Genetics Test Review #2 Flashcards
1
Q
Gregor Mendel
A
principles of heredity
2
Q
Schleiden and Schwann
A
cell theory
3
Q
Flemming
A
chromosomes
4
Q
Darwin
A
evolution
5
Q
Weismann
A
germ-plasm theory
6
Q
Sutton
A
genes located on chromosomes
7
Q
Morgan
A
mutant fruit flies, transmission genetics
8
Q
Genes are the fundamental unit of
A
heredity
9
Q
Genes come in multiple forms called
A
alleles (encode a specific trait)
10
Q
Genes confer
A
phenotypes
11
Q
Genetic information is carried in
A
DNA and RNA
12
Q
Genes are located on
A
chromosomes
13
Q
Central Dogma
A
DNA to RNA to Protein
14
Q
Mutations are
A
permanent changes
15
Q
Evolution is
A
genetic change (change in allele frequency through population of species)
16
Q
What is heredity?
A
the passing down of traits from one generation to another
17
Q
Different alleles for a particular gene occupy
A
the same locus on homologous chromosomes
18
Q
What is a locus?
A
a place on a chromosome where genetic information encoding a characteristic is located
19
Q
What is a genotype?
A
set of alleles possessed by an individual
20
Q
What is a phenotype?
A
the manifestation or appearance of a characteristic
21
Q
Monohybrid crosses revealed what?
A
the principle of segregation and the concept of dominance
22
Q
Heterozygotes produce offspring with a
A
1:2:1 genotypic ratio and 3:1 phenotypic ration
23
Q
Dihybrid Crosses revealed what?
A
the principle of independent assortment
24
Q
What is Independent Assortment?
A
gametes located on different chromosomes will sort independently
25
How are the principles of segregation and independent assortment related?
both refer to the separation of alleles in anaphase I of meiosis
26
How are the principles of segregation and independent assortment different?
principle of segregation says that these alleles separate; principle of independent assortment says that the separate independently of alleles at other loci
27
What is population genetics?
concerns the genetic composition of a population and how it changes over time
28
What are the five major causes of evolutionary change?
natural selection, mutation, gene flow, genetic drift, non-random mating
29
What is a gene pool?
the frequencies of genotypes and alleles in the population
30
How do you calculate genotypic frequencies?
number of individuals possessing the genotype divided by total number of individuals in sample
31
How do you calculate allelic frequencies?
number of copies of a particular allele present in a sample divided by total number of alleles
32
What is Hardy-Weinberg Equilibrium?
A population’s allele and genotype frequencies are constant, unless there is some type of evolutionary force acting on them
33
If allelic frequencies change,
then evolution is occuring
34
If allelic frequencies remain consistent over generations,
then equilibrium is reached, and evolution is not occurring
35
What is p?
the frequency of the dominant allele
36
What is q?
the frequency of the recessive allele
37
What is p^2?
the frequency of homozygous dominant individuals
38
What is 2pq?
the frequency of heterozygous individuals
39
What is q^2
the frequency of homozygous recessive individuals
40
What are the 5 model assumptions of Hardy-Weinberg Equilibrium?
no mutations must occur, no gene flow can occur, random mating must occur, the population must be large, no selection can occur
41
When a population is in Hardy-Weinberg equilibrium, the proportion of genotypes are determined by
the frequencies of alleles
42
What is genetic drift?
change in allele/genotype frequency by random chance
43
Genetic drift has a large effect on
small populations
44
What is positive assortative mating?
a tendency of like individuals to mate
45
What is negative assortative mating?
a tendency of unlike individuals to mate
46
Individuals may be homozygous by
decent or state
47
What is identical by descent?
when two copies of an allele are descended from the same copy in a common ancestor
48
What is identical in state?
when two copies of an allele are the same in structure and function, but are descended from two different copies in ancestors
49
What is inbreeding
the measure of probability that two alleles are identical by descent
50
Natural selection is favoring those
mutations that are accumulating over time
51
Mutations cause changes in
allelic and genotype frequencies in a population
52
Migration results in the
addition of genetic variants
53
The amount of change in allelic frequency due to migration depends on the
difference in allelic frequency and the extent of migration
54
Natural selection is more effective when
populations are large
55
What is stabilizing selection?
favors individuals with a trait near the mean of the population
56
What is directional selection?
favors individuals at one end of the distribution of a trait
57
What is disruptive selection?
favoring individuals at either end of the distibution
58
Sex chromosomes are
heteromorphic
59
Male sex chromosomes differ from female sex chromosomes in
size and shape
60
X and Y chromosomes are homologous only at
pseudoautosomal regions
61
X and Y chromosomes pair during
meiosis
62
Zygote is
diploid
63
Gametes are
haploid
64
Meiosis produces
haploid gametes
65
Fertilization produces a
diploid zygote
66
What are sex cells
sperm and egg
67
Gamete production is produced through
meiosis
68
Gamete formation reduces genetic information by
half
69
What is the size difference in sperms and eggs
sperms are smaller than eggs
70
What is hermaphroditism?
both sexes in the same organism
71
What is monoecious?
both male and female reproductive structures in the same organism
72
What is dioecious?
either male or female reproductive structures in one organism
73
What are autosomes?
any chromosome that is not a sex chromosome
74
What is the XX-XO system (Ex. grasshoppers)?
XX (homogametic) - female
XO (heterogametic) - male
75
What is the XX-XY system (Ex. mammals)?
XX (homogametic) - female
XY (heterogametic) - male
76
What is the ZZ-ZW system (Ex. butterflies)
ZZ - male
ZW - female
77
What is the haplodiploidy system (Ex.bees)?
haploid set - male
diploid set - female
78
What is a genic sex-determination system?
sex determination is governed by separate genes or alleles present on specific locus of the chromosomes
79
What is the Genic Balance Theory (Calvin Blackman)?
in drosophila, sex is determined by the genic balance between X chromosomes and autosome genomes (sets)
80
Where is extranuclear DNA found?
in mitochondria and chloroplasts
81
What do sperm rarely carry?
mitochondria and chloroplasts
82
What is maternal inheritance?
when extranuclear DNA is passed to the next generation only by the female parent
83
What is environmental sex-determination?
environmental factors influence the sex of an organism (Ex. limpets, ferns, sea turtle eggs)
84
Gametophytes can be
bisexual
85
What does the SRY gene on the Y chromosome do?
determines maleness
86
What is turner syndrome?
females with a single X chromosome in their cells (X0)
87
What is random X-inactivation (Ex. tortoiseshell cats)?
the random inactivation of one X chromosome in females
88
What is a mixed sex determination system?
interaction of both genetic and environmental factors
89
Wheat has a genome consisting of chromosomes from
three different species (einkorn wheat, wild grass, and emmer wheat)
90
What is a hexaploid?
6n = 42
91
What is chromosome morphology?
position of the centromere on the chromosome
92
What is condensation of chromosome?
look at diagram in PPT
93
Differentiate metacentric, sub-metacentric, acrocentric, and telocentric
on PPT
94
What is a karyotype?
the complete set of chromosomes possessed by an organism
95
What do chromosome rearrangements do?
alters the structure of chromosomes
96
What does aneuploidy do?
alters the number of chromosomes
97
What is polyploidy?
an organism that has more than two sets of chromosome (one or more complete sets are added)
98
Understand chromosome mutations.
on PPT (figure 8.3)
99
What is duplication?
a segment of the chromosome is duplicated
100
What is deletion?
a segment of the chromosome is deleted
101
What is inversion?
a segment of the chromosome is turned 180 degrees
102
What is translocation?
a segment of a chromosome moves from one chromosome to a non-homologous chromosome or to another pace on the same chromosome
103
Understand types of chromosome duplications.
on PPT
104
What is the effect of chromosome duplication?
the duplicated chromosome loops out during pairing in prophase I
105
Understand drosophila X-linked duplication.
on PPT
106
Understand consequences of gene duplication.
on PPT (figure 8.2)
107
When genes duplicate, they can
take on new functions
108
Unequal crossing over produces
duplications and deletions
109
Large deletions are
easily detected
110
What are some effects of deletions?
imbalances in gene product, expression of a normally recessive gene (pseudodominance), and haploinsufficiency
111
Formation of deletion loops during pairing of homologs in
prophase I
112
What is pseudodominance?
expression of a normally recessive mutation
113
When is pseudodominance produced?
when the dominant wild-type allele in a heterozygous individual is absent due to a deletion on one chromosome
114
What is haploinsufficiency (Ex. notch gene)?
when a single copy of a gene is not sufficient to produce the wild-type phenotype
115
Inversion depends on
the involvement of the centromere
116
Paracentric inversion
does not include centromeres
117
Pericentric inversion
includes centromeres
118
Chromosome 4 differs in humans and chimpanzees by a
pericentric inversion
119
Understand different types of translocation.
non reciprocal intrachromosomal translocation - movement of chromosomal segment from one location in the chromosome to another
non reciprocal interchromosomal translocation - movement of chromosomal segments between chromosomes
reciprocal interchromosomal translocation - chromosome segments are exchanged between two homologous chromosomes
120
What is Robertsonian translocation
the short arm of one acrocentric chromosome is exchanges with the long arm of another
121
What are causes of aneuploidy?
-deletion of centromere during mitosis and meiosis
-Robertsonian translocation
-nondisjunction during meiosis and mitosis
122
What is aneuploidy in Jimson weed?
-mutant capsules in Jimson weed result from
different trisomies
-each type of capsule is a phenotype that is trisomic for a different chromosome
123
What is autosomal aneuploids in humans?
down syndrome
124
What is trisomy 21?
down syndrome
125
What is primary down syndrome?
75% random nondisjunction in egg formation
126
What is familial down syndrome?
Robertsonian translocation between chromosomes 14 and 21
127
What is autopolyploidy?
from single species
128
What is allopolyploidy?
from two species
