Genetics Final Exam
With which of the following methods the CRISPR-Cas9 components can be delivered into cell?
-Direct ribonucleoprotein bombardment -Bombardement of a plasmid containing the CRISPR-Cas9
Correct statements
-During transcription, an RNA is transcribed in the 5'-to-3' direction -During transcription, the template strand is read in a 3'-to-5' direction
Incorrect statement
-During transcription, the template strand is read in a 5'-to-3' direction -During transcription, an RNA is transcribed in the 3'-to-5' direction
What entities are involved in regulating GMO crops in the US?
-Environmental Protection Agency -US Department of Agriculture -Food and Drug Adminstration
Which of the following will be not translated?
-Promoter -Enhancers -5' and 3' UTRs -introns
If you cross two heterozygous plants, what proportion of the offspring will also be heterozygous?
1/2
Amino acids bind to which part of the tRNA?
3' end
How many total histone proteins form a nucleosome
8
With which of the following methods the CRISPR-Cas9 components cannot be delivered into cell?
Agrobacterium-mediated transformation with the CRISPR-Cas9 components
Primers are synthesized where on the lagging strand?
At the beginning of every Okazaki fragment
During translation initiation in eukaryotes, how does the small ribosomal subunit with the initiation components bind to the mRNA?
By recognizing the 5' cap
Several of all-white cats are crossed and they produce the following types of progeny: 12/16 all-white, 3/16 black, and 1/16 gray. Based on the phenotypic ratios, what type of gene interaction seems to be going on?`
Dominant epistasis
A DDYY individual is crossed to a ddyy individual. Which of the following represent the recombinant gamete genotypes?
Dy and dY
If a regulatory protein that is a repressor binds to its regulatory region in the DNA, what will be the effect on gene expression?
It will inhibit transcription
If a regulatory protein that is an activator binds to its regulatory region in the DNA, what will it be the effect on gene expression?
It will stimulate transcription
The lac operon is an example of an inducible operon, which means it is normally "___" and can be turned "___" in response to an effector (inducer) binding to a __________ protein.
Off, on, regulatory
Phosphorylation and ubiquitination are common examples of:
Post-translational modifications
In the Avery, MacLeod and McCarty experiments, what conclusion would the scientists have drawn if only when the proteins of heat-killed S strain bacteria were destroyed the mice lived? Note: this is a hypothetical situation.
Protein is the genetic material
Which of the following phrases does NOT describe a function of the promoter
Signals where translation begins
Which of the following is NOT a characteristic of a eukaryotic cell?
Single circular chromosome
Which statement is not an assumption of the Hardy-Weinberg principle?
The allelic frequencies (p and q) are equal
Which class of RNA is correctly paired with its function?
Transfer RNA (tRNA): transports amino acids
Which entity is not involved in regulating GMO crops in the US?
US Department of Commerce
What is the most likely type of inheritance for this disease?
Y-linked
Genome editing with CRISPR-Cas is based on:
a bacterial defense system
What is the most likely genotype of the black cat progeny in the previous question?
aaBb or Aabb
Promoters are crucial for controlling expression of transgenes in the plant. Among the different plant promoters, constitutive promoters are often used. A constitutive promoter:
activates gene expression in all or most plant tissues throughout the life cycle
Where does transcription end?
at the terminator region of DNA
Considering the eukaryotic gene and its mRNA below, which letter in the diagram corresponds to each of the following key components?
b. promoter e. 5' untranslated region (5'UTR) c. 3' Untranslated region (3'UTR) a. Exons d. introns
The trp operon is a repressible operon. In the presence of tryptophan (effector molecule), the trp repressor:
binds to the operator and represses transcription
The genetic code is _________, meaning that an amino acid may be coded by more than one codon.
degenerate or redundant
A chromosome has the following segments, where • represents the centromere: A B C D E • F G What type of mutation is required to change this chromosome into the following one? A B A B C D E • F G
duplication
Which of the following will be translated?
exons
Which of the following factors did not contribute to Mendel's success in his study of heredity?
his study of plant chromosomes
Frameshift mutations can be produced by
insertions and deletions
One possible result of two double-strand breaks in a chromosome is that the fragment reattaches to the original chromosome in a reverse orientation. This is called:
inversion
What are NOT example types of RNAs are examples of non-coding RNAs? (select all that apply)
mRNA
A gene encodes a protein with the following amino acid sequence: Met-Lys-Ser-Pro-Ala-Thr-Pro* A base substitution mutation occurs in this gene, resulting in a protein with the amino acid sequence: Met-Lys-Pro-Pro-Ala-Thr-Pro* What type of base substitution mutation did most likely occur?
missense
During translation, the formation of peptide bonds between amino acids is carried out by:
rRNA
The number of GMO crops currently present in food markets in the United States is:
relatively small (<20)
The trp operon in E. coli is an example of a _______ operon under ______ regulation.
repressible, negative
What is the name of a mutation that doesn't have an observable effect on the phenotype
silent
diffusion
the process by which molecules move from an area of higher concentration to an area of lower concentration
Considering genetic map of chromosome 1 in Drosophila below, which 2 genes will be most often inherited together?
yellow body and white eyes
You are performing a chi-square test to find out if the deviation you find between the phenotypic ratios that you observed and those that you expected are due to chance. The degrees of freedom = 2 degrees in your experiment. You should reject your null hypothesis that chance alone produced the deviation if:
your chi-square value is greater than 5.991
In that same population of horses, what would be the frequency of the normal vision allele (B)?
0.8 p + q = 1, so p = 1 - 0.2 = 0.8
Let's consider the eggplant fruit color example from Lecture 5, which shows incomplete dominance. If a heterozygous F1 plant (Pp) that produces violet fruit is used in a testcross, what proportion of the progeny from this cross will be white?
1/2
How many copies of the H3 histone would be found in chromatin containing 25 nucleosomes?
50
How many copies of the H4 histone would be found in chromatin containing 25 nucleosomes?
50
Histone acetylation opens up chromatin, activating transcription. True or false?
true
Wobble base pairing allows the cell to decode 61 codons with less than 61 tRNAs. True or false?
true
What are the characteristics of the two daughter cells produced by mitosis?
-The two cells each contain about half the cytoplasm and organelle content of the original cell -The two cells each contain the same number of chromosomes as the original parent cell - The two cells are genetically identical to one another
What are not characteristics of the two daughter cells produced by mitosis?
-The two cells each contain half as many chromosomes as the original parent cell -The two cells contain the same amount of cytoplasm and organelles as the original parent cell
At what point(s) can gene expression be regulated in eukaryotes?
-Transcription -Post transcription -Post translation -Translation -Chromatin
Which of the following characteristics is associated with quantitative traits?
-environmental influence on phenotype -polygenic basis -continuous distribution
Correct statements about mutations
-many spontaneous mutations are generated by DNA replication errors -induced mutations can occur from exposure to certain chemicals and radiation -transitions are more frequent than transversion mutations
Through alternative splicing, one pre-mRNA can produce:
-more than one protein -more than one mRNA
Which of the following will NOT be transcribed?
-promoter -enhancer
Which of the following types of RNAs are examples of non-coding RNAs? (select all that apply)
-rRNA -tRNA -miRNA
Which of the following are regulatory sequences?
-silencer -operator -enhancer
Which of the following factors did contribute to Mendel's success in his study of heredity?
-use of mathematics -adoption of experimental approach -use of garden pea as a model species
Let's think of Mendel's seed texture characteristic, where round (R) is dominant over wrinkled seed (r). If a homozygous pea plant with round seeds (RR) is crossed with a heterozygous pea plant with round seeds (Rr), what proportion of the progeny will have wrinkled seeds?
0
In some horse populations, blindness can be a common trait. Let's assume this trait is controlled by one gene, where dominant allele B produces a normal sighted horse and recessive allele b leads to blindness in homozygosity. A wild horse researcher determines that the frequency of blind horses in a specific population of wild horses in Nevada is 0.04. What is the frequency of the blindness allele (b) in this population?
0.2 q2 is 0.04, so q = 0.2 (square root)
As we saw in lecture 7, patterned baldness is a sex-influenced trait. Remember the allele for baldness is dominant in males and recessive in females. For a cross between a bald mother and normal father, what is the probability of a bald son?
1
If a woman is homozygous normal and her husband is heterozygous (carrier) for an autosomal recessive disease, and they decide to become parents, what is the probability that they will have a healthy child (will not express the disease)?
1
The following genotypes are crossed: AaBbCcDd x AaBbCcDd. What is the probability of getting offspring with genotype aabbccdd?
1/256 (1/4x1/4x1/4x1/4)
If a cell with a diploid number of 32 chromosomes (2n=32) undergoes meiosis how many chromosomes are in each daughter cell?
16
In a species of fly, smooth wings (W) are dominant to wrinkled wings (w) and red bodies (R) are dominant to yellow bodies (r). A WwRr and wwrr fly mate and produce the following offspring: Smooth, red: 778 Wrinkled, yellow: 785 Smooth, yellow: 162 Wrinkled, red: 158 What is the recombination frequency for this cross?
17% RF = (162+158)/(778+785+162+158) X 100
If the percentage of cytosine in a double-stranded DNA molecule is 30%, what is the approximate percentage of thymine? (Clue: think of how bases pair and Chargaff's discoveries)
20%
Imagine species A has 2n = 14 chromosomes. What would be the chromosome number found in an individual of this species that is autotriploid?
21 A triploid individual is 3n. A common mistake is to assume that 3n means three times as many chromosomes as in a normal individual, but remember that normal individuals are 2n. Because n for species A is 7 and all genomes of an autopolyploid are from the same species, 3n = 3 × 7 = 21 chromosomes.
Imagine a diploid species with 2n = 36 chromosomes. How many chromosomes will be found in an individual of this species with a trisomy?
37
Considering the following transcript, which DNA strand could have been the DNA template for this RNA? 5′ AUGGCGUUU 3′
3′ TACCGCAAA 5′
Given the consensus sequence of the -35 box, 5' TTGACA 3', which of the following -35 box sequences would belong to the weakest promoter?
5' TAATCG 3'
Given the consensus sequence of the -35 box, 5' TTGACA 3', which of the following -35 box sequences would belong to the strongest promoter?
5' TTTACA 3'
The following nucleotide sequence is found in a short stretch of DNA: 5′-TCA-3′ 3′-AGT-5′ Imagine a spontaneous deamination of the cytosine occurs, which does not get repaired. After two rounds of cell division, what would be the mutant sequence that results from that cytosine deamination? Note: not all daughter cells will have the mutation.
5′-TTA-3′ 3′-AAT-5′
Based on the allele frequencies of B and b obtained in that same horse population of Nevada, what percentage of the population are expected to be carriers of blindness? Assume Hardy-Weinberg equilibrium.
Carriers will be heterozygous Bb, so 2pq = 2 x 0.8 x 0.2 = 0.32 x 100 = 32%
What happens in those cells where the telomerase gene is inactive?
Chromosomes shorten with each cell division
Under which of the conditions below would a lac operon produce the greatest amount of β-glactosidase? (Note that β-glactosidase is an enzyme encoded by one of the genes in the lac operon)
Condition 1
In the Avery, MacLeod and McCarty experiments, what conclusion would the scientists have drawn if only when the lipids of heat-killed S strain bacteria were destroyed the mice lived? Note: this is a hypothetical situation.
Lipid is the genetic material
Imagine this is a real sequence of a mRNA. What amino acid would it code for? (Note: do not assume that we start reading from the first nucleotide, you need to identify the ORF). 5' UUCUAUGAAAGUUGACG 3'
Met - Lys - Ala
During what period of the cell cycle is chromatin most condensed?
Mitosis
What is the outcome of a Robertsonian translocation?
One metacentric chromosome and one chromosome with two very short arms
A chromosome has the following segments, where • represents the centromere: A B C D E • F G What type of mutation is required to change this chromosome into the following one? A F • E D C B G
Pericentric inversion
What does it mean if a trait's H2 (broad sense heritability) is 0.5?
Phenotypic variation for this trait is due to both genetic differences and environmental factors
Base analogs are mutagenic because of which characteristic?
They are structurally similar to the normal bases
What is a codon?
Three nucleotides that encode an amino acid
DNA must associate with histone proteins to fit into the nucleus of a eukaryotic cell. True or false?
True
The loss of genetic diversity within a population increases its risk of extinction
True
what is the chromosomal condition of the individual whose karyotype is seen in the image?
Turner syndrome
Imagine that in your liver cells, a gene coding for a receptor of hormone A gets heavily methylated. What would be the consequence of it?
Your liver cells would not be able to respond to hormone A
In a inducible operon under negative regulation, the regulatory protein is synthesized as:
an active repressor
What is the role of gRNA (guide RNA) in the CRISPR-Cas9 system?
ensure that the Cas9 enzyme cuts at the right point in the genome
Frameshift mutations rarely change the function of the protein encoded by a gene, true or false
false
incorrect statement about mutations
mutations only occur in exons
Are genes controlling sex-influenced traits located on sex chromosomes?
no
Imagine a spontaneous depurination occurs in one of the nucleotides of the DNA molecule. Would that already be considered a mutation?
no
In 1941, Chaplin met a young actress named Joan Barry, with whom he had an affair. The affair ended in February 1942 but, 20 months later, Barry gave birth to a baby girl and claimed that Chaplin was the father. Barry then sued for child support. At this time, blood typing had just come into widespread use, and Chaplin's attorneys had Chaplin, Barry, and the child blood typed. Barry had blood-type A, her child had blood-type B, and Chaplin had blood-type O. Could Chaplin have been the father of Barry's child?
no
In principle, would it be possible to generate transgenic (GM) sugar or salt?
no
Xeroderma pigmentosum is a human disease associated with mutations in one or more genes involved in:
nucleotide excision repair
