exam 2 multiple choice
The cellular organelle responsible for protein synthesis.
Which of these is NOT a character of the genetic code?
A. There are the same number of codons as there are amino acids.
B. The code is used by nearly every living organism.
C. Some amino acids have multiple codons.
D. The code is degenerate.
The sequences within mRNA that are spliced out (removed) are called
Experiments that are done outside a living cell are describe by the Latin term
The enzyme that makes RNA from a DNA template is
A. RNA-dependent DNA polymerase.
B. DNA-dependent DNA polymerase.
C. DNA-dependent RNA polymerase.
D. RNA-dependent RNA polymerase.
Transcription occurs in the ________ and translation occurs in the __________ of eukaryotic cells.
A. nucleus, cytoplasm
B. cytoplasm, nucleus
C. nucleus, nucleus
D. cytoplasm, cytoplasm
Ribosomes are composed of
A. tRNA and protein.
B. mRNA and protein.
C. rRNA and protein.
D. only proteins folded together.
An anticodon is a physical component of a/an _______ molecule.
What is one difference between using restriction endonucleases and mechanical shearing of DNA?
A. Restriction endonucleases digest at known specific sites while shearing occurs at random sites.
B. Restriction endonucleases digest at random sites while shearing occurs at known specific sites.
C. Restriction enzymes are a mechanical process while shearing occurs using proteins.
D. Restriction enzymes produce larger fragments on average than shearing.
Which of the following is an example of a recombinant DNA molecule?
A. a single-stranded RNA hybridized to a single-stranded DNA
B. a genomic fragment of human DNA ligated to a bacterial plasmid vector
C. a λ chromosome in a bacterial cell
D. a bacterial plasmid cut with a restriction enzyme
In Sanger sequencing, what causes DNA synthesis to terminate at a specific base?
A. chemicals that cleave DNA after particular bases
C. nucleotide triphosphates that lack a base
D. nucleotide triphosphates that lack a hydroxyl at the 3' position
E.nucleosides that lack a 5' phosphate
In gel electrophoresis of DNA, fragments move at different rates because they have different
A. charge densities.
D.amino acid compositions.
E. electrical strengths.
If DNA had 6 different bases with the two novel bases pairing with only each other, a restriction enzyme with a 4-base recognition sequence would be predicted to digest the DNA approximately everyrev: 03_19_2015_QC_C570
A. 125 bp.
B. 256 bp.
C. 425 bp.
D. 625 bp.
Why does a genomic library need more clones than what would be estimated by calculations to be complete?
A. There is a significant probability that some sequences would not be represented in a library if it was only the calculated size
B. The restrriction enzyme that is used to prepare the DNA for cloning will not digest certain sequences within the DNA.
C. The restriction enzyme used to prepare the DNA for cloning sometimes leaves a different sticky end
D. Restriction enzymes cleave DNA preferentially at the ends of open reading frames so coding regions are prefereentially cloned.
Where do restriction enzymes come from, and what is their normal physiological function?
A. Phage λ produces them and they replicate viral DNA.
B. Phage λ produces them and they confer antibiotic resistance.
C. They are yeast DNA replication enzymes.
D. Bacteria produce them to protect against viral invasion.
E. They are bacterial DNA replication enzymes.
The BLAST suite of programs can be used to
A. compare a nucleotide or amino acid sequence to databases from a variety of species.
B. display the reading frames of nucelotide sequence.
C. find the tissues that a nucleotide sequence might be expressed in.
D. analyze microarray data.
After digestion of DNA with a restriction endonuclease, which statement is true about the resulting DNA fragments?
A. They will have either a single stranded overhang or blunt ends, depending on the enzyme used.
B. They will have only blunt ends.
C. They will have only single stranded overhangs.
D. The result cannot be predicted because a single restriction enzyme can generate either single stranded overhangs or blunt ends.
Most polymorphisms do not result in a phenotypic difference since they are typically
A. nonsense mutations.
B. either missense or neutral mutations.
C. either silent mutations or are in non-coding regions.
D. either missense mutations or are in promoter regions.
SNP is the acronym for:
A. simple Northern probe.
B. single nucleotide polymorphism.
C. sample in situ probe.
D. simple nucleotide probe.
PCR cannot be successfully performed without
A. at least 100 starting DNA molecules.
B. at least some sequence information about the region to be amplified.
C. a cDNA version of the region to be amplified.
D. a section of at least 100 kb to amplify.
E. an undamaged, nondegraded DNA sample.
If a single DNA molecule is amplified by PCR, how many DNA molecules will there be after six cycles?
If a PCR amplified sample hybridizes with two allele specific probes, one normal and one mutant sequence, a carrier is identified if...
A. both probes give a signal.
B. neither sample gives a signal.
C. only the mutant probe gives a signal.
D. only the non-mutant probe gives a signal.
E. None of the choices is correct.
Which is the most frequent type of DNA polymorphism?
A. single base differences
E. changes in ploidy
The enzyme that some organisms use to replicate DNA at the 5' ends of chromosomes is called
A. DNA polymerase.
C. DNA ligase.
By weight, chromatin consists roughly of
A. 1/3 DNA, 1/3 histones, and 1/3 nonhistones.
B. 1/3 DNA and 2/3 acidic proteins.
C. 1/3 DNA, 1/3 histones, and 1/3 basic proteins.
D. 1/4 DNA, 1/4 RNA, 1/4 histones, and 1/4 nonhistones.
The first level of compaction of DNA consists of
A. DNA winding around histones to form small nucleosomes.
B. tight coiling of DNA with nucleosomes into higher order structures.
C. high level compaction into metaphase-type chromosomes.
D. histone, DNA, and nonhistone covalent bonding.
The histone that appears to be responsible for organizing the 100 Å fibers into 300 Å fibers is
With regard to the typical human cell, which of the following appears to be true?
A. There is only one origin of replication.
B. There are multiple origins of replication that function consecutively.
C. There are multiple origins of replication that function simultaneously.
D. Replication is not understood well enough to postulate on replication origins.
In mammalian cells, replication proceeds
C. unidirectionally from many origins.
D. bidirectionally from only one origin.
What are the four major classes of chromosomal rearrangements?
A.Inversions, duplications, translocations, deletions
B.Duplications, reciprocal translocations, non-reciprocal translocations, inversions
C. Deletions, inversions, duplications, reciprocal translocations
D. Translocations, pericentric inversions, paracentric inversions, deletions
The type of chromosomal rearrangement that reorganizes the DNA sequence within one chromosome is known as a(n)
In general, which type of mutation usually has the greatest probability of lethality?
The term for when a piece of one chromosome attaches to another chromosome is
During the pairing of homologs in prophase of meiosis I, the region of a normal, non-deleted chromosome that has nothing with which to recombine forms a
A. inversion loop.
B. deletion heterozygote.
C. crossover suppressor.
D. deletion loop.
When a crossover occurs within the inversion loop of a pericentric inversion each recombinant chromatid will have
A. a dicentric bridge.
B. no duplications.
C. a deletion of some genes in the inverted region.
D. no mutations
Down syndrome can result from
A. three copies of chromosome 21.
B. a translocation of a part of chromosome 9.
C. a reciprocal translocation between any two autosomes.
D. trisomy X
Which of the following is not an example of an aneuploidy?
E. increased susceptibility to infection.
What is a typical characteristic of bacterial chromosomes?
A. 5% of the sequences encodes proteins
B. It has telomeres
C. It is linear
D. On average a gene occurs once in every 1000 bp
Penicillin stops bacterial cell wall formation by
A. inhibition of a transpeptidase
B. inhibiting synthesis of NAM.
C. inhibiting synthesis of NAG.
D. inhibiting transport of NAG and NAM past the permeable membrane.
What would happen if a transposon were to integrate into the origin of the bacteria genome?
A. Transposon would be replicated like the genome.
B. Transposon would "jump" to another locaiton
C. Transposon would inactivate the origin, no DNA replication possible.
D. Transposon would express its genes constitutively.
If an organism is isolated that has no nuclear membrane and the DNA is condensed into a body in the cytoplasm this organisms would most likely be classified as a
D. could either be a Eukaryote or Prokaryote
What is the difference between a Tn and IS element?
A. Tn elements can carry antibiotic resistance genes.
B. IS elements carry a transposase gene.
C. Tn elements integrate into plasmids and genomes.
D. IS elements integrate into plasmids and genomes.
Extranuclear genes show a biparental inheritance patter in yeast since
A. progeny from diploid vegitative growth can have the phenotype of the dominant phenotype.
B. progeny from diploid vegitative growth can have the phenotype of the α parent.
C. progeny from diploid vegitative growth can have the phenotype of only the a parent.
D. progeny from diploid vegitative growth can have the phenotype of either the a or the α parent.
Variegated four o'clock leaves have white patches among the green areas due to
A. an mtDNA mutation, which blocks electron transport.
B. a cpDNA mutation, which incapacitates proteins essential for photosynthesis.
C. a nuclear DNA mutation, which leads to mosaicism.
D. both cpDNA mutation which incapacitates proteins essential for photosynthesis and nuclear DNA mutation, which leads to mosaicism.
A homoplasmic cell carries
A. a mixture of organelle genomes.
B. only one type of organelle DNA.
C. only one mitochondrion.
D. two identical nuclei.
Inhibitors of bacterial translation, such as chloramphenicol and erythromycin, generally
A. are inhibitors of eukaryotic cytoplasmic protein synthesis.
B. are inhibitors of mitochondrial protein synthesis.
C. have no effect on mitochondrial protein synthesis.
D. are inhibitors of eukaryotic cytoplasmic protein synthesis and have no effect on mitochondrial protein synthesis.
What are characteristics of the pedigrees of families with mitochondrial diseases?
A. All children of affected mothers are also affected regardless of gender.
B. Only the male children of affected mothers are affected, female children are not affected.
C. Only female children of affected mothers are also affectedmales are not afected.
D. All children of affected males are also affected.