Exam 2 Flashcards
(34 cards)
Heterochromatin is ______
A) chromatin that contains a mixture of histones
B) All the other choices are correct
C) only found at centromeres
D) less condensed, transcriptionally active chromatin
E) highly condensed, transcriptionally inactive chromatin
E) highly condensed, transcriptionally inactive chromatin
Which expectation value or E value listed below would be the strongest evidence that a top hit found in
a similarity search to a query gene sequence is a homolog of the query gene?
A) 100
B) 1.0e4
C) -10
D) 1.0e-80
E) 1.0e10
D) 1.0e-80
Determine the similarity score for the alignment between these two sequences using 1 for match, -2 for
mismatch and -5 for a gap.
A - C G T A A T G
A T C G T C A T G
A) -9
B) 1
C) -5
D) 0
E) -3
D) 0
Fill in the blanks. One major type of molecule that is transported out of the nucleus is ________ and
one major type of molecule that is transported into the nucleus is _________
A) processed mRNA, proteins
B) unprocessed mRNA, processed mRNA
C) proteins, DNA
D) DNA, processed mRNA
E) proteins, unprocessed mRNA
A) processed mRNA, proteins
Which of the following statements is false about pyrimidine dimers?
A) They can be repaired by photoreactivation mediated by photolyases in all types of organisms
including humans.
B) They are lesions in DNA caused by UV radiation.
C) They are formed between adjacent pyrimidines on a DNA strand.
D) Their formation blocks DNA replication and transcription using the strand with the pyrimidine
dimers
A) They can be repaired by photoreactivation mediated by photolyases in all types of organisms
including humans.
Which of the following statements is true about the relationship between the sequences from organism
A-E predicted by the phylogenetic tree generated by comparing sequence data?
A) C and E show no similarity
B) B and E would be the least similar
C) D and E would be the least similar
D) B and C would be the most similar
E) A and E would be the most similar
D) B and C would be the most similar
Fill in the blanks in order to use the terms correctly to describe the relationship between two genes.
The genes Xyz and Abc are _______ because 90% _______ was observed in a sequence alignment
between the DNA sequences for the two genes.
A) identical, similarity
B) similar, homology
C) likely homologous, identity
D) likely homologous, homology
E) identical, homology
C) likely homologous, identity
Which of the following is a description of the nucleolus?
A) It is a region within the nucleus where rRNAs are synthesized, processed and assembled into ribosomal subunits.
B) It is the spots in the nuclear envelope through which proteins and RNA are transported.
C) It is a membrane bound compartment within the nucleus
D) It is the site on chromosomes where microtubules attach to mediate chromosome segregation.
E) It is a region within the nucleus where introns are spliced out of mRNA.
A) It is a region within the nucleus where rRNAs are synthesized, processed and assembled into
ribosomal subunits.
Which of the following is a conservative substitution in an alignment of two protein sequences?
A) A purine base aligned with different purine base in a nucleotide sequence alignment
B) A nonpolar amino acid aligned with a different nonpolar amino acid in an alignment of two
protein sequences
C) A deoxyribonucleotide aligned with a ribonucleotide in a nucleotide sequence alignment
D) A polar amino acid aligned with a nonpolar amino acid in an alignment of two protein sequence
B) A nonpolar amino acid aligned with a different nonpolar amino acid in an alignment of two
protein sequences
Which of the following is NOT true about the shotgun method of genomic DNA sequencing?
A) Involves the creation of bacterial artificial chromosomes with large peices of the genome
B) Uses overlaps between different reads to assemble the DNA sequence of each chromosome
C) Involves the creation of thousands of small pieces of the genome
D) Is currently the usual method used for genomic sequencing projects
A) Involves the creation of bacterial artificial chromosomes with large peices of the genome
You are analyzing the newly sequenced genome of the organism Drosophila nebraski and discover the
presence of multiple similar DNA sequences that appear to be genes that encode similar proteins.
These sequences would be called _______.
A) SINEs
B) Pseudogenes
C) A gene family
D) Single sequence repeats
E) Introns
C) A gene family
Reverse transcriptase plays a role in generating additional copies of all of the following DNA elements
EXCEPT ______?
A) Centromeres
B) Retrotransposons
C) SINES
D) Retroviruses
E) LINES
A) Centromeres
The percentage of the human genome that codes for proteins (protein-coding) is about ______
A) 25%.
B) 10%.
C) 45%
D) 90%.
E) 1.2%.
E) 1.2%.
The principal element providing structural support for the shape of the nucleus is _________
A) the chromatin scaffolding proteins for each chromosome
B) a meshwork of microtubules attached to the cytoplasmic face of nuclear envelope
C) a meshwork of branched polysaccharide chains located in the perinuclear space
D) a meshwork of straight polysaccharide chains attached to the exterior surface of the nuclear
envelope
E) a meshwork of intermediate filaments attached to the interior face of the nuclear envelope
E) a meshwork of intermediate filaments attached to the interior face of the nuclear envelope
What protein acts to help coordinate the replication of both strands by binding to each of the
polymerases acting on each strand and other proteins involved in replication?
A) Helicase
B) DNA ligase
C) Primase
D) Clamp loading protein
D) Clamp loading protein
Which of the following would be the top hit if one was doing a search for sequences similar to the
sequence TAGAATGC?
A) TAGTATGG
B) TCCAATTC
C) T-GAA-GC
D) TC-AATAG
A) TAGTATGG
The nuclear localization signal is recognized by and binds to which protein in the process of nuclear
protein import?
A) Exportin
B) The outer fibril protein
C) Importin
D) Ran
C) Importin
Which of the following describes the role of histones in cells?
A) They act to unwind the two strands of DNA during replication.
B) They are proteins that bind to telomeres and help to add more telomeres to chromosomes.
C) They are only found in the regions of chromosomes that are heterochromatin and they help to
make those areas heterochomatin.
D) They form the protein scaffold of a chromosome to which large loops of DNA are attached.
E) They form a complex of eight proteins and two loops of DNA wrap around the complex to help
pack the DNA inside cells.
E) They form a complex of eight proteins and two loops of DNA wrap around the complex to help
pack the DNA inside cells.
The BLAST algorithm of the National Center for Biotechnology Institute (NCBI) and the hits or results
of its use can be used for which of the following?
A) Finding protein sequences in the database that are similar to a query protein sequence.
B) Creating a phylogenetic tree based on selected similar sequences.
C) Creating a multiple sequence alignment comparing sequences similar to a query nucleotide or
amino acid sequence.
D) All the other choices are correct
E) Finding nucleotide sequences in the database that are similar to a query nucleotide sequence.
D) All the other choices are correct
Which of the following describes how nuclear proteins (proteins that act in the nucleus) move into the
nucleus?
A) Each nuclear protein binds to the nuclear pore which then cleaves ATP which causes the nuclear
pore to open so that the nuclear protein can enter the nucleus.
B) Each nuclear protein is bound by a transport protein that carries the nuclear cargo protein through
a nuclear pore into the nucleus. The transporter protein cleaves ATP as it enters the nucleus.
C) Nuclear proteins diffuse into the nucleus by simple diffusion through the nuclear pore (No energy
input is needed)
D) Proteins are pumped into the nucleus by ribosomes as they are being synthesized
E) Each nuclear protein is bound by a transporter protein which carries the nuclear protein through a
nuclear pore into the nucleus. The nuclear protein is released in the nucleus when a G protein with
GTP interacts with the transporter protein. The G protein then carries the transport protein out of
the nucleus. On the cytosolic side of the pore, the G protein cleaves its bound GTP and then
releases in the transporter protein.
E) Each nuclear protein is bound by a transporter protein which carries the nuclear protein through a
nuclear pore into the nucleus. The nuclear protein is released in the nucleus when a G protein with
GTP interacts with the transporter protein. The G protein then carries the transport protein out of
the nucleus. On the cytosolic side of the pore, the G protein cleaves its bound GTP and then
releases in the transporter protein.
Which of the following statements is true of all known DNA polymerases?
A) They synthesize DNA in the 3 to 5 direction, and they possess exonuclease activity.
B) They synthesize DNA in the 5 to 3 direction, and they require a preformed primer hydrogenbonded to the template.
C) They synthesize DNA in the 5 to 3 direction, and they possess primase activity.
D) They require a preformed primer, and they possess helicase activity.
B) They synthesize DNA in the 5 to 3 direction, and they require a preformed primer hydrogenbonded to the template.
Written below is a citation information for a journal article that came up in a search using PubMed.
Which of the following is true?
Identification and characterization of SpcU, a chaperone required for efficient secretion of the ExoU
cytotoxin.
Finck-Barbançon V, Yahr TL, Frank DW.
J Bacteriol. 1998 Dec;180(23):6224-31. doi: 10.1128/JB.180.23.6224-6231.1998.
PMID: 9829931 Free PMC article.
A) A digital object identifier was not shown for this article.
B) The name of the journal in which the article was published is J Bacteriol.
C) The article is not freely available.
D) The first author is Frank DW
E) The article was published in 2023
B) The name of the journal in which the article was published is J Bacteriol.
Most alterations of bases or nucleotides are mutagenic. Which of the following is an type of alteration
or modification of nucleotides in DNA that is NOT mutagenic and is done by cells on purpose?
A) Modification of a base by a hydroxyl radial or oxygen radical
B) Some types of methylation of cytosine (C) or adenine (A) bases
C) Depurination or loss of a purine base
D) Deamination of a cytosine base which causes it to become uracil
E) Formation of a pyrimidine dimer
B) Some types of methylation of cytosine (C) or adenine (A) bases
Homologous recombination plays a role in repairing which of the following types of alterations of or
damages to DNA?
A) Thymine dimers
B) Alkylation
C) Deamination
D) Depurination
E) Double strand break
E) Double strand break
