Exam 4 (13, 14, 20, 26)
What are BACs and YACs?
BACs are bacterial artificial chromosomes YACS are yeast artificial chromosomes
What is aminoacylation?
tRNA charging
What was "one-gene: one-enzyme" get updated to?
"One-gene: one-polypeptide"
Why does tRNA typically have an idenosine in it's third anitcodon spot?
Because idenosine can bind to uracil, cytosine, and adenosine
What is translation?
Biological polymerization of amino acids into polypeptide chains
How do you create knockout mice?
1) Create target vector 2) Homologous recombination happens 3) Foreign DNA disrupts reading frame and produces nonfunctional protein
What is neurospora and who used it? What did they use it for?
Bread mold Beadle and Tatum To show that genes are directly responsible for synthesis of enzymes
How can genetic variation be estimated?
By comparing nucleotide sequences
In Blue-White screening, what do they blue spots represent? Why are they blue?
Colonies of DNA that are antibiotic resistant but do not contain target gene Because they have an in tact lacz gene that cleaves the x-gal in the agar plate
What do restriction enzymes do?
Cut DNA at specific sites
Where does translation occur in eukaryotes?
Cytoplasm
A scientist is troubleshooting the synthesis of a cDNA library. The scientist performs both a Northern and a Southern blot. The Northern blot demonstrated the presence of RNA while the Southern blot indicated that no cDNA was present in the sample. What is likely to be the cause of the failed synthesis of the cDNA library? A. proper primers B. too many dNTPs C. temperature too cold for annealing D. defective reverse transcriptase
D
What is the Hardy-Weinberg equation?
p^2 + 2pq + q^2 = 1
An mRNA that is being produced comes off of the ________.
Template strand in both bacteria an eukaryotes
Name and define the four protein structures
1) Primary: Sequences of amino acids 2) Secondary: a-helix and B-pleated sheets 3) Tertiary: Three dimensional 4) Quaternary: More than one polypeptide chain
How are new proteins created?
1) Transposons: "Jumping genes" 2) Errors during DNA recombination
What are the 3 steps of PCR?
1. Denaturation 2. Annealing 3. Extension
Transformation of cells using the technique of heat shock requires which of the following? A. the use of calcium ions B. the use of calcium and brief exposure to elevated temperature C. brief electric shock D. the use of zinc ions E. brief exposure to elevated temperature
B
Using mitochondrial genome to study the evolution of populations is easier because: A. it is a smaller genome B. it is maternally inherited C. its genes provide our energy and this is prerequisite for evolution
B
What event occurs during translocation? A. The two ribosomal subunits join to form a complex. B. mRNA shifts in the 5' direction along the ribosome. C. The polypeptide is cleaved from the terminal tRNA. D. Amino acids are added to the polypeptide chain.
B
What signals termination of translation in bacteria? A. a tRNA specific to the stop codon enters the ribosome's A site B. RF1 and RF2 C. EF-Tu and EF-G D. ribozymes E. the stop amino acid is attached to the growing peptide chain
B
Which method is often used to analyze proteins and nucleic acids by physical separation when estimating genetic variation in populations? A. absorption spectrophotometry B. electrophoresis C. centrifugation D. in situ hybridization E. fluorometry
B
Which of the following best describes a cloning vector? A. The direction in which DNA is cloned. B. A DNA molecule that accepts DNA fragments and replicates the fragment in a host. C. The fragment of DNA encoding a gene of interest. D. A DNA molecule that accepts DNA fragments and degrades them in a host.
B
Which level of protein structure is stabilized by hydrogen bonds between groups along the polypeptide backbone? A. Primary B. Secondary C. Tertiary D. Quaternary
B polypeptide, not peptide
Which of the following are most likely synonymous codons? A. 5'-ACG-3' and 5'-GCG-3' B. 5'-CUU-3' and 5'-CUC-3' C. 5'-GAU-3' and 5'-AUC-3'
B. Wobble hypothesis
How many different codons code for amino acids? A. 20 B. 61 C. 3 D. 64
B. 61 There are 61 codons that code for amino acids and three stop codons that do not code for an amino acid.
A particular mRNA makes a protein that has an unformylated methionine as its first amino acid. Did this mRNA come from a bacterial or a eukaryotic cell? A. Bacterial cell. Bacterial mRNA code for proteins starts with an unformylated methionine whereas eukaryotic mRNA code for proteins starts with a formylated methionine. B. Eukaryotic cell. Eukaryotic mRNA code for proteins starts with an unformylated methionine whereas bacterial mRNA code for proteins starts with a formylated methionine. C. The cell cannot be determined, because both eukaryotic and bacterial mRNA code for proteins may start with a formylated or unformylate methionine. D. Neither bacterial nor eukariotic cell, because no mRNA code for proteins starts with an unformylated methionine.
B. Eukaryotic cell. Eukaryotic mRNA code for proteins starts with an unformylated methionine whereas bacterial mRNA code for proteins starts with a formylated methionine.
What are the 3 types of nonrandom mating?
1. Positive assortive 2. Negative assortive 3. Inbreeding
What are the 3 types of RNA editing? Where are these types prevalent?
1. Substitution 2. Insertion 3. Deletion Mitochondria and chloroplasts
How much of the Lambda Phage Vector Systems can be used without impacting function?
1/3
What is the average time for speciation?
100,00 to 10 million years
How many RNA polymerases do eukaryotes have?
3
When did Homo sapiens originate?
300,000 years ago
Which region is the promoter in?
5'
Which side of the mRNA enters the ribosome?
5'
How many codons and amino acids are there?
64 codons 20 amino acids
A PCR was designed to clone a DNA sequence of 1.5 kb. When the products were run on an agarose gel, there was a smear of bands ranging from 1.5 kb to 6 kb. Which of the following is a reason for this result? A. one of the primers did not bind B. the thermocycler malfunctioned C. the polymerase denatured D. the polymerase overran the reverse primer
A
All the colonies growing in the petri dish after transformation have been selected to: A. to be resistant to ampicillin B. to contain the gene of interest C. they are normal bacterial cells and have not been selected yet.
A
Assuming that an amino acid sequence is 250 amino acids long, how many different molecules, each with a unique sequence, could be formed? A. 20^250 B. 250 X 20 X 2 C. 250^20 D. 250 X 20
A
Fluorescence in situ hybridization is another way to visualize the presence of a nucleotide sequence. Which of the following is an advantage of FISH over Northern and Southern blots? a. Blotting is not used in FISH. b. Probes are not needed in FISH. c. There are no advantages to FISH over Northern and Southern blots. d. Fluorophores are not used in Northern or Southern blots.
A
Genetic drift is primarily associated with what size breeding populations? A. very small B. very large C. mid-sized D. Genetic drift has the same effect on all population sizes.
A
If I am looking for a specific DNA sequence in a genome I should use: A. Southern Blot B. Northern Blot C. Western Blot D. FISH
A
Sanger sequencing method's key component was: A. ddNTPs B. dNTPs C. Mg D. DNA polymerase E. Primer F. DNA template
A
Taq polymerase is used in PCR reactions because: A. is more thermostable B. is more efficient than regular eukaryotic DNA polymerases C. is much cheaper than using E. coli DNA polymerase
A
What single event is probably common to all occurrences of speciation? A. reproductive isolation B. genetic bottleneck C. genetic drift D. founder effect
A
When choosing a restriction enzyme for use in recombinant DNA technologies, it is often preferred that the enzyme generate cohesive, or "sticky," ends. Why is this preferred? A. The sticky ends have hydrogen bonds that help re-anneal the cut DNA. B. The sticky ends stick to the purification medium making the fragments easier to purify. C. The sticky ends do not have hydrogen bonds to help in re-annealing the cut DNA. D. The sticky ends make the DNA bind tighter to any cut DNA. E. The sticky ends prevent the DNA from re-annealing to any DNA.
A
Which is the following is not a necessary feature of a good cloning vector? a. The ability to carry DNA fragments of up to 200 kb b. The ability to be replicated c. Restriction site(s) for the insertion of a foreign DNA fragment d. A selectable marker gene e. The ability to be isolated from the host cell
A
Which of the following is never found in the A-site of the ribosome? A. Initiator tRNA^met B. Release factor C. Aminoacyl tRNA D. tRNA bearing the growing polypeptide chain
A
ddATP, ddTTP, ddCTP, and ddGTP are labeled with red, green, yellow, and blue fluorescent dyes, respectively. A five-base read from a sequencing reaction produced the following color sequence, read by the computer: red, yellow, yellow, green, green. What is the sequence of the template DNA? a) ACCTT b) AAGGT c) TGGAA d) TTCCA
A
tRNAs _____. a. have double-stranded regions b. contain unusual nucleotides, encoded by genes with nonstandard bases c. can be recognized by several aminoacyl-tRNA synthetases d. can carry more than one type of amino acid per molecule e. consist of two subunits
A Regions of tRNA molecules fold back and base-pair with complementary regions within the same molecules, creating secondary structures that are double-stranded
Which of the following best describe(s) the function of the 5' mRNA cap? A. To protect the transcript from degradation B. It provides a site for ribosome binding in the cytoplasm. C. Termination of transcription D. To provide a binding site for poly(A) polymerase
A & B
What does it mean for the genetic code to be degenerate?
A given amino acid can be specified by more than one triplet codon
What is a nonsense mutation?
A mutation that produces a stop codon that produces a partial polypeptide
What does it mean for the genetic code to be nearly universal?
A single coding dictionary is used by viruses, prokaryotes, archaea, and eukarya
Rhizobium radiobacter
A soil bacterium which causes tumors
Define cladogenesis
A speciation pattern which exhibits branching of populations
Where do various forms of posttranscriptional processing in eukaryotes take place on the mRNA A. Alteration of 5' end B. Addition of amino acid sequences C. Alteration of 3' end D. Internal processing
A, B, C
Which of the following statements is true? A. The amino terminus of a polypeptide is encoded toward the 5' end of the mRNA B. The carboxy terminus of a polypeptide is encoded toward the 5' end of the mRNA C. The amino terminus of a polypeptide is encoded toward the 3' end of the mRNA D. The terminator in mRNA encodes the stop codon
A.
Which type of mutation helped lead to the understanding that the genetic code is based on triplets? A. Frameshift B. Base substitution C. Missense mutation within the promoter D. Nonsense
A. Frameshift
Start and stop codons?
AUG-codes and initiates UAA, UAG, UGA-only terminates
What is the 3' end of tRNA caalled?
Acceptor region
What does an Inbreeding Coefficient of 1 mean?
All individuals are homozygous for alleles derived from common ancestors
Why are introns important?
Alternative splicing Exon shuffling MicroRNA Cis regulatory elements
What are the 3 components of amino acids?
Amino group Carboxyl group R group
What is the enzyme that catalyzes tRNA charging?
Aminoacyl tRNA Synthetase
What is an exon?
An expressed sequence of DNA; codes for a protein
What is a probe?
Any DNA or RNA sequences complementary to a target gene
What does it mean for the genetic code to be nonoverlapping?
Any individual ribonucleotide within mRNA is only part of one triplet
A mutation in EF-Tu would have a DIRECT effect on which part of translation? A. The small and large subunits would not bind. B. The next tRNA would not be able to enter the A site of the ribosome. C. The peptide bond formation would be blocked. D. The polypeptide would form, but translation termination would be blocked. E. Translocation would be directly blocked.
B
During eukaryotic translation initiation, the _____ serves a role analogous to the Shine-Delgarno sequence in bacteria. a. poly-A tail b. 7-methylguanosine (m7G) cap c. initiator d. TATA box
B
Genetic drift arises from all the following EXCEPT ________. A. a founder effect B. mutations C. a genetic bottleneck D. a small breeding population
B
Northern blots are used to study what type of molecule? a) Proteins b) RNA c) DNA d) RNA and proteins
B
Nutritional mutants in Neurospora can be "cured" by treating the medium with substances in the defective metabolic pathway. What determines whether the mutant strain (auxotroph) is "cured" by a particular substance? A. The first substance in the biochemical pathway needs to be added. B. The substance needs to be added after the metabolic block in the biochemical pathway. C. The substance needs to be added before the metabolic block in the biochemical pathway. D. The substance to be added depends on other substances in the media.
B
Obtaining blue bacterial colonies after transformation means: A. the bacterial cells do not carry the engineered plasmid B. the bacterial cells do carry the engineered plasmid but not the insert (gene of interest) C. the bacterial cells do carry the engineered plasmid with the insert
B
Protospacer adjacent motifs, PAMs, allow bacteria to do which of the following? A. recognize and integrate foreign DNA B. recognize and digest foreign DNA C. recognize proper spacing for bacterial transcription initiation D. recognize and digest their own DNA
B
So, the advantage of having inosinic acid in tRNA is connected to the fact that: A. this nucleotide forms a ester bond with the codon in mRNA B. this nucleotide can form hydrogen bonds with more than one nucleotide
B
The generation of a knock-out organism generally requires all the following EXCEPT ________. A. embryonic stem cells B. knowledge of the sequence product C. a selectable marker D. knowledge of the target sequence E. a targeting vector
B
The genomics era began with the development of which of the following? A. whole-transcriptome sequencing B. whole-genome sequencing C. PCR D. third-generation sequencing
B
There are multiple cloning vector types in modern recombinant DNA technology ranging from plasmids to viral vectors. Which vector type is most useful when cloning an insert of approximately 500kb? A. human artificial chromosome B. yeast artificial chromosome C. bacterial artificial chromosome D. bacterial plasmid E. viral vector
B
This is thought to be the most common mechanism of action for natural selection because most traits do not appear to change drastically over time. A. Directional Selection B. Stabilizing Selection C. Disruptive Selection
B
To study gene expression, scientists use to build: A. Genomic libraries B. cDNA libraries
B
All of the following are examples of posttranslational modifications, EXCEPT________. A. Individual amino acid residues are sometimes modified, such as adding a phosphates, acetyl, or methyl groups can be added. B. Polypeptide chains can be cleaved to produce a shorter and functional polypeptide. C. Polypeptides can be degraded and then reassembled to produce entirely different sequenced polypeptides. D. Prosthetic groups, such as metals or vitamins, can be added. E. The N-terminal amino acid is often removed or modified.
C
All of the following are involved in the process of tRNA charging EXCEPT __________. A. amino acids B. aminoacyl tRNA synthetase C. rRNA D. ATP
C
Assume that a plasmid (circular) is 2800 base pairs in length and has restriction sites for EcoRI at the following locations: 400, 700, 1400, and 2600. Give the expected sizes of the restriction fragments following complete digestion with EcoRI. A. 400, 1200, 1600 B. 700, 400, 1400, 2600 C. 300, 600, 700, 1200 D. 200, 400, 700, 1200 E. 300, 700, 2200
C
During initiation in bacterial translation, a particular mutation causes the premature binding of the large ribosome subunit to the small ribosome subunit. Which component of initiation is not working properly? A. Shine-Dalgarno sequence on the mRNA B. IF1 C. IF3 D. IF2 E. Ribosome's E site
C
During the elongation phase of translation, charged tRNAs enter the ribosome at the ______. a. E site b. P site c. A site d. Shine-Delgarno site e. G site
C
Individuals with phenylketonuria cannot convert phenylalanine to tyrosine. Why don't these individuals exhibit a deficiency of tyrosine? A. Tyrosine is a nonessential amino acid. B. Phenylalanine and tyrosine are needed in only small amounts. C. Both phenylalanine and tyrosine can be obtained from the diet. D. Both phenylalanine and tyrosine are nonessential amino acids.
C
The following individuals do not get infected with the HIV virus A. Individuals with a perfect sequence for the CCR5 protein B. Individuals with an insertion in the CCR5 gene C. Individuals with a deletion in the CCR5 gene
C
The following is the order of steps when preparing a Southern Blot: a) Extract DNA, transfer DNA fragments to membrane via blotting, hybridize membrane with probe, expose membrane to X ray film, develop Xray and observe band patterns b) Extract DNA, digest DNA with restriction enzymes, transfer DNA fragments to membrane via blotting, run a gel, hybridize gel with probe, expose gel to X ray film, develop Xray and observe band patterns c) Extract DNA, digest DNA with restriction enzymes, run a gel, transfer DNA fragments to membrane via blotting, hybridize membrane with probe, expose membrane to X ray film, develop Xray and observe band patterns d) Extract DNA, run a gel, hybridize membrane with probe, expose membrane to X ray film, develop Xray and observe band patterns
C
When a peptide bond is formed between two amino acids, one is attached to the tRNA occupying the P site and the other _______. A. is attached through hydrogen bonds to the mRNA B. is free in the cytoplasm C. is attached to the tRNA occupying the A site D. is attached to the tRNA occupying the E site
C
Which features make yeast artificial chromosomes (YACs) an excellent cloning tool? a. YACs are large but low copy number plasmids that can accept DNA inserts in the 100- to 300-kb range. b. The YAC allows for the expression of bacterial genes. c. In their linear form, YACs contain telomeres at each end for stability, an origin of replication, and they can be used to clone up to 2-Mb pairs of DNA. A YAC also contains a yeast centromere along with selectable markers and a number of restriction sites. This allows for the insertion of up to 2-Mb pairs of DNA. d. Eukaryotic genes are relatively small. Cloning into a YAC allows for the function and the structure of these genes to be studied.
C
Which general term is used to group various biological and behavioral properties of organisms that act to prevent or reduce interbreeding? A. inbreeding B. phyletic evolution C. reproductive isolating mechanisms D. genetic divergence E. allopatric speciation
C
You are interested in knowing whether the addition of estrogen to your cell culture induces expression of mRNA from your gene of interest. Of the following choices, a good way to determine that is using __________. a. Southern blot b. Western blot c. reverse transcriptase PCR (RT-PCR) d. transgenic female animals e. next-generation sequencing
C
Which of these DNA sequences is palindromic when double-stranded? a. 5'-ATGGTA-3' b. 5'-ATGATG-3' c. 5'-ATGCAT-3' d. 5'-TATCGC-3' e. 5'-CCCCCC-3'
C A palindromic DNA sequence is identical on both strands when read in the 5'to 3' direction. 5'-ATGCAT-3' 3'-TACGTA-5' The sequence 5'-ATGCAT-3' is exactly the same on both strands.
All of the following may occur during posttranslational modification of a protein EXCEPT A. addition of phosphate groups B. removal of N-terminal amino acid C. removal of introns D. addition of metals to create tertiary or quaternary structures
C Introns are removed from the mRNA posttranscriptionally in eukaryotes.
What is the function of the Shine-Dalgarno sequence? A. Base-pairing with the mRNA to align the preinitiation complex at the start codon B. Specification of the transcription initiation site in bacteria C. Specification of the authentic start codon in bacterial mRNA D. Specification of the authentic start codon in eukaryotic mRNA
C.
What type of structure does tRNA have?
Cloverleaf
What are the two types of ends left behind after restriction enzymes cut DNA?
Cohesive ends Blunt ends
Which of the following statements about fMet (N-formylmethionine) is true? A. fMet is the first amino acid in virtualy all mature functional proteins in bacteria? B. FMet is sometimes found at internal positions in mature functional proteins in bacteria C. fMet is never found in mature functional proteins in bacteria D. fMet is sometimes found in mature functional proteins in eukaryotes
C. Formyl group gets removed during posttranscriptional modifications
The chromosome of phage φX174 encodes nine proteins consisting of a total of more than 2300 amino acids, even though the size of its genome predicts that it should be able to code for only 1795 amino acids. The reason for this discrepancy is? A. Frameshift mutation B. Alternative splicing C. Overlapping reading frames D. Enhancers
C. Overlapping reading frames
What are the limits of PCR?
Cannot amplify long section You have to know gene well to make primers Minor contaminants cause problems
What is a vector, in terms of DNA? What do they typically have for identification?
Carriers of foreign DNA molecules Selectable gene marker
What protein does the CRISPR process use?
Cas9
What does a Southern blot detect? How does it do this?
Certain clones in a library Fragments are created and separated using electrophoresis Hybridization using labeled probes creates glowing areas under x-ray
What is the effect random mating has on genotype and allele frequency?
Changes genotype frequency but not allele frequency
How do proteins get folded?
Chaperone proteins
The consensus sequences in E. coli's promoter are
Cis-acting elements
What controls transcription regulation in eukaryotes?
Cis-acting enhancers and silencers
Considering the types of side chains on amino acids and their relationship to protein structure, where are the amino acids with hydrophobic side chains most likely to be located? A. Hydrophobic side chains will alternate with hydrophilic side chains. The hydrophilic side chains will hide the hydrophobic side chains from the water environment. B. Hydrophobic side chains will form a hydrophobic cluster folding the protein in a single globule. C. Closer to the water environment and in the exterior portion of the molecule. D. Away from the water environment and in the interior portion of the molecule.
D
High throughput sequencing takes advantage of automated reading of sequencing data. Which of the following assists in automating the sequencing readout? A. fluorescently tagged dNTPs B. radioactive ddNTPs C. radioactive dNTPs D. fluorescently tagged ddNTPs
D
If I want to locate a specific DNA sequence in a tissue, I should use: A. Southern Blot B. Northern Blot C. Western Blot D. FISH
D
Mutation and migration introduce new alleles into populations. What is the most likely principal force that will shift allelic frequencies within large populations? A. disruptive selection B. stabilizing selection C. directional selection D. natural selection
D
Restriction enzymes are used in all of the following molecular biology techniques EXCEPT __________. A. cloning DNA into vectors B. creating DNA libraries C. mapping studies D. PCR
D
Sanger sequencing is based on the order in which ddNTPs are added to a growing polynucleotide. Why are ddNTPs integral to the Sanger sequencing method? A. They do not have a 2 hydroxyl, which does not allow the extension of the polynucleotide. B. They have a 2 hydroxyl that allows for extension of the polynucleotide. C. They have a 3 hydroxyl that allows for extension of the polynucleotide. D. They do not have a 3 hydroxyl, which does not allow the extension of the polynucleotide.
D
What are the genetic consequences of inbreeding? A. For a given allele, inbreeding increases the proportion of heterozygotes in a population. B. For a given allele, inbreeding increases the proportion of males and females in a population. C. For a given allele, inbreeding increases the proportion of genotypes in a population. D. For a given allele, inbreeding increases the proportion of homozygotes in a population.
D
What is the most serious drawback to using library screening to study genetics? A. The promoter of the gene must be known in order to design primers to amplify the gene in the library. B. The sequence of adjacent genes must be known in order to identify all the copies of the gene in the library. C. The product of the gene must be known in order to design enzyme probes to locate the gene in the library. D. The sequence of the gene must be known in order to design probes to locate the gene in the library.
D
Which of the following elements is not found in a plasmid? A. Polylinker B. Antibiotic resistance C. lacZ gene D. Lambda arms
D
Which of the following statements about a Neurospora valine auxotroph is true? A. The cells cannot grow on complete medium. B. The cells can grow on minimal medium. C. The cells can grow on minimal medium + histidine. D. The cells can grow on minimal medium + valine.
D
Which of the following statements best describes the function of aminoacyl tRNA synthetase? A. It provides the energy required to attach a specific amino acid to a tRNA molecule. B. It helps tRNA synthesize proteins. C. It synthesizes tRNA molecules. D. It attaches a specific amino acid to a tRNA molecule.
D
Which region of a tRNA molecule binds to amino acids? A. Codon loop B. Anticodon loop C. Variable loop D. 3' end
D
During bacterial translation initiation, the mRNA _____. a. binds to the large subunit b. is oriented so that the AUG start codon is in the A site c. only binds f-met tRNA after the entire ribosome has been assembled d. is oriented by its Shine-Delgarno sequence through base-pairing with an rRNA e. requires ATP hydrolysis for binding to the ribosomal subunit
D Translation initiation involves binding of the mRNA to the small subunit though base-pairing of its Shine-Delgarno sequence to the 16S rRNA of the small ribosomal subunit. This orients the AUG codon in the P site. Now, the f-met tRNA will bind to the AUG codon, and the large subunit will be attached. This requires hydrolysis of GTP.
An aminoacyl tRNA synthaseValine is mutated so that it now attaches the amino acid glycine to the tRNAValine instead of valine. What will happen at translation? a. There will be glycines at all valine positions and valines at all glycine positions. b. There will be valines at all glycine positions and glycines at all valine positions. c. There will be valines at all glycine positions and at all valine positions. d. There will be glycines at all glycine positions and at all valine positions. e. There will be no translation.
D Because the tRNAValine will still recognize the valine codon, it will attach whatever amino acid it has been charged with. Due to the mutation, it is now charged with glycine, so that will be inserted instead of valine. However, the glycine codons will still be recognized by their tRNAGlycine and will still place glycines at these "normal" positions.
Translation in bacteria is directly dependent on all of the following associations except _______. A. complementary base pairing between mRNA and rRNA B. complementary base pairing between mRNA and tRNA C. association of the 30S and the 50S ribosomal subunits D. complementary base pairing between mRNA and DNA
D.
Which of the following molecules is not required for a PCR reaction? A. DNTPs B. Primer C. DNA D. Ligase
D. Nothing is cut so ligase is not need
What is RNA polymerase?
Enzyme that directs synthesis of RNA using DNA template
What is used as a glue in DNA fragment repair?
DNA ligase
What is recombinant DNA?
DNA produced by artificially combining DNA from different sources
What are consensus sequences?
DNA sequences that are homologous in different genes of the same organism
How are peptide bonds formed?
Dehydration facilitates bond between carboxyl group and amino group
What is gene knock-in?
Increasing the expression of a gene or genes
What are the stages of translation?
Initiation, elongation, termination
What does the R group determine in amino acids?
Determines type of amino acid, and whether it's polar or nonpolar
What does Sanger sequencing use? What do they do?
Dideoxynucleotides Stop DNA polymerase at certain places
What is gene knockout?
Disrupting or eliminating certain genes to observe what happens
What is negative assortive mating?
Dissimilar phenotypes are more likely to mate
Creutzfeldt-Jakob, Huntington, Alzheimer, and Parkinson disease are all characterized with which part of protein synthesis? A. initiation B. N-terminal modification C. termination D. elongation E. protein folding
E
DNA ligase ________. A. cuts the DNA to produce sticky or blunt ends B. adds bases into a growing DNA molecule C. removes bases from a DNA molecule D. reconnects the bases together between the DNA strands E. reconnects the phosphodiester linkage between bases on the same strand of DNA
E
In the polymerase chain reaction, the purpose of the step in which the temperature is between 70°Celsius and 75°Celsius is _____. a. to denature the DNA b. to denature the polymerase c. to allow the primers to anneal d. to allow the primers to release from the template e. to allow DNA polymerase to synthesize DNA
E
Modular portions of a protein that fold into stable conformations with specific functional capabilities are referred to as ________. A. protein subunits B. protein quaternary structures C. protein secondary structures D. protein chaperones E. protein domains
E
The β chain of adult hemoglobin is composed of 146 amino acids of a known sequence. In comparing the normal β chain with the β chain in sickle cell hemoglobin, what alteration is one likely to find? A. extensive amino acid substitutions B. frameshift substitutions C. glutamic acid replacing valine in the first position D. trinucleotide repeats E. valine instead of glutamic acid in the sixth position
E
What is the purpose of the dideoxynucleotides in computer-automated DNA sequencing? a. To cause defined chain termination b. To label the synthesized DNA c. To help transfer the DNA to the membrane d. To aid in electrophoresis e. Both a and b
E
A protein is 300 amino acids long. Which of the following could be the number of total nucleotides in the section of DNA that codes for this protein? (Remember: DNA is double-stranded.) A. 300 B. 900 C. 3 D. 100 E. 1800
E Each amino acid needs 3 nucleotides, a codon, to code for it. This means 900 nucleotides, but DNA is double stranded so double 900.
Archibald Garrod's work suggested that _____. a. DNA is the genetic material b. each gene codes for a unique ribosome c. each gene is associated with the production of a single polypeptide d. biologically active DNA is in a double-helical structure e. inherited factors control metabolic activities
E Garrod studied the inherited disorder alkaptonuria, which is inherited as an autosomal recessive and is a result of altered metabolism. Garrod concluded that inherited factors (today's "genes") influence metabolism. +
Sickle cell anemia affects the following protein structure: A. Primary B. Secondary C. Tertiary D. Quaternary E. All of them
E. Though the problem originates in the primary structure, the problem affects all layers
What does it mean for the genetic code to be unambiguous?
Each codon specifies only one amino acid
What do enhancers and silencers do and where are they found?
Enhancers increase transcription levels and silencers decrease them Upstream, within and downstream of a gene
Polynucleotide Phosphorylase
Enzyme that catalyzes production of synthetic mRNAs
What is closed loop translation?
Eukaryotic translation, where the 5' cap and 3' poly-a tail of mRNA are bound together and ribosome recycling occurs
What does a Northern blot detect?
Expression of RNA
What is a plasmid? Where are they abundant?
Extrachromosomal double stranded DNA molecule Bacteria
What does the Elongation Factor Tu (EF-Tu) do?
Facilitates entry of charged tRNAs into the A site
The enzyme EF‑Tu catalyzes the formation of a peptide bond between the amino acid held by the tRNA in the A site and the elongating amino acid chain held by the tRNA in the P site. True or False?
False Peptidyl transferase is the enzyme that catalyzes the formation of peptide bonds during translation. EF‑Tu is an elongation factor that facilitates the entry of charged tRNAs into the A site.
What is FISH and why is it used?
Fluorescent in situ Hybridization Used for in-tissue expression observation
What are the two ways genetic drift occurs?
Founder effect, genetic bottleneck
What does an Inbreeding Coefficient of 0 mean?
No individual has two alleles derived from common ancestral copy
Two types of DNA libraries and their differences?
Genomic library -Contains introns and exons -Made by cutting an ligating DNA into fragments cDNA library -Only contains exons -Shows genes expressed in that moment -Uses reverse transcription to obtain DNA copies made from mRNA
Define anagenesis
Gradual transformation of one species into another
Two ways that termination occurs in bacteria and which is more often?
Hairpin secondary structures 80% Rho termination factors 20%
What does the TATA box do?
Helps determine start transcription
Why don't lethal recessive alleles disappear?
Heterozygotes are not selected against
In regards to HIV and the CCR5 gene, who are immune and who are susceptible but progress more slowly?
Homozygous recessives Heterozygotes
What type of breeding is most commonly found to affect genotype frequencies?
Inbreeding
What is transformation?
Introduction of DNA from environment
What are the two parts of the monosome?
Large and small subunit
What are polyribosomes?
Long strands of RNA with many ribosomes attached
Define Phenylketonuria
Metabolic error where individual cannot convert phenylalanine to tyrosine, mental retardation occurs
Define Alkaptonuria
Metabolic error where individual cannot metabolize homogentisic acid
What are prions?
Misfolded proteins
Who was responsible for the Neutral Theory? What does it say?
Motoo Kimura Most amino acid mutations are detrimental
What is an intron? What doesn't have these?
Sequence of DNA that is not involved in coding for a protein Bacteria
When population increases does genetic drift occur more readily?
No, less readily
Where does transcription occur for eukaryotes?
Nucleus
What do restriction maps show?
Number of, order, and distance of enzyme cleavage sites
Who used the triplet binding assay to find many ribonucleotide inputs/outputs using chemically synthesized long RNA?
Nurenberg and Ledar
Who used RNA heteropolymers to decipher relative portions of many ribonucleotides?
Nurenberg and Matthaei
What does it mean for the genetic code to be commaless?
Once translation begins, codons lead with no break
How many amino acids can be bound to one tRNA? What are/is those/that amino acid(s) called?
One Cognate amino acid
Why is phage M52 often used?
Only 4 genes and 3,500 base RNA code
In ribosomes, during translation, in what order are the sites visited?
P site is first, then A is unblocked and tRNA goes there. Then the tRNAs flow A to P to E until termination
What kind of sequences to restriction enzymes recognize?
Palindromic
What was the first vector developed? What were they engineered to have?
Plasmids Convenient restriction sites Gene markers
What does PCR stand for? Why was it revolutionary? Who created it?
Polymerase Chain Reaction Rapid method of DNA cloning Kary Mullins
Homopolymers
Polymers made up of one type of repeating unit EG. AAA, GGG
What is the point of the Shine-Dalgarno sequence in prokaryotes?
Precedes AUG Orientates the mRNA by pairing with small subunit
Four points about chain elongation
Proceeds under direction of core enzyme Proofreading occurs Ribosomes are added to RNA chain Sigma subunits dissociates from holoenzyme
What is the term used for initial mRNAs undergoing alterations to become mature mRNA?
Processing
What marks the beginning of transcription and what recognizes this?
Promoter Sigma subunit
What does a Western blot detect?
Proteins
What is the most abundant macromolecule in cells?
Proteins
What are trans-acting elements?
Proteins that influence gene expression by binding to cis-acting elements
Which RNA polymerase is responsible for the widest range of genes in eukaryotes?
RNAP II
What are cis-acting elements?
Regulatory sequences located within the same molecule of DNA that they regulate
What are some differences with eukaryotic translation compared to prokayotic?
Requires more factors Ribosomes aren't free flooating and are bound to rough ER Close loop translation
What is the most common method of DNA sequencing?
Sanger Sequencing
What is positive assortive mating?
Similar genotypes are more likely to mate
What is Reverse Transcription PCR used for?
Studying gene expression
What is Quantitative Real-Time PCR used for?
Studying gene expression during periods of time
What is the wobble hypothesis?
The initial two ribonucleotides are often more critical than the last one
Genetic code is nearly universal except for where?
The mitochondria
In Southern Blot testing, what DNA fragments are glowing when exposed to the light?
The parts that your radioactive probe hybridized with
What does phosphorescence mean during qPCR? Why does this occur?
The targeted gene is being expressed As the DNA polymerase is doing its thing, the Reporter dye is released
What happens to DNA as guanine and cytosine content increases?
The temperature needed to denature it goes up
What discovery did James Darnell make?
There is pre-mRNA and it is processed in the nucleus It gains a 5' cap It gains a 3' tail Loses introns
Which direction do DNA fragments flow during electrophoresis?
They move to the positive end because DNA is negatively charged
In prokaryotic translation initiation, what is the job of initiation factor 3?
To attract mRNA to the small subunit
Different sets of human hemoglobins are found at different times in development. True or false?
True During embryonic and fetal development, the set of polypeptides found in hemoglobin is completely different from that found in the hemoglobin of adults.
The only two amino acids that are encoded by a single codon?
Tryptophan and Methionine
If there were six bases in DNA and still only 20 amino acids, how long would a codon need to be in order to specify an amino acid?
Two bases Using six bases in a two-base codon would yield 62 36 different combinations. That would be more than enough to encode all 20 amino acids and the stops.
What does PCR require to work?
Two primers Taq polymerase (heat stable polymerase)
What are expression vectors? What is their benefit?
Vectors designed to ensure expression of gene They can be transcribed and translated
What is the role of general transcription factors (GTFs)? a .GTFs bind to enhancers or silencers and regulate transcription b. GTFs bind to the core promoter and allow transcriptional initiation c .GTFs are cis-acting regulatory sequences d .GTFs regulate the length of the mRNA e .GTFs are part of the RNA polymerase II holoenzyme, and control transcription initiation
b. GTFs bind to the core promoter and allow transcriptional initiation
RNA editing can be the result of insertion/deletion editing. This results in _______________. a. Removal of introns after transcription b. Addition (and subsequent removal) of poly-A tail as part of regulation of expression c. Removal of T's added to mRNA by mistake and replacement with U's d. Changes to the mRNA sequence after transcription e. Switching one base for another
d. Changes to the mRNA sequence after transcription
Considering transcription initiation, the core promoter in eukaryotes is homologous to what in prokaryotes? a. rho b. Sigma 70 c. core enzyme d. Pribnow Box e. Goldberg-Hogness box
d. Pribnow Box