Genetics Exam 1 Flashcards
1
Q
mRNA is:
A
A molecule that carries the genetic information from DNA and is used as a template for protein synthesis
2
Q
The sequence of one strand of DNA is 5’ -GCTTTAG- 3’ The sequence of the complementary strand would be:
A
5’-CTAAAGC-3’
3
Q
A ___________ is defined as any difference in DNA, no matter how it is detected, whose pattern of transmission from generation to generation can be tracked
A
Genetic marker
4
Q
DNA polymorphism is very common in the human genome
A
True
5
Q
What does “true breeding” means in Mendelian genetics?
A
The individual is a homozygote
6
Q
In a monohybrid cross of pea plants with round and wrinkled seeds, what is the genotypic ratio in the F2 generation? (please only put in genotypes and the ratio)
A
WW:Ww:ww = 1:2:1
7
Q
In a monohybrid cross of pea plants with round and wrinkled seeds what is the phenotypic ratio in the F2 generation? (please only put in phenotypes and the ratio)
A
Round: Wrinkle = 3:1
8
Q
The centromeres of sister chromatids uncouple and chromatids separate in which meiotic phase?
A
Anaphase II
9
Q
The process of cell division that ensures that each of the two daughter cells receives a complement of chromosomes identical with the complement of the parent cell is known as:
A
Mitosis
10
Q
We learned about using Chi-square test to measure goodness-of-fit. Which of the statements is False about the result of a chi-square test?
A
It tells us how likely we will get a certain outcome in an experiment that follows binomial distribution
11
Q
The process of cell division that ensures that each of the two daughter cells receives a complement of chromosomes NOT identical with the complement of the parent cell is known as:
A
Meiosis
12
Q
tRNA is:
A
A molecule that incorporates a specific amino acid into the growing protein when it recognizes a specific group of 3 bases
13
Q
What is genetics?
A
the study of inherited traits
14
Q
What is Genomics?
A
the study of all the genes in an organism
15
Q
What are the elements of heredity?
A
genes
16
Q
What are the 4 properties of the genetic material?
A
- can be replicated and transmitted
- control cellular processes and thues determibe phenotype
- can be sources of new variations
- contains info
17
Q
What do chromosomes contain and where are they located?
A
DNA and proteins, are located in nucleus
18
Q
What occurs to chromosomes during cell division?
A
Split into daughter cells
19
Q
Are the number of chromosomes constant in all the cells of a species?
A
Yes
20
Q
Is DNA or protein the genetic material?
A
DNA
21
Q
What is the difference between R-cells and S-cells?
A
R cells do not result in disease in mice while S cells do due to their protective carb capusle
22
Q
What is genetic transformation?
A
Genetic transformation is the change in DNA due to the introduction of new DNA that is later passed down
23
Q
What is a model organism?
A
An organism that is easily used for genetic analysis
24
Q
What is wild type?
A
the most common traits as it is naturally occurring in a particular species
25
What is mutant?
A form that is different from others of the same species
26
What is a mutation?
A change in DNA differing from the wild type DNA
27
What is forward mutagenisis screening?
Causing random mutations to occur through physical or chemical and then picking the desired phenotypes to do analysis on
28
What is a complete medium?
Contains various amino acids, vitamins, and other nutrients
29
What is a minimal medium?
Only the essential nutrients for growth
30
How are nutritional mutants identified via mediums?
Put suspected mutants into a complete medium and minimal medium to see if they can grow in both or only complete
31
How can you further identify mutants via specific mediums?
Put the mutants in specific minimal mediums with different nutrients to see which will allow it to grow
32
How do you know if they have the same gene affected?
complementation test
33
What is DNA?
deoxyribonucleic acid
34
If 2 mutants complements each other what is the phenotype
Wild type
35
If 2 mutants don't complements each other what is the phenotype
Mutant
36
What is RNA
ribonucleic acid, tRNA, mRNa, rRNA
37
What is protein
made up of amino acids and carries out cellular proceesses
38
Which has a double helix?
DNA
39
What is a double helix made up of?
2 polynucleotide chains in opposite directions
40
What is a nucleotide made up of?
phosphate, sugar, base
41
How many different bases does DNA have?
4
42
What are the base pairs?
A-T G-C
43
What is Chargaff’s rule?
A=T, G=C
A+C= T+G
44
Are DNA antiparallel?
Yes
45
What are the properties of DNA?
1. have complementary bases pairing
2. each strand has a direction based on group on the end
3. are antiparallel
4. double helix
46
What is mRNA?
transcribes the DNA into RNA which can then be used to translate into amino acid
47
What is tRNA?
transfer rna, adds chunks of amino acids to polypeptide chain
48
What is rRNA?
ribosomal rna, component of ribosome where protein synthesis take place
49
What is transcription?
From DNA to RNA
50
What is translation
From RNA to polypeptides
51
Can protein be translated back to RNA or transcribe back to DNA
No
52
Flow of biological info in a cell
DNA is transcribed into rRNA, mRNA, and tRNA which is the consolidated into ribosome. RIbosome is the translated into protein
53
What is the key features of the central dogma
Transcription results in info transfer from DNA to RNA
Translation results in information flow from RNA to protein.
Information does not flow from protein to either DNA or RNA.
54
What is alleles
alt form of genes
55
What is locus
A physical position of a gene on a chromosome
56
What are homologous chromosomes
The pair of chromosomes that comr from mom and dad
57
What is Genotype
the genetic makeup of a indiivdual
58
What is phenotype
the physical traits/ biochemical exp resulting from their genetic makeup
59
What can cause diseases
Blocks in metabolic pathways
60
What is alkaptonuria
black urine disease
61
What did ealy geneticists' believe
That there was one wildtype genotype and mutants were rare
62
What is polymorphic
Variances in alleles
63
What is the norm at genetic level
Variation
64
What is the most common type of human polymorphism
SNP single nucleotide polymorphism
65
What is a genetic marker?
A trackable difference in genes throughout generations
66
What is a DNA marker?
A trackable DNA difference in genes throughout generations
67
What is SNPs
Single sites where 2 or more nucleotide differs in a population with a frequency if more than 1%
68
How are SNPs detected
Through the use of restriction enzyme aka restruction fragment length polymorphism (RFLP)
OR
SNP chips
69
What are restriction enzymes
They are enzymes that cut DNA at a certain sequence of DNA and are isolated from bacteria
70
What are SNP chips
SNP use an DNA array to detect multiple SNPs
71
What are tandem repeat polymorphism
They are when 2 or more bases repeat
72
What is a simple sequence repeat (SSR) (3x)
aka microsatellite loci
abundant in the genome of eukaryotes
highly polymorphic
73
What are CNVs (Copy-number variations)
larger tandem repeats (akb to 1Mb)
can be detected by DNA array
74
What are the applications of DNA markers
1. localization of genetic risk factor
2. dna typing
75
What is an example of DNA typing
fingerprinting
76
How does DNA typing work?
There are 13 highly polymorphic gentic loci (SSR) --> other than identical twins, 2 inidivduals having the exact smae SSR loci is highly unlikely
77
What is a wild-type in the lab
A convenient refrence strain of a species
78
What is dominant
When you only need one of the allele for the phenotype to show
79
What is recessive
When you need both alleles for the phenotype to show
80
What is the molecular basis of wrinkled seed mutation
SBEI (starch branching enzyme gene)
Wildtype (round) is dominant
mutant (wrinkled) has an insertion of DNA into the SBEI gene that disrupts the shape
81
What is outcrossing
When you breed a plant with another plant that has a differing trait
82
What is hybird
the result of breeding a plant with another differing plant
83
What is a true breed strain
is when a plant self pollinates and only produces progeny like itself
84
What is a monohybrid cross
A cross of 2 true breeding strains with only 1 differing trait
85
What is the F1 result of a monohybrid cross
hetreozygote progeny
86
What is the result of F2 from a self fertilizing of F1 (progeny of monohybrid)
3:1 phenotype but 1:2:1 genotype
87
What are the key features of single gene inheritance (4x)
1. Genes come in pairs so each cell has 2 alleles
2. each pair of genes, alleles may be different or same
3. each gamete contains only 1 allele
4. union of male and female gametes is randome and result in allele pairs
88
What is testcross
Crossing a heterozygous organism to one with homozygous recessive alleles
89
What is a backcross
Crossing a hybrid with one of its parents
90
What is reciprocal cross
2 different ways of crosses depednign on which phenotype is on which sex
91
What does a testcross result in
1:1 genotype and phenotype
92
What is mendel's first law
The principle of segregation
93
What is the principle of segregation
The law states paired alleles will separate in that each gamete will have an equal chance of either allele
94
What is the F1 result of a dihybrid cross of true breeding strain
Double heterozygote
95
What is the result of F2 with F1 self fertilizing (dihybrid cross of true breeding strain)
9:3:3:1 phenotype 1:2:1:2:4:2:1:2:1 genotype
96
What is Mendel's second law
The principle of independent assortment
97
What is the principle of independent assortment
Segregation of any single allele is independent of the separation of another allele
98
Autosomal dominant allele characteristics (4x)
1. not sex linked
2. affected offsrping have a 1 affected parent
3. affected parent could be mom or dad
4. half of individuals that are siblings with affected parent are affected
99
What does autosomal mean
Not sex linked
100
Autosomal recessive allele characteristic (5x)
1. not sex linked
2. affected individuals usually have unaffected offspring
3. most affect individual have unaffected parents
4. parents of affected individuals are often relatives
5. among siblings of affected individuals (about 25% are affected)
101
Challeges of human genetics before molecular era (4x)
1. disease causing alles are rare and occur in small %
2. many simple mendelian diseases are recessive
3. # of offspring are small in humans
4. cant conduct testcrosses, backcrosses, or experimental crosses
102
An example of Simple/not harmful mendelian trait
PTC bitterness
103
PTC bittnerss dominant or recessive
dominant
104
PTC variation
varies from 0.00amM to 10mM
can be influenced by gender, environment, and other genes
105
Are most human genetic variations bad
no
106
Most of human conditions are caused by combined effect of genes and environment
True
107
What is incomplete dominance
in a heterozygote the phenotype does not remseble eitehr allele but somewhere in between
108
What is the result of incomplete dominance yield for F2 of self fertilize F1 (monohybrid cross)
1:2:1 phenotype and genotype
109
What are multiple allele
1. genetic locus can take on multiple alleles
2. common in natural pop
3. polymorphic loci used in forensics
110
How do multiple alleles come about
1. by chance: mutations accumulate throughout time and spread through breeding
2. certain mechanisms favor large # of alleles (self incompatibility)
111
What is self incompatilibity
When the favor different alleles than the same alleles
112
What are blood type determined by?
Polysaccharide on the surface of the blood cell
113
Different genotypes make different types of polysaccharide
True
114
What is epistasis
Non independent assortment of genes
115
What is germ cell
Reproductive cells ie sperm or egg
116
What is somatic cells
Nonreproductive cells
117
How many chromosomes does somatic cells have
46 (diploid) fixed number
118
How many chromosomes does gamete cells have
23 (haploid)
119
What is mitosis
daughter cells are identical to parent
120
What is meiosis
daughter cells are different from parent
121
What is interphase
G1, S, G2
122
What is G1
preparing DNA for replication
123
What is S
DNA replication
124
What is G2
DNA damage repair
125
When does the amount of DNA doubles
G2
126
Entering Mitosis (5x)
1. DNA has been replicated
2. Centromeres have not
3. Each chromosome has 2 sister chromatids
4. Sister chromatids after replication, 2 associated units of org chromosome
5. 2 sister chromatid held by 1 centromere = 1 chromosome
127
What are sister chromatids
Connected by centromere is the replicated portion of allele
128
What are the 4 stages of mitosis
1. prophase
2. metaphase
3. anaphase
4. telophase
129
What is prophase
chromosome condense
130
What is metaphase
chromosome align on the metaphase plate (equator)
131
What is anaphase
Sister chromatids separate
132
What is telophase
daughter chromosomes arrive at poles and nuclear envelop forms
133
What are the challenges of meiosis (3x)
1. need to go from diploid to haploid
2. DNA replication occurs once
3. following 2 divisions (chromosome # havlved)
134
What are homologous chromosomes
cells other than gametes contain 2 sets of chromosomes, 1 from father and 1 from mother
135
What is prophase 1
chromosomes pairing and condensation; crossing over (recombinatiom)
136
What is metaphase 1
homologous chromosomes align
137
What is anaphase 1
homologous chromosomes separate
138
what is metaphase 2
chromosomes align
139
what is anaphase 2
sister chromatids separate
140
what is nonjuctions
errors during meiosis when chromosomes fail to separate during anaphase (1 or 2)
141
what is an example of sex linked inheritance
Drosophila (fruit flies) eye pigment
142
How can you tell if a gene is linked to sex
reciprocal crosses does not give same results
143
what occurs if a gene is x linked (3x)
1. het females transmit x linked to half of their offspring
2. males with recessive x linked allele would exhibit the trait
3. males transmit the allele to all daughters and non sons
144
characteristics of human x linked pedigree (2x)
1. for rare traits, affected individuals are usually male
2. affected males have normal non carrier sons but carrier daughters
145
what is elementary outcomes
possible outcomes of an experiment that can not be reduced any further
146
what is an event
a combo of elementary outcomes
147
what is probability
a value proportional to the likelihood an event occurs (between 0-1, and equals to 1 when all combined)
148
When does P(AB) = P(A) * P(B)
when A and B are independent
149
What is conditional probability
when the probability of an event affects the probability of another event
150
what is binomial distribution
2 different outcomes, each independent from the other
151
What is the testing goodness of fit
a test about how closely the observed results "fit" with expected results based on hypothesis (aka chi square test)
152
what is the chi-square test
(observed-expected)^2 / expected
153
What P values rejects the hypothesis
less than .05 or .01
154
What is linkage
when genes are transmitted together
155
What is recombination
an exchange event (crossover) between homologous chromosomes results in new combo of alleles be transmitted
156
What is the max frequency of recombination
less than 50%
157
What is trans configuration
when mutations are on separate alleles
158
What is cis configurations
when mutations are on the same chromosomes
159
Recombination frequency is the same whether the alleles are in cis or
in trans
True
160
1 map unit = 1 percent of recombination = 1 map distance (1
centimorgan, cM) = 2 percent of crossovers
True
161
Additional facts about recombination (2x)
1. results from physical exchange between chromosomes
2. take places during the four strand stage of meiosis
162
The greater the physical distances between two markers, the more
likely a crossover takes place between them
True
163
Crossover is much less frequent in some regions of the chromosome
True
164
What is heterochromatin
the region of chromosome with a dense, compact structure during interphase
165
What is euchromatin
the rest of chromosome, which is only visible after chromosome condensation during mitosis and meiosis
166
Where is heterochromatin located in more organism
near centromere, or small blocks near ends, or interspersed with euchromatin
167
challenges in mapping human genes (4x)
1. matings cannot be arranged
2. configurations of genes cannot be easily determined
3. progeny numbers are small
4. generation times are long
168
What are the 2 methods in mapping human genes
1. Inferring linkage in pedigrees
2. Association mapping
169
What is inferring linkage in pedigrees
determining whether a gene is linked with RFLP or SSRP marker using family pedigrees
170
What is association mapping
searching for evidence of associations between alleles of genes and alleles of markers
171
What is allele of genes
disease genes that contribute to a phenotype
172
What is allele of markers
SNPs
173
What are the complications of inferring linkage in pedigree (3x)
1. the configuration of genes and markers
2. incomplete penetrance
3. environmental factors
174
Inferring linkage in pedigree requires pedigree data from more than a few families
True
