genetics exam 2
Every organism and chromosome recombines and the ones that do not suffer an increase in deleterious mutations and slower adaptation because they can not produce the best combinations of the existing variation.
...
An eukaryotic gene is 2378 bp long, it has 3 exons of lengths 367, 133 and 282 nucleotides long and produces a single transcript and a single mRNA. How long is the mRNA produced by this gene before polyadenylation? A) 782 nucleotides B) The information cannot be correct because the exons do not add up to a multiple of 3 C) 2378 nucleotides D) 1596 nucleotides E) None of the answers is correct
A
Cis regulation of a gene involves... A) DNA nearby B) transcription factors C) none of the answers is correct D) its coding sequence E) RNA
A
Genetic linkage leads to the production of a significantly greater than expected number ofgametes containing chromosomes with A) parental combinations of alleles. B) dominant alleles. C) allele combinations that are different from parental combinations. D) recessive alleles. E) mutant alleles.
A
How many molecules of double stranded DNA will be present after 7 cycles of PCR? Assume you are starting with a single double stranded DNA molecule. A) 128 B) 16 C) 64 D) 32 E) 256
A
In a genetic map there are 10 m.u. between two genes (A and D) in a genome and 60 m.u. between two other genes (J and O). What do we infer? A) genes J and O are farther apart from each other than A is from D B) the two sets of genes are in the same chromosome C) the first pair of genes is X-linked and the second is autosomal D) the two pairs of genes are in different chromosomes E) the second value must be wrong because you can not have more than 50 m.u. between two genes
A
On the first day of your internship in a molecular biology research lab, you are told to design ashort single-stranded DNA sequence that will base-pair with a mutated mRNA with sequence 5'CCACCUUCAG3'. Which of the following sequences would be the best choice? A) 5'CTGAAGGTGG3' B) 5'CCACCTTCAG3' C) None. DNA cannot pair with RNA D) 3'CCACCTTCAG5' E) 3'CTGAAGGTGG5'
A
The following is meant to be a list of the molecules that are necessary for splicing of a eukaryoticprimary messenger RNA as performed by the spliceosome. What item does not belong in thislist? A) mRNA B) proteins that are part of small nuclear ribonucloproteins that that form the spliceosome C) splicing factors D) small nuclear RNAs that are part of small nuclear ribonucleoproteins that form thespliceosome E) all of the molecules listed are necessary
A
We want to sequence the genome of a healthy mouse. Genomic DNA was extractedfrom lymphocytes and pooled together with liver DNA from the same healthymouse. What statement is correct? A) We can work with this mix as if it was DNA coming from the same tissue B) This DNA cannot be used now because we mixed genomic DNA from different tissues C) Only if we add DNA from the rest of the tissues we will have a good representation of the genome D) We can work with it as long as we added same amount of the DNA from the differentsources E) None of the statements is correct
A
What is one difference between DNA replication in bacteria versus eukaryotes? A) Eukaryotic chromosomes have many origins of replication, while bacteria have only oneorigin of replication. B) Eukaryotic chromosomes are replicated bidirectionally, while bacterial chromosomes arereplicated in one direction. C) The process is identical in bacterial and eukaryotic DNA replication. D) Bacterial chromosomes are replicated bidirectionally, while eukaryotic chromosomes arereplicated in one direction. E) Eukaryotic chromosomes have many origins of replication and replicate bidirectionally,while bacteria have only one origin of replication and replicate unidirectionally.36)9
A
What sentence is more accurate about how genes can be encoded in the genomes? A) genes can be encoded in either strand of double stranded DNA B) genes are encoded in proteins C) genes are always encoded in RNA D) genes can be encoded only in one of the strands of DNA E) none of the answers is correct
A
What type of bond is formed between the hydroxyl group of one nucleotide and the phosphate group of an adjacent nucleotide, forming the sugar-phosphate backbone of DNA? A) phosphodiester bond B) ester linkage C) ionic bond D) hydrogen bond E) glycosidic bond
A
Which of the following is not true of DNA? A) It is positively charged B) It is an acidic molecule C) It is most often double stranded D) It is more stable than RNA E) None of the answers is correct
A
Which of the following temperature cycles would you expect to see in a standard polymerase chain reaction (from denaturation to annealing to extension)? A) 95° → 55° → 72° B) 95° → 72° → 95° C) 75° → 95° → 45° D) 45° → 72° → 95° E) 95° → 72° → 55°
A
Which of these components would you use to distinguish whether a sample has been preparedfor a Sanger sequencing reaction or for a polymerase chain reaction? A) ddNTPs B) dNTPs C) DNA polymerase D) DNA primer E) DNA template
A
What genes from the list below are exceptions to the second law of Mendel of independent assortment? A) genes that are in different chromosomes B) genes that do not encode for proteins C) genes that are at a genetic distance of 30 mu D) genes without introns E) genes that are too long
C
Which of the following choices (I, II, III, IV) is NOT a mechanism of recombination in bacteria? I. transduction II. lytic cycle III. transformation IV. conjugation A) III only B) III and IV C) II only D) IV only E) I and II
C
he extraordinary accuracy of the DNA polymerase III enzyme lies in its ability to "proofread" newly synthesized DNA, a function of the enzyme's A) 5′-to-3′ exonuclease activity B) 3′-to-5′ polymerase activity. C) 3′-to-5′ exonuclease activity. D) 3′-to-5′ helicase activity. E) 5′-to-3′ polymerase activity
C
Studying ___ helps us place genes in a genetic/recombination map relative to each other and those can help position new mutations in the genome and study disease.
recombination
___ does not produce new variation. It produces different combination of existing variation. ___ does produce new variation.
recombination, mutation
The second law of Mendel (independent assortment) does not apply for genes on the ___ ___
same chromosome
The simplicity of the genetic information (A, T, C and G) allows for its easy manipulation (s__, P__ amplification and a lot more, genetic ___)
sequencing, PCR, engineering
Telomeres ___ every replication cycle in somatic cells but not in germline cells because there is telomerase. This contributes to aging and in some cancers, telomerase is on and makes them immortal.
shortens
___ is needed to extract information from DNA that is needed for life (i.e., the production of functional RNAs and proteins). ___ needs to be accessible (i.e., not condensed)
transcription, DNA
DNA polymerases need a __' end to add the dNTPs. RNA polymerases do not need a __' end to add the NTPs. (N= A, T, C, G)
3, 3
Now that we have expanded our knowledge of the structure and function of genes, the definition of gene has often become more operational although the classic definition still applies. Can you identify the definition of gene that we will be using in this course in the list below? A) Genes are regions of the chromosomes that encode for proteins B) Gene as the physical unit of heredity, composed of a DNA sequence that is transcribed and encodes for a protein or another functional transcript C) Genes are blueprints for enzymes D) Gene as the physical unit of heredity, composed of a DNA sequence that is transcribed and encodes for a protein or another functional transcript and its regulatory regions E) Genes as discrete units of inheritance that specifies an individuals' characteristic
B
The process by which Pneumococcus transfers DNA between heat-killed type SIII and living type RII cells rendering them virulent is known as ... A) transduction. B) transformation. C) conjugation. D) ligation. E) replication
B
Transcripts that encode polypeptides are produced by... A) RNA Polymerase I B) RNA Polymerase II C) RNA Polymerase IV D) RNA Polymerase III E) none of the above
B
What level/s of gene regulation that exist in eukaryotes does/do not exist in prokaryotes? A) all of the above B) chromatin remoldeling C) interactions of transcription factors with effectors D) regulation by transacting factors E) cis regulation
B
What statement/s below is/are incorrect about DNA and RNA polymerases. A) Both catalyze phosphodiester bond formation B) Both need a primer's 3' OH to start the polymerization C) Both are dependent on the presence of a template strand of DNA D) Both polymerize a nucleic acid in the 5' to 3' direction E) Both C and D are incorrect
B
n a dense genetic map there are 30 m.u. between two genes (A and J) in a genome and60 m.u. between two other genes (P and W). What do we infer? A) the genes are in the same chromosome B) there are more base pairs separating the second pair of genes C) the genes are in different chromosomes D) the first pair of genes is X-linked and the second is autosomal E) the second value must be wrong because you can not have more than 50 m.u.between two genes
B
How many molecules of double stranded DNA will be present after 5 cycles of PCR? Assumeyou are starting with a single double stranded DNA molecule. A) 24 B) 12 C) 32 D) 128 E) 6
C
What is required for DNA polymerase to initiate DNA strand synthesis? A) ATP and a short DNA primer synthesized by the enzyme topoisomerase B) ATP and a short RNA primer synthesized by the enzyme topoisomerase C) DNA polymerase initiates DNA strand synthesis without requiring any additionalenzymes. D) a short RNA primer synthesized by the enzyme primase E) a short DNA primer synthesized by the enzyme primase
D
What mRNA will be produced from the exonic region below? 5'ATCGCCATGCAGT3' A) 5' ATCGCCATGCAGT3' B) 5'ACUGCAUGGCGAU3' C) 3' AUCGCCAUGCAGU5' D) 5' AUCGCCAUGCAGU3' E) None of the above
D
A gene with 4 exons will have... A) 4 introns B) 2 introns C) 1 intron D) 3 introns E) 0 introns
D
Choose the correct statement about recombination. A) Gene conversion is not a form of recombination B) Eukaryotes do not recombine C) Virus do not recombine D) Recombination is not the primary source of variation, mutation is E) Bacteria do not recombine
D
E. coli cells are put into a medium containing tritiated (i.e., radioactive) thymidine for onegeneration only. What proportion of the cells will be labeled with radioactivity? A) 1/16 B) 1/8 C) 1/2 D) All E) 1/4
D
For the following fragment of the coding strand of a gene provide the sequence of the RNA that will be produced upon transcription. 5'ATCGACCTGATC3' A) 5'GATCAGGTCGAT3' B) 3'AUCGACCUGAUC5' C) 5'UTCGUCCTGUTC3' D) 5'AUCGACCUGAUC3 'E) 3'GATCAGGTCGAT5
D
How is DNA from a bacterial donor transferred to a recipient via general transduction? A) A pilus forms and connects the donor and recipient, with DNA transferred via the pilus B) DNA from the environment - which could be from the donor bacterial cell - is taken upby the recipient cell. C) An Hfr bacterial cell transfers parts of its chromosome to the recipient via conjugation. D) Viral components in the donor cell package bacterial DNA instead of phage DNA, andsubsequently infect a recipient cell with the donor DNA E) During fertilization, two gamete cells unit, thus creating a new diploid cell with bothparental genomes.
D
Polymerase chain reaction (PCR) allows you to... A) cut the genome in pieces B) produce single-stranded DNA products for sequencing C) ligate DNA segments D) amplify a DNA segment of known sequence E) amplify a DNA segment of your choosing in any eukaryotic or prokaryotic genome even if you do not know the sequence
D
What element in the list below is not a cis-acting element used in some genes during eukaryotic transcription. A) CAAT box B) Enhancer C) All of the listed elements are cis-acting element used in transcrition D) TATA binding protein E) TATA box
D
If you are thinking about both the applied and evolutionary importance of recombination, what is/are statement/s that you would make? A) Because many mutations are deleterious, populations would be better without any recombination. B) Recombination frequencies are very useful to find the gene underlying a phenotype. Since genes are in chromosomes and recombination frequencies between genes relate to their relative location they are very useful for mapping. C) It has been observed that all organisms recombine and shown that recombination has evolutionary importance because produces new combinations of alleles at different loci allowing selection to select more efficiently for the best allelic combinations. D) Recombination frequencies and mapping are nuisances. To find the genes underlying some phenotypes in the genome it would be better if all the genes were in different short chromosomes. E) B and C are correct
E
Telomerase is a retrotranscritptase enzyme that can ... A) synthesize DNA using RNA as template B) recruit proteins to bind telomeres and protect them C) elongate double-stranded DNA at the telomeres D) elongate one DNA strand at the end of linear chromosomes E) A and D are correct
E
Telomerase is and enzyme that... A) has retrotranscriptase activity B) is able to elongate one strand of DNA at the telomere alowing DNA synthesis of the otherstrand and maintaining telomere length C) is a ribonucleoprotein composed of a molecule of RNA and proteins D) has the ability to synthesize DNA using RNA as a template E) all the statements are correct
E
There are various definitions of gene and they have changed through time from the classic definition of gene first used by Johanssen in 1990 based on the concept developed by GregorMendel in 1866. Identify below the classic definition. A) Genes are regions of the chromosomes that encode for proteins B) Genes are blueprints for enzymes C) Genes are regions of DNA that produce functional transcripts D) Genes are regions in the chromosomes E) Genes as discrete units of inheritance that specifies an individuals' characteristic
E
Trans regulation of the transcription of a gene involves... A) cytoplasmic RNAs B) DNA nearby C) its coding sequence D) none of the answers is correct E) transcription factors and cofactors that bind DNA nearby
E
What is/are the role/s of histones in the eukaryotic nucleus? A) DNA packaging in nucleosomes B) facilitate interactions of RNA polymerase with promoter C) histone have a regulatory role because histone modifications lead to chromatin remodeling D) cis regulation of genes E) A and C are correct
E
What statement/s is/are correct about genes? A) genes can be encoded in either strand of the double-stranded DNA B) regulatory regions of genes are not part of how genes are currently annotated in genomes C) RNA genes encode for functional RNAs D) protein-coding genes encode for proteins E) all of the statements are correct
E
What would you use to transform an avirulent strain of the bacterium Pneumococcus into a virulent one? A) RNA B) lipids C) sugars D) protein E) DNA
E
Which of the following enzymes is required to link together Okazaki fragments with phosphodiester bonds? A) Primase B) DNA Polymerase I C) DNA Polymerase III D) Helicase E) DNA ligase
E
Which of the following steps of the pre-mRNA processing in a eukaryotic cell takes part in thecytoplasm? A) the removal of introns by two transesterification reactions B) addition of the 5′ 7-methylguanosine cap by the enzymes guanylyl transferase and methyltransferase C) cleavage at the 3′ end D) addition of up to 200 adenines on the 3′ end by polyadenylate polymerase E) none of the steps of processing of the pre-mRNA take part in the cytoplasm
E
Which post-transcriptional modification is made to the 5' end of prokaryotic messenger RNAs? A) removal of introns by the spliceosome B) addition of 7-methylguanosine C) cleavage of the transcription initiation signal D) addition of a variable number of adenines E) none of the above
E
Which type of event produces no recombinant products between two genes? A) triple crossover involving two non-sister chromatids between the genes B) single crossover involving two non-sister chromatids between the genes C) no crossover between the genes D) double crossover involving two non-sister chromatids between the genes E) C and D are correct
E
DNA also contains information in its ___ ___ (i.e., sequences that will be bound by proteins that will trigger replication, transcription, or histones and DNA modifications)
base pairs
Genetic information is passed to ___ cells and ___. To achieve this it undergoes semiconservative replication of a double helix
daughter, offspring
m.u. are ___ ___ recombination frequency (RF) at short distances, but at long distances m.u. keep ___ but RF asymptotically ___ to 50%. This because double, quadruple... crossovers do not lead to recombinants between far-apart genes.
equal to, increases, increases
Recombination frequency ___ with distance. Cotransformation frequency ___ with distance. Cotransduction frequency ___ with distance.
increases, decreases, decreases
