Question

QUESTION 34

1. A mutation in themitochondria is limited in its cellular effects primarilybecause

   a.		there are so few genescarried by the mitochondria
   b.		there is so muchuntranslated or "junk" DNA in the mitochondria
   c.		the genes in themitochondria are not critical for cellular function
   d.		there are so manycopies of mtDNA in each mitochondria
   e.		mtDNA is only passeddown from the mother

1points

QUESTION 35

1. All of the followingare required for HIGH-level expression of the lacstructural genes EXCEPT:

   a.		RNA polymerase + sigmafactor
   b.		CAP-cAMP
   c.		LacI bound toallolactose
   d.		glucose

1points

QUESTION 36

1. A woman withfacioscapulohumeral muscular dystrophy (FMD), an autosomal dominanttrait, is seeking advice on having children. FMD does not run inher family. Her husband, who is 28 and normal, has an uncle withHuntington's disease (HD; autosomal dominant). His parents arenormal, and both are over 50. Symptoms of Huntington's disease mayappear from 12 to 65 years after birth; however, all HD members ofhis father's kindred developed signs during their thirties. HD andFMD are fully penetrant. What are the genetic risks for thiscouple's children?

   	a.	50% FMD, 50% HD
   b.		100% FMD, 0% HD
   c.		50% FMD, 0% HD
   d.		50% FMD, 25% HD
   e.		0% FMD, 50% HD

1points

QUESTION 37

1. E. colistrains that are Hfr strains _______.

   	a.	possess an Ffactor that has integrated into the bacterial chromosome
   b.		have a low frequencyof recombination
   c.		possess an Ffactor in the cytoplasm
   d.		are susceptible toinfection by a bacteriophage

1points

QUESTION 38

1. I have a spermatagoniacell (the cell that makes sperm) and it is undergoing meiosis. Ithas a non-disjunction event, and of the 4 spermatids created, twohave 24 chromosomes, and two have 22 chromosomes. Whathappened?

   a.		A non-disjunctionevent in meiosis I
   b.		A non-disjunctionevent in meiosis II
   c.		A non-disjunctionevent in mitosis
   e.		A mutation in thecentromere
   f.		A mutation in the sexchromsome

1points

QUESTION 39

1. An individual with adisease demonstrates a set phenotypic presentation, let us say theinability to appreciate 80's music, a most terrible affliction.Another individual with the same phenotypic presentation isdiscovered. When we sequence their genome, we find that there aretwo distinct DNA sequences involved, both differing fromwt, but they are located in the same gene in bothindividuals. This demonstrates

   	a.	Allelicheterogeneity
   b.		Locusheterogeneity
   c.		Pleitropy
   d.		Penetrance
   e.		Expressivity

1points

QUESTION 40

1. What is the mostlikely genetic consequence of a homozygous translocation?

   a.		abnormal pairing ofchromosomes duting meiosis
   b.		gene duplications
   c.		inviable gameteformation
   d.		an alteration in thelinkage relationship of genes
   e.		formation of abnormalchromatids following crossing-over

1points

QUESTION 41

1. From your reading,attenuation in trp gene regulation is accomplished by

   a.		repressing thetrp operon's operator.
   b.		reducing the cell'spermeability to the effector molecule, tryptophan.
   c.		blocking transcriptioninitiation at the trp operon's promoter.
   d.		forming secondary mRNAstructures in the leader region of the transcript.

1points

QUESTION 42

1. Which of the followingexplains why the lac operon is regulated by cataboliterepression, a positive control mechanism that is sensitive to theamount of glucose available to the cell?

   a.		Catabolite repressionallows the cell to choose glucose over lactose when both areavailable.
   b.		Catabolite repressionallows the cell to stockpile the enzymes needed for lactosemetabolism.
   c.		Catabolite repressioninhibits synthesis of the lac repressor, lacI, untilglucose is consumed.
   d.		Catabolite repressionallows the cell to store sugars for use later.

1points

QUESTION 43

1. I talked about a fewspecific diseases caused by chromosomal deletions. Which of thefollowing is not casued by a chromosomal deletion?

   	a.	Cri-du-chat
   b.		Prader-Willi
   c.		Fragile X Syndrome

1points

QUESTION 44

1. Which of the followingprovides the BEST explanation for how alacI^S mutation carries out itsfunction in a trans-dominant manner?

   	a.	The mutation affectsthe expression of genes located on another piece of DNA
   b.		The mutation continuesto affect cells for multiple generations.
   c.		The mutation affectsbacterial cells that do not carry the lacISallele.
   d.		The mutation affectsupstream or downstream genes on the same chromosome.

1points

QUESTION 45

1. I mate an individualthat is AaBbCcDd to another individual that is AaBbCcDd (Bothheterozygotes for all 4 genes). What is the probability that achild they have is homozygous dominanat for all of these genes?

   a.		1/16
   b.		1/64
   c.		1/256
   d.		1/8
   e.		3/4
   f.		1/2

1points

QUESTION 46

1. mtl,polA, and xyl are bacterial genes that can betransmitted using an Hfr strain. An interrupted matingexperiment resulted in xyl transconjugants appearing at 7minutes and reaching maximum level by 30 minutes. The mtltransconjugants appeared at 11 minutes and leveled off at 80%maximum by about 33 minutes, while polA did not appearuntil 24 minutes and then only rose slowly to about 30%. Which ofthe following lists the gene order and direction of insertioncorrectly?

   a.		mtl polA xyl?
   b.		xyl mtl polA?
   c.		polA mtl xyl?
   d.		mtl xyl polA?

1points

QUESTION 47

1. Which of these is themost true of mtDNA?

   	a.	It is resistant tomutation.
   b.		It is not wrappedaround histones.
   c.		It is only replicatedduring cellular meiosis.
   d.		It is only replicatedduring S phase.
   e.		It has large numbersof exons.

1points

QUESTION 48

1. Familial Downs,creating an inherited form of a disease also caused by chromosomenondisjunction, can be caused by

   	a.	Robertsoniantranslocations
   b.		deletion of chromosome21
   c.		Philadelphiachromosome
   d.		dating NAUstudents
   e.		inversion ofcentromeric DNA regions

1points

QUESTION 49

1. If two chiasmataoccurr between two genes, the resulting phenotype for thisrecombination would be

   a.		parental.
   b.		singlerecombinant.
   c.		doublerecombinant.
   d.		dominant.
   e.		recessive.

1points

QUESTION 50

1. Fragile X syndrome iscreated by ______ at the end of the X chromosome.

   a.		a non-disjunctionalevent
   b.		a frame shiftmutation
   c.		a nonsensemutation
   d.		a broken DNAstrand
   e.		a series oftrinucleotide repeats

1points

QUESTION 51

1. The inducer of thelac operon is _______, whereas the repressor of thetrp operon is _______.

   	a.	allolactose,tryptophan
   b.		tryptophan,allolactose
   c.		lactose, arabinose
   d.		galactose,tryptophan

1points

QUESTION 52

1. An allele thatexhibits incomplete dominance is usually haplosufficient.

   a.		True
   b.		False

1points

QUESTION 53

1. In the lacoperon in E. coli, a nonsense mutation in the _______ genewill result in a loss of ?-galactosidase activity in the cell.

   a.		lacY
   b.		lacZ
   c.		lacI
   d.		Both B and C arecorrect.

1points

QUESTION 54

1. An individual iscomposed of cells, and these cells should all come from the zygotewhich was formed duting fertilization. Once in a while, we willfind that cells from two different regions of the body may containcells from what must have been 2 different fertilization events,meaning the genotypes for these regions are distinctly different.This is an example of

   	a.	mosaicism
   b.		chimerism
   c.		pleitropy
   d.		non-disjunction
   e.		X-linked dominance

1points

QUESTION 55

1. A testcross oftrihybrid Drosophila produced the following phenotypes and numberof offspring. A table showing phenotype and the number of offspringwith each phenotype is below. A plus sign is used for wild-typephenotype; a letter indicates the mutant phenotype for thatgene.
   
   
   +++ 669
   abc 653
   ++c 121
   ab+ 139
   +b+ 2280
   a+c 2215
   +bc 3
   a++ 2
   Which gene pair is closer together; i.e. there are fewer map unitsbetween them?

   	a.	a --> b
   b.		b --> c
   c.		a --> c
   d.		a --> b and b--> c are the same length
   e.		a --> c and b--> c are the same length
   	f.	Cannot bedetermined