Midterm 1 Flashcards
1
Q
genetics is the branch of biology that deals with
A
heredity and variation
2
Q
genetics is used to analyze genes –
A
in vivo
3
Q
two plant breeders who paved the way for Mendel’s experiments
A
Thomas Knight and John Goss
4
Q
peas were good because
A
short generation time, numerous varieties available, ability to cross fertilize and self-fertilize
5
Q
Goss established: peas were a good genetic system with clear –
A
heritable traits
6
Q
Goss established: parental characteristics could disappear for a generation and then reappear which could only be explained if units of heredity were – in nature
A
particulate
7
Q
Mendel brought methods that were – to biology
A
standard in Physics
8
Q
Mendel’s contributions
A
limited the number of variables
quantitated resulta
model that can be tested
9
Q
visible characteristics
A
phenotype
10
Q
Mendel’s hybrids had - in F1
A
uniformity
11
Q
Mendel’s hybrids tended to – in F2
A
revert to parental phenotypes
12
Q
Mendel’s theory: heredity determinants are of a – nature
A
particulate
13
Q
Mendel’s theory: each adult pea has – determinants for each character
A
2
14
Q
Mendel’s theory: the – only have 1 determinant for each character
A
gametes
15
Q
Mendel’s theory: each determinant – into gametes
A
segregates equally
16
Q
Mendel’s theory: union of 2 gametes occurs – with regard to genetic determinants
A
randomly
17
Q
since egg and sperm were believed to contribute equally to offspring, – probably contained genetic material
A
chromosomes
18
Q
eukaryotic cells contained – which contained chromosomes
A
nuclei
19
Q
haploid
A
only one set of chromosomes, one copy of each gene
20
Q
all chromosomes come in pairs (except sex chromosomes)
A
diploid organisms
21
Q
diploid organisms - each homolog has the same number and order of genes though may have different –
A
alleles
22
Q
impossible to tell – from chromosome pairs
A
genome size
23
Q
each chromatid is
A
one DNA molecule
24
Q
an organized profile of an organism’s chromosome
A
karyotype
25
chromosomes are made up of
DNA and protein (chromatin)
26
DNA is packaged into --
nucleosomes
27
chromatin in M phase is --
always condensed
28
heterochromatin
condensed state of interphase chromatin
29
heterochromatin is rich in repeated sequences, transposable elements, and --
centromeric DNA
30
chromosomes duplicate during
S phase
31
chromosomes segregate during
M phase
32
replicated chromosomes remain connected at --
centromere
33
each chromosomes is -- before replication
one DNA molecule
34
spindle fibers attach to protein complexes called -- that assemble on the centromere
kinetochores
35
centromeres can vary in position
metacentric/acrocentric
36
nuclear division associated with somatic cell division
mitosis
37
mitotic cell division results in
2 identical daughter cells
38
c = concentration of DNA relative to gamete or --
of chromatids per chromosome pair
39
n = # of --
chromosomes in gamete
40
describes how DNA is segregated into gametes
meiosis
41
reductional division
meiosis I
42
meiosis I
homologous chromosomes separate
43
equational division
meiosis II
44
meiosis II -- separate
sister chromatids
45
gametes have -- alleles
one
46
law of segregation (1st law)
two alleles of a gene separate during gamete formation and end up in different gametes
47
changes in DNA sequence
mutants
48
in humans, presence of -- determines maleness
Y chromosomes (SRY gene)
49
-- is the default sex
female
50
SRY transcription factor activates gene responsible for --
testis development
51
genes on sex chromosomes -- involved in sex functions
are not necessarily
52
disease related on X chromosome is much more likely to be seen in
males
53
X-linked dominant traits would be observed more in males or females?
females
54
T/F: Y chromosome evolved from X chromosome
true
55
genes are named after
first mutant allele
56
a
recessive allele
57
a+
wild type allele dominant to mutant
58
A
dominant allele
59
A+
wild type allele recessive to mutant
60
1902: Sutton and Boveri :Chromosome Theory of Inheritance
genes are located on chromosomes
61
points against chromosome theory of inheritance :chromosomes disappear in --
interphase (break apart?)
62
points against chromosome theory of inheritance: cytologically difficult to prove homologs pair in meiosis
could be random pairing
63
points against chromosome theory of inheritance: if genes are linked on chromosomes assortment of genes should --
not be independent
64
in flies, sex is determined by --
of X chromosomes
65
phenotype is expressed only in one sex
sex-limited trait
66
in sex limited traits, -- possess genes, but only expressed in one sex
both sexes
67
sex determines whether an allele is dominant or recessive
sex influenced trait
68
sex influenced trait may affect the extent of --
expression
69
pattern baldness is an example of
sex influenced trait
70
humans: one of the X's is -- early in development in females
inactivated
71
human females randomly inactivates one of the X's are --
mosaics
72
down syndrome correlates with nondisjunction in mother
meiosis I (50% no crossing over)
73
meiosis arrested in -- for decades
prophase I
74
1st law: for each gene, a gamete will end up with either allele from -
the mother of the allele from the father
75
always assume wild type is
homozygous
76
proof of the chromosomes theory of inheritance came from what research
study of sex-linked genes in Drosophila
77
Why do we have 1:1:1:1: phenotypic ratio in the F2?
because F1 females are heterozygous and because the F1 males behave like a tester strain
78
in flies sex is determined by --
number of X chromosomes
79
T/F: most traits are affected by more than one gene and cannot be analyzed using simple Mendelian genetics
true
80
recessive traits appear in progeny of --
unaffected individuals
81
recessive traits frequently show up in -- matings (cousins)
consanguineous
82
for recessive traits: -- from two affected individuals are affected
all progeny
83
probability of independent event occurring together is the -- of the probabilities of the individual events
product
84
probability of either of two mutually exclusively event occurring is the -- of their individual probabilities
sum
85
affected individuals appear in every generation
dominant traits
86
for dominant traits: two affected parents may have --
unaffected progeny
87
mendelian ratios apply to -- genes (3:1 or 1:1)
autosomal
88
sex-linked genes obey Mendel's laws but do not --
give Mendelian ratios
89
each dihybrid plant produces 4 gamete types --
with equal frequency
90
Mendel's Second Law
segregation of alleles of two different genes are independent of one another
91
law of independent assortment is explained by genes being located on --
different chromosomes
92
In the first division of meiosis, alleles are segregated
Mendel's first law
93
the first division of meiosis also segregates chromosomes independently
Mendel's second law
94
one gene (two phenotypes)
3: 1 F2 phenotypic ratio
1: 1 test cross phenotypic ratio
95
two genes (four phenotypes)
9: 3:3:1 F2 phenotypic ratio
1: 1:1:1 test cross phenotypic ratio
96
null hypothesis
A and B are unlinked expect a 9:3:3:1 F2 phenotypic ratio or 1:1:1:1 test cross phenotypic ratio
97
degrees of freedom =
of independently variable classes
98
if p
reject null (reject independent assortment with differences by chance alone)
99
single trait determined by multiple genes
polygenic inheritance
100
hardening of the arteries
athersclerosis
101
both mitochondria and chloroplast contain -- though they rely on nuclear genes as well
small circular chromosomes
102
each cell contains many copies of the organelle, and each organelle contains many copies of the --
chromosome
103
cytoplasmic organelles are inherited through the --
mother
104
-- during prophase I leads to crossover gametes
chiasma
105
crossing over: homologous recombination that is catalyzed by a set of --
enzymes
106
1% recombination =
1 map unit
107
frequency of recombination is proportional to the genetic -- (based on the assumption that recombination is random)
distance
108
examine linkage of autosomal genes? for simplification, instead of crossing F1 progeny (where recombination could occur in either parent), F1 females are crossed to --
tester male
109
recombination frequency often differs between
males and females
110
drosophila is an extreme where there is no recombination in --
males
111
we can never measure more than -- between two genes even if they are further away than --
50 mu
112
genes on different chromosomes also give -- mu
50
113
two genes located on different chromosomes give -- recombinants
50%
114
if genes are on the -- some meiosis will have no recombination between genes
same chromosome
115
if all meiosis have one or two recombination events between A and B, then the map distance will equal to 50 and A and B are considered --
unlinked
116
genes located far away on same chromosome will have 50% recombinant gametes and appear
unlinked
117
if some meiosis do not have a recombination between A and B, then there will be more parentals than recombinants and A and B are said to be
linked
118
each gene has a place or -- on its chromosome
locus
119
mutation -- a gene and locus
marks
120
genes or segregating allele are called
markers
121
2 genes are linked
on the same chromosome
122
-- linkage group per chromosome pair
one
123
groups of linked genes are known as --
linkage groups
124
when similar alleles are on the same chromosome
cis
125
when alleles are on different chromosomes
trans
126
w+y+/wy
cis
127
w+y/wy+
trans
128
when markers are relatively far apart, the observed distance is usually -- than the sum of distances due to double crossovers
less
129
wild type alleles usually encode the -- functional protein
normal
130
mutant allele changes either --, splicing, or amino acid sequence of protein
expression
131
T/F: phenylketonuria is one of the most common genetic abnormalities in US
true
132
if one copy of the gene is sufficient for normal function, then most non-functional alleles are --
recessive
133
if one copy is not sufficient for normal function, the wild-type is said to be -- and the mutant allele is dominant
haploinsufficient
134
mutant allele is recessive
haplosufficient
135
mutant allele is dominant
haploinsufficient
136
ABO blood types exhibit
co-dominance and complete dominance
137
I gene encodes enzyme that adds -- to membrane proteins
sugars
138
i allele is
nonfunctional (no sugar)
139
F1 hybrids show the traits intermediate between two parents
incomplete dominance
140
phenotype usually reflects genotype
incomplete dominance
141
F1 hybrids show the traits of both parents
co-dominace
142
everything is -- when you get down to the level of DNA (when you make both mutant and wild-type)
co-dominant
143
any allele found -- frequency in the wild is considered "wild type" other alleles are "mutant"
> 1% (all bloods types are considered wild type)
144
3:1 or 1:2:1 ratio
1 gene with different alleles
145
2:1 ratio is usually
lethal allele
146
condition in which a single gene has more than one effect on an individual
pleiotropic effect
147
recessive - lethality (YY)
| dominant - coat color (Yy) and sickle cell and malaria
pleiotrophic effect
148
in -- organisms, mutations in essential genes are lethal
haploid
149
lethal under some conditions but can survive under other conditions
conditional mutants
150
most traits are the result of --
many biochemical step
151
production of wild-type phenotype when two recessive mutant alleles are brought together in the same cell
complementation analysis
152
different gene =
complement
153
two different alleles of same gene
do not complement
154
complementation of 2 genes with no intermediate phenotypes
9:7 ratio
155
"--" means they are in the -- complementation group
same
156
gene that acts first is -- (stands over) to the second gene
epistatic
157
mutations that reverse the effect of an original mutation resulting in wild-type phenotypes
suppressors
158
suppressors usually from -- a mutant
mutagenizing
159
different ratios are observed if suppressor has mutant phenotype by itself; can be observed if the two proteins interact to form a --
complex
160
interacting proteins (suppressor)
10:6
161
biochemical pathway (suppressor)
13:3
162
two mutations have a stronger effect when combined
synthetic lethality (9:6 ratio)
163
15:1 ratio (everything is wild type except for double mutant)
duplicated genes
164
mutations which either increase or decrease the expression of a gene
modifiers
165
modifiers are frequently found in -- proteins
regulatory
166
distinguish between multiple alleles and multiples genes by ratios of --
F2 phenotypes
167
1:1, 1:2:1 3:1
single gene, (might have) multiple alleles
168
1:1:1:1, 9:3:3:1 (or variation)
two genes, two alleles
169
need one good copy of each gene for expression of final phenotype
complementation (9:7)
170
recessive epistasis
9:3:4
171
dominant epistasis
12:3:1
172
-- has unique life cycle which makes complementation analysis simple and distinct from recombination
neurospora (bread mold)
173
yeast have -- haploid or diploid states
stable
174
2 cells combine: cytoplasm becomes one but their nuclei stay separate
heterokaryon
175
heterokaryon can't have recombination but can have --
complementation
176
-- immediately undergo meiosis
transient diploid
177
separate during anaphase II of meiosis
sister chromatids
178
contain identical nucleotide sequences prior to crossing over
sister chromatids
179
separate during anaphase of mitosis
sister chromatids
180
in a pair, one is of maternal origin, the other of paternal origin
homologous chromosomes
181
crossover between them contributes to genetic diversity
homologous chromosomes (nonsister chromatids)
182
separate during anaphase I of meiosis
homologous chromosomes
183
They all have some mutation in the same wing-development gene.
Each strain may have a --, but the same gene is mutated in all strains in a complementation group.
different mutation
184
To construct a mapping cross of linked genes, it is important that the genotypes of -- of the gametes produced by the heterozygote can be deduced by examining the phenotypes of the progeny, taking into consideration that the homozygote produced only recessive gametes.
all
185
T/F: Gametes and their genotypes can never be observed directly
true
