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573 Cards in this Set
- Front
- Back
Biosynthesis of RN Which of following statements describes a difference between replication of DNAand transcription of RNA? |
Both strands of DNA are copied in replication, but usuallyonly one is copied in transcription. |
|
Biosynthesis of 2 Which of following statements concerning RNA transcription is false? |
Synthesis of RNA is as accurate as synthesis of DNA |
|
Biosynthesis of 3 Which of following statements concerning RNA transcription is false? |
Transcription requires the use of a primer. |
|
Biosynthesis of 4 The enzyme principally responsible for RNA synthesis in Escherichia coli |
is a multisubunit enzyme |
|
Biosynthesis of 5 The end of the new mRNA molecule in E.coli. usually terminates in a string of A's |
False |
|
Biosynthesis of 6 Which of the following correctly describes a difference between RNA & DNApolymerases? |
DNA polymerases usually require a primer (i.e., they can onlycontinue a strand, not start one), while most RNA polymerases do not. |
|
How do the core enzyme and the holoenzyme of RNA polymerase differ in E. coli? |
The holoenzyme includes the sigma (s) subunit, the coreenzyme does not. |
|
Which of these terms does not describe the DNA strand used to direct RNA synthesis? |
Coding strand |
|
At what point does the sigma (s) subunit of RNA polymerasereleased from the core enzyme? |
After transcription begins and about 10 nucleotides have been added to the RNA chain. |
|
RNA synthesis begins at the base in the DNA sequence designated by the following number: |
+1 (plus one) |
|
What is the function of the sigma (s) subunit of RNA polymerase in E. coli? |
It recognizes promoters where transcription should begin. |
|
Which of the following is not a property of the sigma (s) subunit? |
It stays with the RNA Pol throughout synthesis. |
|
Which of the following is not part of the core promoter? |
the UP element |
|
The promoter site is |
the site on DNA at which RNA polymerase binds to initiate transcription |
|
Which of the following offers the best description of aPribnow box? |
A promoter consensus sequence located at approximately -10. |
|
Initiation of RNA biosynthesis involves |
conversion of the closed-promoter complex to the open-promoter complex |
|
Consensus sequences are |
sequences that have many bases in common |
|
What provides the energy for rho-dependent chain termination? |
ATP hydrolysis distinct from any incorporation into thechain. |
|
Minor differences in the consensus sequence for RNA Polymerase |
can be exploited to vary the amount of mRNA which is synthesized from that gene. |
|
Which of the following best describes the order of events at the promoter? |
closed complex ® open complex ® transcription initiation |
|
What provides the energy for the conversion from the open complex to chain elongation? |
Torsional stress built into the separating DNA strands. |
|
Chain termination occurs, invivo, when: |
Either a hairpin loop forms or rho (r) is involved. |
|
In prokaryotic RNA synthesis |
inverted-repeat sequences in the DNA being transcribed canlead to termination |
|
What is the need for a primer strand in transcription? |
There is none. |
|
Which is not associated with bacterial promoters? |
3' antiterminator |
|
Which of the following is true concerning the firstnucleotide incorporated into an RNA chain? |
The first nucleotide incorporated into the RNA chain retainsits 5'-triphosphate |
|
The weakness of A-U base pairs at the end of the RNA moleculemay help in dissociation of the new RNA product. |
True |
|
There is only one sigma subunit, since the same RNA Polymerase must bind to all genes in E.coli. |
False |
|
How do enhancers differ from promoters? |
Enhancers do not bind RNA polymerase. |
|
Which of the following is the best description of an operon? |
A group of genes under the control of a common promoter. |
|
Operons |
are subject to positive or to negative control. |
|
Which of the following influence the amount of expression of an operon? |
Availability of the specific sigma factor for that operon.b. Howwell the Pribnow box conforms to the consensus sequence.c.Attenuation mechanisms.d.Presence of 3' 5' cyclic AMP.*e. All ofthese. |
|
Which of the following doesnot influence the timingof expression of an operon? |
Repressors |
|
A mutation in the lac A gene would result in |
normal operation of the lac operon, but with an alteration inthe proteins encoded by the lac A gene |
|
Cyclic AMP affects transcription by |
triggering the action of several protein factors |
|
A single operon |
usually contains all the enzymes which are specific for thesynthesis of a special biomolecule. |
|
All of the following apply to attenuation mechanisms, except: |
The rate of RNA synthesis is regulated by the conformation ofthe protein being synthesized. |
|
Which of the conditions would result in the greatest amount of transcription of thelac operon? |
IV low high |
|
Attenuation mechanisms rely on alternative secondarystructures forming in the mRNA. |
True |
|
Which of the following is not a characteristic of catabolite activator protein (CAP)? |
the binding of CAP to DNA requires ATP hydrolysis |
|
Which of the conditions would result in the least amount of transcription of the lac operon? |
high low |
|
Control of transcription in prokaryotes does not involve |
leucine zipper proteins |
|
Inducers for operons are often structurally related to theenzyme substrates of that operon. |
True |
|
Inducers allow for a system in which an enzyme is not madeunless it is needed. |
True |
|
The catabolite activator protein can overcome the effect of arepressor binding to the operon. |
True |
|
Which of the following is true about riboswitches: |
They have a molecule sensing domain called an aptamerb. Thereare known pathogens that use riboswitches as part of their mechanismc. Theyrespond to specific molecules and control translation in a way that is oftensimilar to transcription attenuationd. Theycontain a sensing domain and a decision making domain*e. All ofthese |
|
Which of the following statements about eukaryotic andprokaryotic RNA polymerases, is false? |
Eukaryotic polymerases have the same number of subunits asprokaryotic ones. |
|
Which enzyme transcribes genes encoding tRNA in eukaryotes? |
RNA polymerase III |
|
Which of the following isnot a key step in the activation of mRNA synthesis in eukaryotes? |
Binding of RNA Pol I. |
|
Which of the following statements about the various RNAPolymerases in eukaryotes is false? |
Eukaryotic RNA polymerases are generally monomeric. |
|
How do eukaryotic and prokaryotic RNA polymerases compare? |
Despite their added complexity, eukaryotic and prokaryoticRNA polymerases are generally homologous. |
|
Where is the TATA box located? |
-25 region. |
|
TATA-binding protein (TBP) is required for transcription by |
Pol I.b. Pol II.c. PolIII.*d. all ofthese polymerases |
|
Phosphorylation of the CTD of RNA polymerase II occurs duringwhich phase of transcription? |
conversion from the closed complex to the open complex |
|
Transcription in eukaryotes differs from RNA synthesis inprokaryotes |
by having multiple RNA polymerases rather than one. |
|
RNA polymerases from prokaryotes and eukaryotes |
have sequence homology in catalytic subunits |
|
A transcription factor is |
a protein other than RNA polymerase that is involved intranscription. |
|
Initiation of transcription in eukaryotes is primarilycontrolled |
in the formation of the preinitiation complex |
|
The eukaryotic TATA-binding protein (TBP) functions in amanner similar to |
sigma (s) factor in E.coli. |
|
Which of the following transcription factors is involved inthe elongation phase of eukaryotic transcription? |
TFIIF |
|
The elongation and termination phases of eukaryotictranscription |
require several protein factors |
|
Which of the following is not true? |
RNA Pol IV is the primary RNA synthesizer in plants |
|
The major difference between RNA initiation in eukaryotes andprokaryotes is the number of factors involved in the process. |
True
|
|
One rather unusual transcription factor in eukaryotes haltsRNA synthesis to allow for repair of damaged DNA. |
True |
|
Response elements |
are enhancers of transcription activated by metabolic factors |
|
As in prokaryotes, the regulatory regions for eukaryoticgenes: |
may be close to the genes they controlb. may beupstream of the genes they controlc. may bedownstream of the genes they control*d. All ofthese are true |
|
Intracellular levels of cyclic AMP can affect thephosphorylation of proteins and enzymes as a secondary messenger. |
True |
|
RNA transcribed from the coding strand instead of thetemplate strand |
is called antisense RNA. |
|
Proteins that recognize DNA with specific base sequences are |
more likely to bind to the major groove. |
|
The leucine zipper is different from other DNA bindingdomains, since it requires the DNA-binding protein to form a dimer. |
False |
|
DNA binding domains are distinct from transcription-activationdomains. |
True |
|
Which of the following is not a structural motif encounteredin DNA-binding proteins? |
b-barrel |
|
CREB contains the following structural motif: |
Leucine zipper |
|
Which of the following best describes leucine zipper motifs? |
They allow protein-protein interactions via hydrophobicbonds. |
|
Which of the following isnot a common modification occurring after polymerization of RNA? |
Addition of phosphate to the bases. |
|
Alternative removal of exons from mRNA is important in whichof the following? |
Troponins and other contractile proteins.b.Different types of collagen.c. Thedisease lupus.d.Alzheimer's disease.*e. All ofthese. |
|
Capping of eukaryotic mRNA |
occurs at the 5' end. |
|
Polyadenylation of eukaryotic mRNA |
occurs at the 3' end. |
|
Which of the following RNAs is noted for having a"cloverleaf" structure? |
tRNA |
|
In eukaryotes, which of the following types of RNA undergosome base modification after polymerization of the monomers? |
mRNAb. tRNAc. rRNAd. mRNAand tRNAe. mRNAand rRNA*f. all ofthese |
|
The sequences in eukaryotic DNA known as introns are |
the intervening sequences not expressed in the final sequenceof messenger RNA |
|
A commonly encountered feature of transfer RNA synthesis is |
the precursor of several tRNA molecules is transcribed in onelong polynucleotide sequence |
|
Post-transcription processing of mRNA in prokaryotes isrequired. |
False |
|
The lariat mechanism has been demonstrated by observing thelariat structure using electron microscopy. |
True |
|
Alternative splicing of exons is a mechanism to get more than1 protein from the same gene. |
True |
|
Which ends of eukaryotic mRNA are protected from degradation? |
Both ends |
|
Which ends of prokaryotic mRNA are protected fromdegradation? |
Neither end |
|
Splicing reactions for exons involve the followingmechanisms, except: |
Small nuclear RNAsb.Ribozymesc. Lariatmechanismsd.Participation of special G residues*e. All ofthese are involved in splicing reactions |
|
Ribozymes, the catalytic activity of RNA, were firstdiscovered as part of the snRNA group. |
True |
|
Which category of ribozymes requires an external guanosinefrothier action? |
Group I |
|
Ribozymes |
are involved in protein synthesis |
|
Which of the following is true about micro RNAs? |
They are a type of non-coding RNA |
|
Non-coding RNAs are known to: |
. bind to mRNA targeting them for destructionb. bind tomRNA preventing their translationc. promoteRNA silencing*d. all ofthese |
|
Chpt 12 |
Chpt 12 |
|
Which category of RNA carries amino acids for the process oftranslation? |
tRNA |
|
The majority of protein synthesis occurs in the |
cytoplasm |
|
As in RNA and DNA synthesis, the synthesis of proteinsfollows the following steps, except: |
Activation of monomersb.Initiationc.Elongationd.Termination*e. All ofthese are involved in all polymer synthesis |
|
The template for protein synthesis is: |
a mRNA strand |
|
Which of the following statements concerning the genetic codeis false? |
. Commas are used. |
|
Wobble allows each codon to interact with more than one tRNA. |
True |
|
Which of the following isnot an advantage of degeneracy in the genetic code? |
More than one amino acid can bind to a tRNA. |
|
Inosine or hypoxanthine can wobble with all the followingbases, except: |
. Ab. Cc. Td. U*e.Inosine can wobble with all of these bases. |
|
Which of the following codons does not code for an amino acid? |
UAA |
|
Wobble allows a single codon to code for more than one aminoacid. |
False |
|
At which position on tRNA is the wobble base of the tripletanticodon? |
1st position (5' letter) |
|
Whattype of assay using tRNAs and ribosomes enabled complete determination of thegenetic code? |
filter binding assays |
|
Which of the following isnot a key advantage of wobble in the codon-anticodon reaction? |
It allows for making more than one protein from the samecoding sequence. |
|
Transfer RNAs contain an anti-codon loop meant to match (basepair) with a codon on an mRNA. |
True |
|
In the wobble phenomenon, the base that wobbles is found in |
the tRNA. |
|
How many codons are known for each amino acid? |
1 to 6 depending on the nature of the amino acid |
|
Exceptions to the universality of the genetic code have beenobserved in |
mitochondria and 16 other organisms, including some algae andfungae |
|
What is the maximum number of amino acids that can bespecified by a codon consisting of a sequence of two bases? |
16 |
|
Which amino acids have unique codons? |
trp, met |
|
How many codons are possible in a system in which a sequenceof three bases specifies a single amino acid? |
64 |
|
A tRNA was determined to have the following anticodonsequence:3'-GAI-5' (I represents the base hypoxanthine)Which of the following codons can form base pairs with this anticodon? |
5'-CUA-3'b.5'-CUC-3'c.5'-CUU-3'*d. all ofthese |
|
Using the genetic code, indicate which polypeptides would besynthesized if poly (UGG) were used as a synthetic mRNA? |
poly(trp), poly(val), poly(gly) |
|
The genetic code is said to be degenerate. This means that |
many of the amino acids are coded for by different codons. |
|
The process of amino acid activation |
involves the formation of an ester bond between the aminoacid and tRNA |
|
The initial step in the formation of an aminoacyl-tRNA is |
activation of the amino acid by reaction with ATP |
|
An aminoacyl-adenylate contains |
an acid anhydride bond |
|
Which of the following statements concerning tRNAs is false? |
They are unique in that they are transcribed by DNApolymerases |
|
Which of the following is not true? |
aminoacyl-tRNA synthetases link amino acids to tRNAmolecules without the need for an energy source |
|
Which of following best describes the two-step process foradding amino acids to tRNAs? |
AA + ATP ® AA-AMP + PPi; AA-AMP + tRNA ® AA-tRNA + AMP |
|
Activation of amino acids always takes place |
in the cytoplasm |
|
Which linkage best describes the covalent bond between anamino acid (AA) and its tRNA? |
Carboxyl group of AA linked to 3' -OH of tRNA. |
|
Amino acids linked to the 2'-end of a tRNA |
are transferred to the 3' position prior to their use inprotein synthesis |
|
Thestandard free energy change for the following reaction is about zero.amino acid + ATP + tRNA ® aminoacyl-tRNA + AMP + PPiThe driving force for this reaction in the cell is |
the subsequent hydrolysis of pyrophosphate releases energy |
|
Activation of amino acids |
produces a pyrophosphate byproduct. |
|
The amino acids are initially attached to either the 2' or 3'hydroxyl group of the tRNA. |
True |
|
Specificity of aminoacyl-tRNA synthetases is always based onthe anticodon. |
False |
|
The activating enzymes can actually remove wrong amino acidsattached to a tRNA. |
True |
|
Each tRNA molecule has a separate activating enzyme. |
False |
|
Which of the following isnot a function of elongation factors in E.coli? |
Keep the ribosomal subunits bound together. |
|
The tRNAs may bind to the standard stop codons |
in cellular organelles which use a modified genetic code.b. toaccommodate the tRNA for the unusual amino acid selenocysteine.c. whenthe anticodon in a tRNA mutates to a sequence which can bind.*d. All ofthese |
|
Which antibiotic confirmed that the growing peptide chain istransferred to the amino group of the incoming tRNA? |
Puromycin |
|
In bacteria, each mRNA will bind to only one ribosome at atime. |
False |
|
The mRNA must contain the following to allow for initiationof protein synthesis in E. coli. |
A Shine-Delgarno sequence. |
|
Which of the following is not required for the elongationphase of protein synthesis? |
fmet-tRNAfmet |
|
Which of the following isnot a function of termination factors in E. coli? |
Cause the ribosomal subunits to dissociate. |
|
Which of the following isnot a function of initiation factors in E.coli? |
Lead the initial tRNA to its correct position on the largesubunit of the ribosome. |
|
An aminoacyl-tRNA is initially bound to the ribosome |
at the A site on the 50S subunit |
|
After peptide bond formation takes place, what step isnecessary for continuation of protein synthesis? |
translocation of the ribosome |
|
In protein synthesis formation of new peptide bonds iscatalyzed by |
peptidyl transferase |
|
What is the mode of action of puromycin in the inhibition ofprotein synthesis? |
termination of the growing polypeptide chain |
|
The match between codon and anticodon is one of the manyproofreading aspects of protein synthesis. |
True |
|
At what point does the formylation reaction take place toproduce N-formylmethionine? |
After methionine has been added to a specific tRNA. |
|
N-formyl methionine |
can be found attached to some proteins in E. coli. |
|
What is the start codon on the mRNA for prokaryotictranslation? |
AUG |
|
The formylation of methionine in prokaryotes |
depends on two different tRNAs, where methionine can beformylated when bound to one form and not the other. |
|
Which of the following is not a prokaryotic elongationfactor? |
EF-Ts |
|
What happens when a stop codon is reached by a ribosome (inthe A site)? |
A termination protein binds to the codon and is used torelease the growing peptide from the P site tRNA. The ribosome then is likelyto dissociate. |
|
Which of the following best describes the assembly process toinitiate translation in prokaryotes? |
. small subunit associates with mRNA; IF w/ bound NTP bringsin first f-Met-tRNA; IF then hydrolyses bound NTP; large subunit associates |
|
Which of the following is necessary for chain termination inprotein synthesis? |
termination codons of mRNAb. releasefactorsc. GTP*d. all ofthese |
|
A polysome is |
a complex consisting of one mRNA to which several ribosomesare attached |
|
The ribosome is actually a ribozyme. |
True |
|
In bacteria, translation of the mRNA begins |
during the synthesis of the mRNA. |
|
A Shine-Dalgarno Sequence is a |
sequence of nucleotides in an mRNA that interacts with thesmall subunit of a ribosome to begin translation. |
|
Protein synthesis in prokaryotes always starts with |
a formylmethionine residue |
|
During elongation, tRNA binds initially to the |
"A" site on the ribosome. |
|
The first tRNA (bearing fmet) binds to the |
"P" site on the ribosome. |
|
Under certain conditions, tRNAs can bind to the standard stopcodons. |
True |
|
How do eukaryotic and prokaryotic translation compare? |
Eukaryotes utilize very different protein factors during theprocess but the ribosomes are homologous. |
|
The actual functions of the factors in eukaryotes are similarto the functions of these factors in bacteria. |
True |
|
The final form of mRNA in eukaryotes has all these features, except: |
The mature, active mRNA contains introns. |
|
How do eukaryotic ribosomes prevent false starts atinappropriate parts of the mRNA? |
There is a consensus sequence, called the Kozak sequence,surrounding the start codon in eukaryotes. |
|
Which of the following is true concerning protein synthesisand memory? |
Inhibition of protein synthesis in eukaryotes leads to lackof long term memory |
|
Which of the following is associated with post-translationalprocessing of proteins? |
Folding into the 3-dimensional shapeb.Breaking large proteins into several components with differing functionsc. Formingdisulfide bondsd.Modification of specific amino acids*e. All ofthese |
|
Leader sequences for protein transport to specific organellesare removed by proteases associated with the: |
endoplasmic reticulum |
|
Chaperones assist in protein folding by preventingaggregation of proteins before folding is completed. |
True |
|
There is no codon for the amino acid hydroxyproline, but thisamino acid is a prominent feature of collagen structure. Which of the followingis a likely explanation? |
Proline is covalently modified to give hydroxyproline aftertranslation. |
|
Degradation of proteins |
frequently makes use of proteasomes |
|
The protein which marks proteins for degradation is called: |
Ubiquitin |
|
Which of the following is not true concerning silent mutations? |
Only changes in base sequence that lead to a different aminoacid can have an effect on the organism |
|
HIF-1 is related to which process? |
How we adapt to high altitude |
|
Chpt 13 |
Chpt 13 |
|
Which of the following best describes electrophoretic gelsused for DNA? |
Most separations are done horizontally, while sequencing gelsare typically run vertically. |
|
Migration of DNA during electrophoresis is based. |
mostly on the size of the molecule, since the ratio of chargeto mass is approximately the same, no matter how large the DNA is. |
|
The application of gel electrophoresis (PAGE) in DNAsequencing |
depends on separation of similar charge/mass ratio on thebasis of size. |
|
Which of the following parameters affects the distance DNAmolecules migrate during electrophoresis, at pH = 8? |
The mass of the DNAb. Thetotal ionic charge on the DNA moleculec. Thefact that each nucleotide contributes one negative charge at this pH.d. Theconcentration of agarose or polyacrylamide in the gel.*e. All ofthese features control the distance the DNA migrates. |
|
Ethidium bromide slips between the bases of DNA giving itfluorescent properties that differ from those observed when it is free insolution. |
True |
|
Fluorescence works because the fluorescent molecule |
absorbs light at one wavelength and emits light at a longerwavelength. |
|
When fluorescence detection methods are used in biotechnologythey |
do not present the hazards associated with radioactivity |
|
A highly useful method for determining the presence ofhydrolyzed fragments of DNA separated by electrophoresis is |
autoradiography |
|
Fluorescent techniques can detect concentrations as low as |
picomolar (10-12 M). |
|
Which of the following are methods used to determine wherethe DNA bands are located on an electrophoresis gel? |
a. Radioactivityb.Fluorescencec. Dyeswhich bind to DNAd.Luminescence*e. All ofthese can visualize the DNA |
|
Fluorescence and other luminescent methods of visualizing bandsoffer these advantages over methods dependent on radioactivity. |
These methods are both more sensitive and require no speciallicense. |
|
SyBr green and SyBr gold were developed because |
ethidium bromide is carcinogenic |
|
Restrictionenzymes are especially useful for genetic recombination work for all of thefollowing reasons, except: |
They cut DNA in the middle of specific sequences.b. Theycut DNA independent of the source of the DNA.c. Theyoften generate single stranded tails or "sticky ends".d. Thereare a large variety of them commercially available.*e. All ofthese traits make restriction enzymes useful. |
|
The "natural" function of restriction endonucleasesis to |
protect bacterial cells from invasion by viruses(bacteriophages). |
|
Which of the following statements concerning restrictionendonucleases is true? |
They can produce "sticky ends". |
|
A palindrome is |
a sequence that reads the same from left to right or fromright to left |
|
An isoschizomer is a(n) |
a restriction enzyme that has the same sequence specificityas another restriction enzyme from a different organism |
|
A single clone of interest can be distinguished from othersin a mixture of clones by |
a specific probe, usually a labeled complementary DNA. |
|
Enzymes that seal nicks in DNA are called |
ligases. |
|
A plasmid is |
a small circular DNA that is not part of a bacterialchromosome. |
|
Recombinant DNA molecules contain covalently linked segmentsderived from two or more sources. |
True |
|
The following steps are all involved in geneticrecombination: |
4 ® 2 ® 3 ® 5 ® 1 |
|
Which of the following are methods by which bacteria can beinduced to take up recombinant DNA molecules? |
a. Heat shock.b. DNA"guns" which spray the DNA at very high speeds.c.Electroporationd. Phageor virus infection.*e. All ofthese are used to transform bacteria. |
|
Multi-cloning sites ("poly-linkers") in mostcommercially available plasmids offer all the following advantages over theearlier plasmids used in genetic recombination except: |
They assure that only the desired DNA will be inserted intothe plasmid. |
|
In recombinant DNA technology |
a. vectors are used as carriers for recombinant genes.b. it ispossible to insert eukaryotic genes into prokaryotic DNA.c. foreignDNA is frequently inserted into a bacterial plasmid.*d. all ofthese |
|
The presence of bacterial or viral clones is detectedexperimentally by |
the presence of colonies or plaques on a suitably preparedPetri dish. |
|
Suitable vectors for cloning of recombinant DNA can be |
both of these |
|
Which of the following isnot required in order for a plasmid to be used in genetic recombination? |
A poly-cloning site or multi-cloning site for gene insertion. |
|
Cells that contain a "blue/white screening" plasmidthat has an added gene are recognized by the method: |
The colonies lack a blue color. |
|
During the simplest type of genetic recombination, there is a____ chance that the gene will be inserted in the correct direction. |
50% |
|
Recombined bacteriophage particles are easy to isolate, sincehigh concentration of phage will be found in each of the bacterial coloniesthat grow on the medium used for screening. |
False |
|
DNA into the BamHIsite, the recombinant plasmid would lackwhich of the following properties? |
It would be resistant to the antibiotic tetracycline. |
|
If a recombinant plasmid were obtained by inserting DNA intothe EcoRV site, and the proteincorresponding to the recombinant gene were expressed, which of the followingstatements would be false? |
The plasmid will not be able to replicate autonomously. |
|
DNA into the AflIIIsite, the recombinant plasmid would lackwhich of the following properties? |
It can replicate autonomously. |
|
DNA into the BamHIsite, screening for the recombinant plasmid can be done by the followingtechnique. |
Plate on nutrient agar plates that contain ampicillin,followed by replica plating on tetracycline. |
|
If the region between the 2 sites for HgiEII were deleted, the resulting plasmid |
would be useless as it would lack an origin of replication. |
|
If the plasmid were completely digested with the tworestriction enzymes BamHI and HgiEII, the resulting fragments would bethis large: |
1920, 1682 and 761 base pairs long. |
|
Antibiotic-resistance genes in vectors are often used asselectable markers. |
True |
|
A multiple clonic site is also known as: |
a polylinker |
|
DNA fragment for analysis? |
HindIII |
|
Neglecting any discussion of whether it's a good or badchoice, I attempt to insert a gene fragment into the HindIII site and transform bacteria with the plasmid. How can Itell which transformants have the insert? |
The bacteria will be able to grow in the presence ofampicillin, and they will be white. |
|
When viruses are used as vectors in gene therapy |
they can cause unexpected difficulties |
|
Genetic engineering which recombines DNA from differentspecies is |
. a molecular extension of traditional cross-breedingmethods. |
|
How is human insulin produced by genetically engineeredbacteria? |
DNA that codes for each of the two polypeptide chains isintroduced into two different populations of bacteria |
|
Genetic recombination occurs in nature. |
True |
|
How does an expression vector differ from a regular cloningvector? |
An expression vector has the ability to have the inserted DNAbe transcribed. |
|
Which of the following plants have been genetically modified? |
a. Soybeansb. Corn.c. Cottond.Tomatoes*e. All ofthese plants have been genetically modified. |
|
In gene therapy |
cells of specific tissues are altered in a way thatalleviates the effects of a disease. |
|
While a large majority of people are opposed to somatic genetherapy, a large number support the use of germ-cell gene therapy. |
False |
|
One major obstacle to using bacteria to produce humanproteins is because addition of sugar residues to the proteins, glycosylation,never occurs properly. |
True |
|
One major obstacle to using bacteria to produce humanproteins is bacteria do not have the cellular apparatus to splice introns outof mRNA. |
True |
|
Which of the following proteins has been successfullyproduced through genetic recombination? |
a. insulinb. humangrowth hormonec. tissueplasminogen activatord.erythropoietin*e. All ofthe above proteins have been produced successfully. |
|
Which of the following isnot a potential benefit of creating a fusion protein in geneticengineering? |
. The protein is less likely to be antigenic. |
|
Genetic engineering |
a. is being used to produce improved crop plants.b. mayprovide therapy for diseases of genetic origin. |
|
Which of the following statements about plants which containthe recombinant form of the gene from Bacillusthuringiensis (Bt gene), is true? |
a. These plants have a natural resistance to caterpillars.b. Thegene is expressed in all the plant tissues.c. Sincethe gene is expressed in the pollen of the plant, there is concern about thegene harming beneficial insects.d. It islikely that some insects will mutate to become resistant to the Bt geneproduct.*e. All ofthese statements are true. |
|
Which of the following conditions is an example of howgenetic engineering is currently used to increase food production? |
a. Genetically modified plants have been developed that areresistant to herbicides.b.Genetically modified plants have been developed which contain a gene thatconfers a natural resistance to certain insects.c.Hormones are given to cows to increase milk production.d.Genetically modified plants have been developed which are resistant to frost.*e. All ofthese are examples of genetic engineering in agriculture. |
|
Modern genetic engineering allows the following manipulation,which was not available using traditional breeding methods: |
It is now possible to include genes from different species,or even different kingdoms in the same organism. |
|
Which of the following conditions is not a requirement to assure production of a protein when aplasmid is being designed to express a eukaryotic protein in a bacterium? |
Differences in the genetic code between eukaryotes andprokaryotes must be accommodated. |
|
Which of the following proteins are produced by recombinantDNA technology but have had their purposes subverted for improving athleticperforrmance? |
. Erythropoietin and Human Growth Hormone |
|
A gene from Bacillusthuringiensis (Bt) is used to make plants resistant against all insectswhich might feed on the plant. |
False |
|
The use of the Bt gene is prohibited in corn plants. |
False |
|
Sometimes DNA probes are used to prove that a gene has beenincorporated into a eukaryotic genome. The following are all steps used in sucha procedure, except: |
Elution of the hybridized DNA from the gel for analysis. |
|
The "c" in cDNA stands for this word: |
Complementary |
|
An expression library contains genes corresponding to all ofthe following, except: |
An expression library could be any of these choices. |
|
A DNA library consists of |
cDNA library |
|
Expression libraries are most often made from |
. the mRNA found with a given cell or tissue. |
|
In the polymerase chain reaction |
it is possible to amplify small amounts of DNA withoutcloning. |
|
The polymerase chain reaction requires |
a. primers complementary to the ends of the sequence to beamplifiedb. carefultemperature control |
|
The following item was the most important one for thedevelopment of PCR as a commercially successful and widely-used procedure: |
Taq DNA Polymerase. |
|
Advantages of the Polymerase Chain Reaction include all ofthese, except: |
a. The reaction is specific for certain sequences in the DNA.b. Onlysmall amounts of template are needed.c. Resultscan be obtained with DNA that is old or partially degraded.d. All theproducts from a specific part of the DNA will be the same size.*e. All ofthese are advantages of PCRÒ. |
|
The best primers for the PCR reaction have the followingfeature: |
. They should anneal rapidly, before the larger DNA strandsreanneal. |
|
Which of the following is a unique feature of qPCR comparedto the original PCR? |
In qPCR, the speed with which the DNA is produced is used toestimate how much of the original template was in the reaction vessel |
|
The RFLP technique |
is used on the DNA of organisms that have two sets ofchromosomes |
|
The usefulness of blotting techniques in molecular biology isthat |
transferred material is in the same relative position on thedisk as on the original sample
|
|
The following blotting procedure is named for the scientistwho invented it: |
Southern |
|
Which of the following is true? |
DNA evidence is easier to use to exclude a putative matchthan to include it |
|
Slight differences in a given gene between the two homologouschromosomes are called |
alleles |
|
Forensic uses of DNA to identify victims or criminals exploitthe following trait in DNA: |
Differences in sizes of DNA fragments (RFLPs). |
|
When fluorescent markers are used for DNA sequencing: |
computer analysis can help in the detection of sequencinganalysis at a faster rate |
|
A feature of the Sanger-Coulson method for DNA sequencing is |
direct "reading" of the sequence of bases |
|
In DNA sequencing, fragments to be analyzed are produced by |
selective interruption of DNA synthesis |
|
RNA is sequenced by |
sequencing the complementary DNA produced by the reversetranscriptase reaction |
|
A proteome is |
a collection of all the proteins produced in a given cell ortissue. |
|
Microarrays allow the analysis of thousands of samples of DNAor protein to be performed simultaneously. |
True |
|
A transcriptome is |
a collection of all the genes being transcribed in a givencell or tissue at a given time. |
|
In a metabolic study using microarrays, a yellow dotrepresents the location of DNA on the microarray: |
for which mRNA was produced in both the control and the testcase |
|
Chpt 14 |
Chpt 14 |
|
Which of the following classes of organisms can virusesinfect? |
a. bacteriab. plantsc. animals*d. All ofthese |
|
The capsid of a virus is composed of |
protein |
|
Colds are commonly caused by |
rhinoviruses |
|
What is the function of protein spikes on a virus? |
They help the virus attach to the host |
|
The large-T protein of SV40 is an example of a(n) |
oncogene |
|
A virus life cycle that involves the incorporation of theviral DNA into the host chromosome is |
lysogeny |
|
A viral genome is |
may be double or single stranded. |
|
With the influenza virus, there are 16 types of ______ |
hemaglutinin (HA) subtypes |
|
What happens to the DNA copy of the retroviral RNA genomeafter it is produced? |
It is incorporated into the host's DNA. |
|
Which of the following best describes the function of reversetranscriptase? |
It uses an RNA template to make a double-stranded DNA |
|
Which of the following is not a feature common to all retroviruses? |
Sarcoma Oncogenes |
|
Clonal selection is the ability of the immune system to control the proliferation of antigen-specific cells, since it has a mechanism to recognize which cells interact with that antigen. |
True |
|
The term antibody is essentially interchangeable with |
immunoglobulin |
|
Antibodies have two binding sites to react with antigens. |
True |
|
Which of the following doesnot arise from a defect in the immune system? |
Sugar intolerance |
|
The first vaccine was made against |
smallpox |
|
Which of the following cell types engulf invaders and display portions of their proteins to other cells? |
dendritic cells |
|
Dendritic cells |
display antigens associated with MHC proteins |
|
Which of the following cell types kills cells that have been infected by viruses or that are cancerous? |
NK cells |
|
The designation of white blood cells as T cells and B cells refers to whether the cells develop primarily in the Thymus gland or the Bone marrow. |
True |
|
Which of the following descriptions of T cells is true? |
They produce interleukins |
|
Which of the following cells actually makes antibodies? |
B cells |
|
An epitope is |
a binding site for an antigen on an antibody |
|
Antibodies are the most variable protein sequences in the human body. |
True |
|
More than one type of antigen can bind to an antibody, butthere is only one type of antibody for each antigen. |
False |
|
Monoclonal antibodies arise from proliferation of a single Bcell. |
True |
|
Hybridomas, which produce monoclonal antibodies, are made by fusing cells of the immune system with |
cancerous cells |
|
Which of the following contributes to the variability of the immunoglobulins? |
a. A variety of different DNA sequences are physicallyattached together to generate a huge number of different antibody genes.b. Thelinking regions between these DNA sequences are also highly variable.c. Thesynthesis of mRNA in the antibody cells is very variable, producing manydifferent proteins from one gene.d. Thereare several hundred to one thousand different genes for the variable part ofthe antibody sequence.*e. All ofthese mechanisms contribute to the variety of antibodies in the immune system. |
|
Which of the following is an example of an autoimmunedisease? |
a.rheumatoid arthritisb. lupusc. someforms of diabetes*d. all ofthese |
|
Viruses can be genetically engineered to specifically targetcancer cells. |
True |
|
The ability of cancer cells to travel to other parts of thebody and produce new tumors is called |
metastasis |
|
Which of the following genes in normal cells can be relatedto oncogenes? |
Oncogenes include examples of all of these. |
|
Proteins which inhibit transcription of genes that would cause increased replication are called |
tumor suppressors |
|
The protein called p53 is especially important in cancerbecause: |
Protein p53 can prevent cells from dividing and cause toenter programmed cell death. |
|
Herceptin is a |
drug designed to fight a specific type of breast cancer |
|
Chpt 15 |
Chpt 15 |
|
Which of the following statements concerning the free energychange (DG) is false? |
The rate of a reaction can be determined from the energychange. |
|
The standard state of a solution is taken as |
1 molar concentration |
|
Consider this rxn which has a DG° = +0.4 kJ/mol.A + B « C + D1 M A, 1 M B, 0.1 M C and 0.1 M D are added to a container at room temperature.Which of the following statements is true? |
The reaction will proceed in the forward direction to reach equilibrium. |
|
Consider this rxn which has a DG° = +0.4 kJ/mol.succinate + FAD « fumarate + FADH21 mM of each compound are mixed & the reaction is allowed to come toequilibrium. Which statement is correct about the resulting concentration ofFAD at equilibrium? |
[FAD] > [FADH2] |
|
Consider this rxn which has a DG° = +0.4 kJ/mol.A + B « C + D1 M A, 1 M B, 0.1 M C and 0.1 M D are added to a container at room temperature.Which of the following statements is true? |
DG < 0 (i.e., it's negative) |
|
Which of the following isnot true concerning standard states? |
For pure liquids, the standard state is 1M |
|
I am performing a reaction, A ® B, with DG°' = -0.3 kJ/mol. Istart the reaction with 10 mM A and no B. After allowing the reaction toproceed for 24 hrs at room temperature and atmospheric pressure, I analyze asample of the reaction mix to find I now have 1 mM A and 9 mM B. Which of thefollowing conclusions should I make? |
I must've screwed up; there's no way I could get that resultwith that DG°' |
|
I am performing a reaction, A ® B, with DG°' = -5000 kJ/mol.I start the reaction with 10 mM A and no B. After allowing the reaction toproceed for 24 hrs at room temperature and atmospheric pressure, I analyze asample of the reaction mix to find I now have 8 mM A and 2 mM B. Which of thefollowing conclusions should I make? |
I should come back again later; equilibrium has not yet beenreached. |
|
Biochemists use a modified value for standard DG valuesbecause |
the pH in living systems is seldom, if ever, near 0. |
|
Which best describes the DG for hydrolysis of creatine phosphate under cellularconditions in which the concentration of creatine phosphate, creatine, andphosphate all equal 1 mM at 25°C. The DG° for the hydrolysis of creatinephosphate at 25°C is -43 kJ/mol. |
DG < -43 kJ/mol |
|
By definition, a spontaneous reaction is one in which |
energy is released. |
|
The standard state usually used in biochemistry (DG°')includes |
all concentrations at 1 M, except for [H+], which is10-7 M. |
|
"Metabolism" refers to |
a. the breakdown of larger molecules into smaller ones.b. theproduction of larger molecules from smaller ones. |
|
The production of larger molecules from smaller ones iscalled |
anabolism |
|
In general, catabolism |
releases energy |
|
In general, catabolism |
is an oxidative process that releases energy |
|
Which of the following statements apply to anabolism? |
a. proceeds in stagesb.requires energyc.requires reducing agents*d. all ofthese |
|
"Oxidation" refers to |
the loss of electrons |
|
An oxidizing agent |
gains electrons |
|
During reduction |
electrons are lost. |
|
In general, the anabolic pathways tend to involve oxidationreactions. |
False |
|
Which of the following is not true? |
Molecular oxygen is always a substrate in oxidationreactions. |
|
Which of the following coenzymes is not a carrier of electrons in biological redox reactions? |
Coenzyme A |
|
In biological redox reactions, hydrogen ions are usuallytransferred along with electrons. |
True |
|
Which of the following coenzymes is derived from riboflavin? |
FAD |
|
Which of the following is not a part of FAD? |
nicotinamide |
|
The conversion of NAD+ to NADH is an example of reduction because |
the pyridine ring gains electrons (and a hydrogen) |
|
In the coenzyme FAD the site to which electrons aretransferred is |
a nitrogen-containing ring system |
|
What happens to the entropy when ATP is hydrolysed to ADP? |
Entropy increases |
|
The oxidation of nutrients supplies the energy to produceATP. |
True |
|
In order to drive the synthesis of ATP, the hydrolysis of anorganic phosphate |
must have a higher free energy change. |
|
Considerthese reactions: ATP ® ADP + Pi DG°' = -31 kJ/mol glucose-6-phosphate ® glucose + Pi DG°' = -13 kJ/mol glucose + ATP ® glucose-6-phosphate + ADP DG°' = ? What is the DG°' of the last reaction? |
-18 kJ/m |
|
ATP is a good source of energy to run metabolic reactions forall the following reasons, except: |
The sugar group is very reactive. |
|
The body allows energy consuming reactions to occur bycoupling them with reactions which have a negative DG. |
True |
|
The number of degrees of freedom a molecule has is related tothe numbers of resonant structures it has. |
True |
|
What happens to the entropy of a molecule as the number ofresonance structures increases? |
Entropy also increases |
|
Many cells oxidize fatty acids to produce ATP. If no ATP wereproduced, the DG°' of this process would be |
a larger negative number |
|
When we say that the efficiency of glycolysis is about 33% wemean that |
the energy used to phosphorylate 2 ATP is 33% of the energyreleased in the process |
|
The energy released during metabolism of nutrients can beused to synthesize ATP from ADP and phosphate. |
True |
|
In order to initiate many metabolic pathways it is necessaryto activate the starting materials. |
True |
|
If the reaction A ® B has DG = +25 Joule/mol and the reactionB ® C has DG = -15 Joule/mol, the overall energy change A ® C will be |
+10 Joule/mol |
|
Which of the following are examples of endergonic processes? |
protein synthesis and active transport |
|
Which of the following are examples of exergonic processes? |
oxidation of fats and of carbohydrates |
|
The phosphorylation of ADP to produce ATP is endergonic because |
a negatively charged ion is bonded to a molecule that alreadycarries a negative charge |
|
Spontaneous reaction always occurs at a relatively fast rate. |
False |
|
The efficiency of aerobic metabolism is greater than that ofanaerobic metabolism even though much more energy is released in aerobic thanin anaerobic metabolism because |
aerobic metabolism traps much more energy in the form of ATPthan does anaerobic metabolism |
|
The hydrolysis of ATP can be used to drive reactions thathave a DG°' that is |
less than +5 kJ/mol |
|
The linking of an exergonic reaction to drive an endergonicreaction is called: |
coupling |
|
What happens to the entropy when ATP is hydrolysed to ADP? |
Entropy increases |
|
In metabolism the term "activation" refers to |
conversion of a component of a metabolic pathway into are active compound. |
|
An example of an activation step in metabolism is |
the formation of an acyl derivative of coenzyme A. |
|
Which of the followingis not a mechanism used to activate substrates for furthermetabolism? |
Hydrolyzing a polymer into its component monomers. |
|
Metabolism takes place in stages |
and allows for efficient production and use of energy |
|
Chpt 16 |
Chpt 16 |
|
Which of the following monosaccharides is a ketose? |
fructose |
|
Haworth projection formulas |
a. arerepresentations of the cyclic form of sugarsb. canshow the distinction between the a and b anomers |
|
Which of the following isnot a function of carbohydrates? |
They are catalytic components of enzymes. |
|
How many carbon atoms are in the simplest carbohydrates? |
3 |
|
The simplest ketotriose is |
dihydroxyacetone |
|
Mirror image stereoisomers are called |
enantiomers |
|
The simplest aldotriose is: |
glyceraldehyde |
|
In a Fischer projection, which chiral carbon determines whether the sugar is the D- or the L-isomer? |
highest numbered asymmetric carbon atom |
|
For the a anomer of a D-sugar, the anomeric hydroxyl in aHaworth projection |
has a downward projection (on the opposite side from theterminal CH2OHgroup). |
|
Diastereomers are |
non-mirror-image, nonsuperimposable stereoisomers. |
|
Epimers are |
stereoisomers that differ from each other in their configuration at a single carbon atom. |
|
D-erythrose is to D-ribose as D-ribose is to: |
D-allose |
|
How many enantiomeric pairs are possible for a aldohexose? |
8 |
|
Sugars which differ in chirality only around one carbon aremost specifically called |
epimers |
|
Aldoses can form which type of cyclic structure? |
Hemiacetal |
|
The cyclic form of sugars |
has one more chiral center (the anomeric carbon) than theopen-chain form. |
|
Epimers of D-Glucose include: |
L-Idose and D-Galactose |
|
Diastereoisomers of D-Glucose include all of these, except: |
D-Fructose |
|
Isomers of sugars in which the position of ketone andaldehyde groups have been changed are called |
a. anomers.b.diastereoisomers.c.enantiomers.d.epimers.*e. noneof these |
|
Which carbon of the open-chain form of a sugar becomes theanomeric carbon in the cyclic form? |
the carbonyl carbon |
|
The a and b forms of the same sugar are called |
anomers |
|
A pyranose is a sugar that |
contains a six-membered ring as part of its cyclic structure. |
|
A furanose is a sugar that |
contains a five-membered ring as part of its cyclicstructure. |
|
For a D-sugar, any group that is written to the right of thecarbon in a Fischer projection |
has a downward projection in a Haworth projection. |
|
Which of the following groups is produced when an aldehyde isoxidized? |
carboxyl |
|
A lactone is a cyclic |
ester |
|
Which of the following compounds is produced by oxidation ofan aldose in the cyclic form? |
a lactone |
|
Two samples containing identical mixtures of sugars areanalyzed, one using Tollen's reagent, the other with glucose oxidase. Whichwill give a stronger reaction? |
Tollen's reagent |
|
The conversion of a sugar's carbonyl to an alcohol is |
a reduction reaction |
|
Deoxyribose is best described as a(n): |
glycoside |
|
When monosaccharides are bonded together |
a. one H2O molecule is lost for each new link formed.b.oligosaccharides are formed by combining a few monosaccharides.c.polysaccharides are formed by combining many monosaccharides.*d. all ofthese |
|
Which of the following best describes the glycosidic bond inthe disaccharide shown? |
a(2-4) |
|
Glycosidic bonds from sugars |
may link to the other molecule through either an oxygen or anitrogen atom |
|
Which of the following statements concerning sugar polymersis false? |
Linear polymers are more water-soluble than branched ones |
|
Glycosidic linkages between monosaccharide units may varybased on |
a. theanomeric form of the cyclic structure, i.e.,a or b.b. which-OH group is involved. |
|
Which of the following is true concerning the moleculepictured? |
It is not a reducing sugar because the anomeric hydroxyl ismethlyated |
|
Common table sugar is |
sucrose |
|
Sucrose is composed of the following simple sugars: |
glucose and fructose |
|
Maltose is composed of the following simple sugars: |
glucose only |
|
The difference between cellobiose and maltose is: |
one has an á linkage and the other a â linkage |
|
Which of the following isnot a reducing sugar? |
sucrose |
|
Which of the following artificial sweeteners is a chemicalderivative of sucrose? |
sucralose |
|
Lactose is composed of the following simple sugars: |
glucose only |
|
The following sugar is also called milk sugar: |
Lactose |
|
The following sugar is also called fruit sugar: |
Fructose |
|
The following sugar is also called blood sugar: |
Glucose |
|
Which of the following molecules is a disaccharide? |
lactose |
|
Lactose intolerance |
arises from inability to metabolize the disaccharide lactose |
|
Which of the following disaccharides cannot be digested by mammals? |
cellobiose |
|
Which of the following statements associated with celluloseis false? |
Most animals can easily digest this compound. |
|
Cellulose is indigestible to most animals because |
animals do not have the enzymes needed to hydrolyze theb-glycosidic linkages between the monomer units |
|
Humans are not able to digest cellulose as a food sourcebecause: |
Cellulose is insoluble and we lack the enzyme to break the blinkage in the cellulose. |
|
In bacterial cell walls |
peptides form crosslinks between polysaccharides |
|
Which of the following molecules have the highest degree ofa[1-6] branching linkages |
Glycogen |
|
A polysaccharide. Whichlettered subunit is the nonreducing end? |
There is more than one nonreducing end on this carbohydrate. |
|
A major difference between amylose and amylopectin is that |
amylopectin is branched and amylose is not |
|
The linkage between the glucose residues in amylopectin andglycogen is: |
For the main chain a (1 ® 4) and a (1 ® 6) for the branches |
|
Glycogen is |
a highly branched polysaccharide found in animals |
|
Which of the following has only a[1-4] linkages and no a[1-6]linkages |
Amylose |
|
Glycogen has a similar structure to amylopectin, but is lesshighly branched. |
False |
|
Glycogen breakdown proceeds from the nonreducing ends. |
True |
|
Glycogen is sometimes called animal starch |
True |
|
Plant starch includes amylopectin and cellulose |
False |
|
A bacterial cell wall is composed of: |
A polysaccharide consisting of 2 types of monosaccharideunits and cross-linking oligopeptides. |
|
There are two forms of starch: |
amylose, which is a linear polysaccharide, and amylopectin,which is highly branched |
|
The blue color in a well-known test for the presence ofstarches is due to |
the formation of a complex between iodine and amylose |
|
Amino or acid derivatives of sugars are very important inwhich of the following biological functions? |
a. Structural rolesb.Lubricating fluidsc. Cellsurface sugars used in cell identityd. Bothstructural roles and lubricating fluids.*e. All ofthe above are functions of amino and acid sugar derivatives. |
|
Cell walls |
are found in plants and bacteria, but have different chemicalcompositions |
|
One major difference between bacterial and plant cell wallsis that bacterial cell walls have polysaccharides that are crosslinked bypeptides. |
True |
|
Insoluble fiber in the diet is better at binding toxicsubstances than soluble fiber. |
False |
|
The most common biopolymer on earth is this carbohydrate: |
Cellulose |
|
Insoluble fiber in the diet is better at better at providingbulk and stimulating peristaltic action than soluble fiber. |
True |
|
Polysaccharides used in cell wall structure contributerigidity to the wall due to covalent cross-linking between the fibers. |
False |
|
Chitin, which forms the exoskeletons of insects, is composedof |
b(1-4) linked N-acetylglucosamine residues |
|
One advantage of branched sugar polymers is the availabilityof more ends for chemical reaction. |
True |
|
Which of the following statements concerning plant cell wallsis false? |
They contain large amounts of protein. |
|
Blood typing depends on |
the nature of the oligosaccharide portion of glycoproteins onthe surface of red blood cells |
|
Cartilage and mucous are both slippery because: |
Both charge repulsion of acidic groups and the sticky natureof sugars. |
|
Glycoproteins |
are proteins to which sugars are covalently bonded |
|
The main difference, on the surface of a red blood cell,between the A-B-O major blood groups depends on |
the presence or absence of a certain sugar. |
|
Which of the following is true about the ABO blood groups? |
all three of the blood groups have an á-L-fucose groupattached |
|
Chpt 17 |
Chpt 17 |
|
Glycolysis |
does not require O2 togenerate energy. |
|
The fate of pyruvate produced during glycolysis dependsprimarily on the availability of |
molecular oxygen. |
|
In aerobic metabolism, what is the fate of pyruvate producedby glycolysis? |
Pyruvate loses carbon dioxide, and the remaining two carbonatoms become linked to coenzyme A. |
|
In humans, pyruvate can be converted to |
acetyl-CoA and lactate. |
|
Which of the following is not an end product of glucosemetabolism via either aerobic or anaerobic means? |
fructose |
|
What is the net ATP yield per glucose during glycolysis? |
2 |
|
In the conversion of glucose to pyruvate, how many of theactual steps involve electron transfer? |
1 |
|
The order of compounds in the conversion of glucose topyruvic acid is as follows: (PEP = phosphoenolpyruvate) |
Fructose-6-phosphate, fructose-bisphosphate, 1,3-phosphoglyceric acid, 3-phosphoglyceric acid,PEP. |
|
Which of the following is not true? |
Corn is the only source of biofuels |
|
Which of the following terms describes an enzyme thattransfers a phosphate group from ATP to a substrate? |
kinase |
|
The DG values for glycolytic reactions at physiologicalconditions may be exergonic, even though the DG°' at "standard"conditions, may be endergonic. |
True |
|
The reactions where glucose is converted to glucose6-phosphate and fructose 6-phosphate is converted to fructose 1,5-bisphosphateare examples of: |
a. exergonic reactionsb. primingreactionsc. phosphorylationreactionsd. kinasereactions*e. all ofthese |
|
The phosphorylation of glucose to glucose 6-phosphate |
is an endergonic reaction that takes place because it iscoupled to the exergonic hydrolysis of ATP. |
|
The enzyme glucokinase |
specifically phosphorylates glucose rather than other sugars. |
|
Which enzyme catalyzes the reaction shown? |
an isomerase |
|
The binding of glucose to hexokinase |
is an example of induced-fit binding of a substrate to theactive site of an enzyme. |
|
The phosphorylation of fructose 6-phosphate to fructose-1,6-bisphosphate is the committed step inglycolysis because |
fructose 1,6-bisphosphatecan undergo no other reactions than those of glycolysis. |
|
Which of the following sugars can be a substrate forhexokinase? |
a. glucoseb.fructosec. mannose*d. all ofthese |
|
Which of the following enzymes interconverts an aldose and aketose? |
isomerase |
|
Which enzyme is the key regulatory enzyme in glycolysis? |
Phosphofructokinase |
|
Which of the following exercise(s) allosteric control in thereaction of phosphofructokinase? |
a. ATPb.fructose 2,6-bisphosphate |
|
The reaction of fructose 1,6-bisphosphate to give glyceraldehyde-3-phosphate anddihydroxyacetone phosphate is an example of |
a reverse aldol condensation. |
|
The equilibrium for isomerization of dihydroxyacetonephosphate to glyceraldehyde-3-phosphate is favored because |
glyceraldehyde-3-phosphate is being continuously drained offfor the subsequent reaction in the glycolytic pathway |
|
The isomerization of dihydroxyacetone phosphate to giveglyceraldehyde 3-phosphate |
is catalyzed by the enzyme triose phosphate isomerase. |
|
The step that commits the cell to metabolize glucose iscatalyzed by |
phosphofructokinase |
|
Theequilibrium for the formation of glyceraldehyde-3-phosphate fromdihydroxyacetone phosphate is driven by |
having the product of the reaction continuously consumed. |
|
Which of the following enzymes catalyzes the cleavage offructose bisphosphate into two3-carbon units? |
Aldolase |
|
Which of the following is not true? |
. Every reaction in a metabolic pathway must have a negativeDG, or the pathway cannot run. |
|
Which of the following terms describes an enzyme thatcatalyzes electron transfer reactions? |
dehydrogenase |
|
Which of the following enzymes forms a thioester using acysteine residue as a key intermediate? |
glyceraldehyde-3-phosphate dehydrogenase |
|
In glycolysis, ATP is synthesized by |
substrate-level phosphorylation |
|
Enolase catalyzes |
the dehydration of 2-phosphoglycerate. |
|
The nicotinamide-binding region in glyceraldehyde-3-phosphatedehydrogenase is similar to all other NAD binding domains. |
True |
|
During glycolysis, ATP is synthesized from ADP and aphosphate group transferred from an acid anhydride. |
True |
|
What is the name of the pictured glycolytic intermediate? |
3-phosphoglycerate |
|
Which of the following is required for substrate-level phosphorylation? |
The standard free energy of the hydrolysis reaction is morenegative than that for hydrolysis of the new phosphate compound being formed. |
|
The amino acid cysteine is important in adding a secondphosphate to glyceraldehyde phosphate in the glyceraldehyde-3-phosphatedehydrogenase reaction. |
True |
|
Which of the following enzymes of glycolysis is not involved in regulation of thepathway? |
Aldolase |
|
Which of the following glycolytic enzymes forms a mixedanhydride from phosphoric acid? |
glyceraldehyde-3-phosphate dehydrogenase |
|
How many enzymes of glycolysis are control points for thepathway? |
3 |
|
Which of the following enzymes catalyzes a dehydrationreaction? |
Enolase |
|
In the conversion of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate |
an aldehyde is oxidized to a carboxylic acid. |
|
An enzyme notinvolved in the control of glycolysis is |
triose phosphate isomerase. |
|
How many different reactions involve substrate-levelphosphorylation during glycolysis? |
2 |
|
The reduction of pyruvate to lactate |
allows for recycling of NAD+. |
|
Anaerobic metabolism can occur in all these organisms orcells, except: |
Anaerobic metabolism can occur in all of these. |
|
Which of the following enzymes of anaerobic metabolism is not tetrameric? |
Hexokinase |
|
Which of the following is not true? |
The M4 version of lactatedehydrogenase predominates in heart tissue |
|
During anaerobic metabolism in yeast, the carbons of glucoseend up in |
both CO2 and ethanol. |
|
Which of the following enzymes relies on thiaminepyrophosphate as a cofactor? |
pyruvate decarboxylase |
|
Fetal alcohol syndrome |
can be detected by measuring the level of acetaldehyde in thebloodstream of a pregnant woman |
|
During anaerobic metabolism in red blood cells, the carbonsof glucose end up in |
lactic acid. |
|
Alcohol dehydrogenase resembles lactate dehydrogenase in thatit |
uses NAD+ as a coenzyme. |
|
Thiamine pyrophosphate is a coenzyme |
involved in transfers of two-carbon groups. |
|
The fate of NADH from glycolysis depends on whetherconditions are anaerobic or aerobic. |
True |
|
Methanol is extremely toxic, but not directly. In the body,it is converted into formaldehyde; that's what's actually the poison. What kindof enzyme catalyses this conversion? |
dehydrogenase |
|
The percentage of energy captured as ATP during theconversion of glucose to lactate is closest to |
30% |
|
If glycolysis did not lead to the production of ATP, theoverall process would |
release more energy |
|
When humans consume ethanol, the first step in its metabolismis: |
conversion to acetaldehyde |
|
Chpt 18 |
Chpt 18 |
|
Which of the following statements concerning branchedpolymers like glycogen is false? |
All of the reducing ends of the branched polymer areavailable to release glucose. |
|
What is the average chain length of the branches in glycogen? |
13 glucose residues |
|
Glycogen is mainly found in |
liver and muscle. |
|
Which of the following best describes how liver suppliesother tissues with the glucose it releases from its stored glycogen? |
It releases glucose into the blood. |
|
The enzyme that catalyzes the interconversion ofglucose-1-phosphate and glucose-6-phosphate is |
a mutase. |
|
Glycolysis that starts with glycogen instead of glucose canbe considered to have a higher energy yield because: |
Phosphorylase produces a glucose phosphate without spendingan ATP to do it |
|
Which enzyme cleaves the a(1 ® 6) bonds in glycogen? |
debranching enzyme |
|
What kind of reaction is used to release glucose units fromglycogen? |
phosphorolysis |
|
The enzyme glycogen phosphorylase catalyzes a reaction in |
glycogen breakdown. |
|
If an individual lacked the debranching enzyme, the effectwould be: |
the individual would not be able to completely break down aglycogen molecule |
|
Which of the following best describes the function ofdebranching enzyme? |
It transfers a set of three glucose residues from a limitbranch and then cleaves the a(1 ® 6) bond via hydrolysis. |
|
The compound uridine diphosphate glucose (UDPG) plays a rolein |
glycogen synthesis |
|
The activity of glycogen phosphorylase depends on |
a. allosteric controlb.covalent modification |
|
Glucose-6-phosphatase activity is found associated with theendoplasmic reticulum. |
True |
|
How are the branches in glycogen produced? |
A branching enzyme moves a short chain of several glucoseunits from a linear a(1,4) section of glycogen to make a new a(1,6) branchpoint. |
|
UDP-glucose pyrophosphorylase works by this mechanism: |
It adds a UMP molecule to glucose-1-phosphate by splittingout pyrophosphate. |
|
Which of the following reactions occur when a single glucoseresidue is transferred from UDP-glucose to a growing glycogen molecule? |
a. UDP is released.b. Theglucose can be attached to a #4 carbon atom in the glycogen molecule.c. UDP isreleased and the glucose is attached to a #4 carbon.*d. All ofthese events can occur when a single glucose residue is added. |
|
Glycogen phosphorylase |
a. exists in two forms, phosphorylase a and phosphorylase bb.responds differently to allosteric effectors in its phosphorylated anddephosphorylated forms |
|
Starting from glucose and UTP and ATP, how many high-energybonds are broken/consumed to add that glucose to a glycogen molecule? |
2 |
|
When glycogen synthase is phosphorylated |
its activity decreases. |
|
When glycogen phosphorylase is phosphorylated |
its activity increases. |
|
Where is the enzyme glucose-6-phosphatase located? |
endoplasmic reticulum |
|
Glycogen phosphorylase and glycogen synthase |
are not activated simultaneously |
|
Glycogen synthase and glycogen phosphorylase |
are modified by the same enzymes |
|
Hydrolysis of pyrophosphate is an important energy drivingforce in the synthesis of glycogen. |
True |
|
Which of the following isnot a control mechanism for glycogen phosphorylase? |
Subunit association and dissociation. |
|
Of the various forms of glycogen phosphorylase, the mostactive would be: |
the phosphorylated R form |
|
Branching and debranching enzymes use the exact samemechanism to add and remove the branches of the glycogen polymer. |
False |
|
The same enzymes are responsible for covalentmodifications of both glycogen synthase and glycogen phosphorylase inregulating their activity. |
True |
|
Generally speaking, the same mechanisms that activateglycogen phosphorylase will turn off glycogen synthase. |
True |
|
Which of the following isnot an advantage that glycogen provides to muscle cells in which it isstored? |
It draws more water into the cells than glucose would. |
|
Glycogen loading is particularly advantageous for providingenergy for long distance athletic events, such as running the marathon. |
False |
|
Properly used, glycogen loading by athletes is a safeprocess. |
True |
|
Which of the following molecules does not directly regulate the activity of glycogen synthase? |
Glucose |
|
There is as much energy used to add a phosphate group bymeans of phosphorolysis, as the energy required adding a phosphate using ATP. |
False |
|
Gluconeogenesis is the synthesis of |
glucose from non-carbohydrate precursors |
|
Gluconeogenesis differs from glycolysis because |
a. the irreversible steps of glycolysis are bypassedb.different enzymes are involvedc. biotinis required for gluconeogenesis and not for glycolysis*d. all ofthese |
|
Which enzyme is used in gluconeogenesis, but NOT in glycolysis? |
PEP carboxykinase |
|
The enzyme pyruvate carboxylase |
requires biotin for activity |
|
In which cellular compartment is pyruvate carboxylase found? |
mitochondria |
|
Which of the following statements concerning biotin andgluconeogenesis is false? |
CO2 is incorporated into theglucose product. |
|
The regulatory enzymes in gluconeogenesis are |
glucose-6-phosphatase, fructose-1,6-bisphosphatase, pyruvate carboxylase, and phosphoenolpyruvatecarboxykinase |
|
In gluconeogenesis, the initial reaction converts pyruvate to |
oxaloacetate |
|
The first reaction of gluconeogenesis is |
a carboxylation |
|
Which nucleotide triphosphate is hydrolysed in the conversionof oxaloacetate to phosphoenolpyruvate? |
GTP |
|
The NADH used for the reduction reactions duringgluconeogenesis usually come from this reaction: |
Malate dehydrogenase activity in the cytoplasm. |
|
Which of the following is true? |
In gluconeogenesis, the effective reversal of the glycolyticreactions of hexokinase and phosphofructokinase involve the same sugarmolecules but not the exact set of substrates and products |
|
How many ATP equivalents are expended to convert 2 pyruvatesto 1 glucose? |
6 |
|
It is impossible to reverse any kinase reaction underphysiological conditions. |
True |
|
In general, opposing pathways, such as glycolysis andgluconeogenesis are not exactreversals of each other. |
True |
|
The formation and breakdown of fructose 2,6-bisphosphate |
is catalyzed by the same protein dependant upon whether it isphosphorylated or not. |
|
High concentrations of fructose-2,6-bisphopshate |
stimulate glycolysis and inhibit gluconeogenesis. |
|
The activity of the enzyme fructose 1,6-bisphosphatase is |
inhibited by fructose 2,6-bisphosphate. |
|
In the process of substrate cycling |
different enzymes, subject to independent control, areresponsible for the synthesis and breakdown of the same substance. |
|
The molecule fructose 2,6-bisphosphate: |
is an important regulatory molecule in the control ofcarbohydrate metabolism |
|
Which of the following is not true concerning control ofpyruvate kinase? |
a. The phosphorylated form is less activeb. It isinhibited by ATPc. It isactivated by fructose 1,6-bisphosphated. It isinhibited by low blood glucose levels*e. All ofthese |
|
The enzyme glucose-6-phosphatase is only found in cells whichhave this function or ability: |
Ability to replenish the levels of glucose in the blood. |
|
If you're running away from a bear, |
your liver cells will be running gluconeogenesis and your legmuscle cells will be running glycolysis. |
|
In the Cori cycle |
glycolysis takes place in muscle and gluconeogenesis in theliver. |
|
The process called substrate cycling is used to describe thisprocess: |
Situations where there are two different enzymes used toreverse a specific step in a metabolic pathway. |
|
The Cori cycle involves the following: |
Conversion of lactate produced in the muscle by regenerationof glucose in the liver. |
|
Which of the following mechanisms can be used to regulatemetabolic pathways? |
a. Allosteric activators and inhibitors.b.Covalent modifications of enzymes.c. Use ofseparate enzymes at a given point in the forward and backward pathways.d.Regulation of the genes for the enzymes used in the pathway.*e. All ofthese are used to regulate metabolism. |
|
The liver contains a special enzyme, hexokinase, to act as abackup for glucokinase when the glucose levels in the body get very high. |
False |
|
The primary function of the pentose phosphate pathway is |
to synthesize NADPH and pentose phosphates. |
|
During the pentose phosphate pathway (glucose-6-P ®ribose-5-P), is there a net oxidation of the substrate carbon atoms? |
It depends on whether the glucose goes through the oxidativepart of the pathway or not. |
|
What kind of enzyme catalyzes the following reaction?ribose-5-P « ribulose-5-P |
isomerase |
|
What kind of enzyme catalyzes the reaction ribulose-5-P «xylulose-5-P? |
epimerase |
|
Which of the following statements concerning the initialphase of the pentose phosphate pathway is false? |
The process reduces glucose-6-phosphate. |
|
In one normal cycle of the pentose phosphate pathway, theenzyme transaldolase is used twice and the enzyme transketolase is used once. |
False |
|
The oxidative reactions of the pentose phosphate pathway |
produce NADPH rather than NADH. |
|
The conversion of ribulose 5-phosphate to xylulose5-phosphate is |
an epimerization |
|
A characteristic of the reaction catalyzed by transaldolaseis |
transfer of a three-carbon unit |
|
Which of the following molecules is not a product of the pentose phosphate pathway? |
glycerate-3-phosphate |
|
Control of the entry of glucose or fructose into theoxidative portions of the pentose phosphate pathway is mostly dependent on acell's need for NADPH, rather than on the cell's need for pentoses. |
True |
|
The enzyme phosphopentose isomerase is characterized by allthe following except |
it catalyzes an inversion of configuration at carbon-3 |
|
In addition to pentoses, the pentose phosphate pathwayinvolves sugars of all these sizes except: |
a. 3 carbonsb. 4carbonsc. 6carbonsd. 7carbons*e. All ofthese sizes are used in this pathway. |
|
The vitamin thiamine is important in transferring all ofthese types of groups, except: |
Thiamine can transfer all of these types of groups. |
|
All of the following sugar rearrangements are part of thepentose phosphate pathway, except. |
C5 + C5 ® C6 + C4 |
|
Hemolytic anemia is associated with the pentose phosphatepathway because: |
a. a deficiency of this pathway leads to a lack of NADPH inred blood cellsb. NADPHis required to reduce glutathionec. Redblood cells have minimal resources for maintaining an oxidative balance*d. all ofthese |