannot mate with great danes
behavioral- mating rituals
gametic- incompatible sperm-egg, dog and cat

104
Q

Postzygotic?

A

barriers prevent development of hybrid, horse and donkey (sterile)

105
Q

Speciation?

A

creation of a new species

106
Q

Cladogenesis?

A

one species diversifies and becomes one or two more species

107
Q

Anagenesis?

A

one species changes so much that if it were to go back in time it would not be able to reproduce with its ancestors

108
Q

Allopatric isolation?

A

type of cladogenesis, geographic isolation leads to reproductive isolation

109
Q

Sympatric speciation?

A

a species gives rise to a new species in the same geographical area, divergent selection

110
Q

Homologous structures?

A

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

111
Q

Analogous structures?

A

serve the same function in two different species, but not due to a common ancestor (ex. bacterial flagella and human sperm)

112
Q

Convergent evolution?

A

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

113
Q

Divergent evolution?

A

divergent selection causes cladogenesis

114
Q

Parallel evolution?

A

two species go through similar evolutionary changes due to similar selective pressures

115
Q

What was different about the atmosphere of young Earth as opposed to now?

A

lacked O2

it was a reducing environment- electron donors were prevalent, O2 is an electron acceptor and breaks organic bonds

116
Q

binomial classification?

A

each organism is given two names: genus and species

117
Q

Homo sapiens? genus, species?

A

genus- Homo

species- sapiens

118
Q

8 categories of taxonomy?

A 
Domain              Dumb
Kingdom            King
Phylum               Phillip
Class                  Came
Order                 Over
Family                From
Genus                Greece
Species              Sunday
119
Q

Protobionts?

A

microspheres
liposomes
coacervate

120
Q

All life evolved from _____.

A

Prokaryotes

121
Q

What was different about the atmosphere of young Earth as opposed to now?

A

lacked O2

122
Q

In the early world, simple organics, monomers could form _____.

A

spontaneously, with metal ions on rock acted as catalysts
(abiotic synthesis)
(polypeptides made this way- proteinoids)

123
Q

Microspheres?

A

proteinoids in water spontaneously form droplets

when lipids are added liposomes form

124
Q

Coacervate?

A

complex particle including polypeptides, nucleic acids, polysaccharides

125
Q

Protobionts?

A

microspheres
liposomes
coaceravate

126
Q

In primitive Euk, introns were spliced out by ____.

A

ribozymes

127
Q

A mechanism of heredity was first provided by ____. Why?

A

RNA

because of its self replicating catalyzing abilities

128
Q

What were protobionts lacking?

A

organized form of heredity

129
Q

What was the last step in the evolution of the earliest cells?

A

switch from RNA to DNA because it is more stable

130
Q

9:3:3:1 ratio indicates what?

A

independent assortment

131
Q

If a white bull and a red bull mate and they have offspring with a roan coat (there are individual red and white hairs that do not blend) what is this displaying?

A

codominance

MCAT TPR Biology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions