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REVIEWExam Three

QUESTION 1 A mother and father are

phenotypically normal, but their child has an inherited metabolic disorder. What is the chance that their next child will have this disorder?

a) 0b) ½c) ¾d) ¼e) 1

QUESTION 2 What does the law of segregation say?

What does the law of independent assortment say?

QUESTION 3 If you have a single gene that affects

more than one trait, this is an example of…

a) polygenic inheritanceb) epistasisc) pleiotropyd) nondisjunctione) a and c

QUESTION 4Distinguish between complete

dominance, codominance, and incomplete dominance. What is the phenotypic ratio for each if I cross Tt x Tt?

QUESTION 5 A plant that is true-breeding for a

dominant trait is crossed with a plant that is true breeding for a recessive trait. The offspring plant is then allowed to self-pollinate. What is the phenotypic ratio of this new cross?

a) 1:2:1b) 3:1c) 9:3:3:1d) 1:1e) None of the above

QUESTION 6 Cystic Fibrosis is caused by a

defective allele that…

a) causes hemoglobin molecules to malfunction

b) encodes a dysfunctional enzyme that fails to break down brain lipids

c) encodes a neurotoxind) encodes an enzyme that breaks down

muscle fiberse) none of the above

QUESTION 7 A TTFF individual will produce ______

types of gametes, but a TtFf individual will produce ______ types of gametes.

a) one, fourb) four, onec) two, oned) three, twoe) two, three

QUESTION 8 Which of the following would be the

first/fastest to allow us to get genetic information about the fetus?

a) chorionic villus samplingb) amniocentesisc) ultrasoundd) a or be) a and c

QUESTION 9 If my brother has thalassemia, but I

don’t, and neither of our parents have thallassemia, what is the chance that I am a carrier of the disease?

a) ¼b) 1/3c) ½d) 2/3e) ¾

QUESTION 10 We do not know the genotype of one

parent. Assume white is recessive to red(red= R, white = r). If a test cross is done with the unknown parent resulting in half red offspring and half white offspring, what is the genotype of the unknown parent?

a) RRb) Rrc) rrd) any of these are possiblee) a or c are possible

QUESTION 11 If a species shows incomplete

dominance for a single trait, the genotype and phenotype will be

a) differentb) equalc) indeterminantd) none of the abovee) a and b

QUESTION 12 If two tall parents give birth to a child

with achondroplasia, it is most likely the result of…

a) both parents passing a recessive geneb) both parent passing a dominant genec) a new mutationd) new expression of a previously dormant

genee) none of the above

QUESTION 13 What is the chance of having an

offspring that has blood type A if the parents are type AB and O.

a) ½b) ¼c) 1/3d) Nonee) All will be A

QUESTION 14 If the couple in question 13 (parents

have type AB and O blood) had a second offspring what is the chance that it will have blood type A?

a) ½b) ¼c) 1/3d) 0e) 1

QUESTION 15 If 56 offspring are red-green, 456 are

red-red, 44 are red-blue, and 444 are blue-blue; what is the recombination frequency?

a) 15%b) 24%c) 20%d) 5%e) 10%

QUESTION 16 If the cheek cells from an individual

with Klinefelter’s were viewed under a microscope, the person would appear to be

a) maleb) femalec) indeterminated) a or ce) none of the above

QUESTION 17 The chromosomes in mitochondria

are most like

a) the somatic chromosomes of the fatherb) the somatic chromosomes of the motherc) the chromosomes of a bacteriad) a and ce) b and c

QUESTION 18If my phenotypic ratio is 9:7 or 9:3:4 following

the cross of BbCc x BbCc, which of the following is most likely happening?

a) Codominanceb) Complete dominancec) Epistasisd) Polygenic inheritance e) Incomplete dominance

QUESTION 19 If a father has an x-linked recessive

disorder, but the mother does not have the disease and is not a carrier, what is the possibility that a son will have this disorder?

100%25%50%0%None of these

QUESTION 20Describe the following conditions and then

classify all the following (autosomal dominant, autosomal recessive, x-linked recessive, etc.):

a) Color blindnessb) Cystic fibrosisc) Huntington’s diseased) Polydactyly e) Albinism f) Duchenne muscular dystrophyg) Thalassemia h) Tay-Sachs disease

QUESTION 21 Cells that have more than two

complete sets of chromosomes are called….

a) aneuploidb) trisomyc) polyploidd) tetrasomye) none of these

QUESTION 22 If alleles are 5% recombinant, then

they are _____ map units apart.

a) 50b) 25c) 10d) 100

e) None of the above

QUESTION 23T/F The most common phenotype is referred to as the

dominant type.

QUESTION 24 In werewolves, pointy ears (P) are dominant

over round ears (p). The gene is on the X chromosome. Werewolves use the same sex determining system as humans. A female werewolf has pointy ears even though her father has round ears. What percentage of her sons will have round ears if she marries a werewolf with round ears?

a) 0%b) 25%c) 50%d) 75%e) 100%

QUESTION 25 Okazaki fragments are eventually

joined by

a) DNA polymeraseb) primasec) topoisomrased) helicasee) None of the above

QUESTION 26What is nuclease?

QUESTION 27 If there is 23 % adenine in a double

helix of DNA, how much cytosine is there?

a) 23%b) 46%c) 27%d) 54%e) None of the above

QUESTION 28 Which of the following statements is

incorrect?

a) double-stranded DNA is helical.b) DNA contains phosphodiester linkages.c) Double-stranded DNA has two

complementary strandsd) Adenine and uracil are present in equal

amounts in double-stranded DNA.e) All are true.

QUESTION 29 Which of these is the correct

sequence of enzymes used in the synthesis of the lagging strand of DNA?

a) primase, helicase, polymerase, ligaseb) helicase, primase, ligase, polymerasec) helicase, primase, polymerase, ligased) helicase, polymerase, primase, ligasee) ligase, primase, polymerase, helicase

QUESTION 30 T/F The replication fork is also known as the origin

of replication.

QUESTION 31 In RNA, ______ are removed so that

transcription can occur.

a) intronsb) exonsc) errorsd) a and ce) none of the above

QUESTION 32The codons AAA, CCC, GGG, and UUU

specify the amino acids lysine, praline, glycine, and phenylalanine, respectively. Which of the following DNA sequences would specify the peptide pro-gly-lys-phe if present in the template strand?

a) 3’-CCCGGGAAATTT-5’b) 3’-CCCGGGAAAUUU-5’c) 5’-GGGCCCUUUAAA-3’d) 5’-GGGCCCTTTAAA-3’e) None of these

QUESTION 33 When a single base pair is either

inserted or deleted from DNA it results in a ______.

a) nonsense mutationb) frame-shift mutationc) inversion mutationd) translocation mutation

e) missense mutation 

QUESTION 34 How many amino acids would be

present in the polypeptide created from the mRNA sequence AUGCCCAUUGCUUGAGGGAUGUAA.

a) 4b) 5c) 6d) 7e) 8

QUESTION 35 The fact that GGU, GGC, GGA, and

GGG all code for the same amino acid is a good example of

a) transcriptionb) wobblec) nonsense codonsd) a or ce) all of these

QUESTION 36 Protein synthesis requires all of the

following except ______.

a) ribosomesb) mRNAc) tRNAd) amino acidse) endoplasmic reticulum

QUESTION 37 The central dogma of genetics is

a) DNA to amino acids to RNAb) DNA to transcription to RNAc) Protein to RNA to DNAd) DNA to RNA to Proteine) None of the above

QUESTION 38 A group of 1200 nucleotides could

code for _____ amino acids.

a) 200b) 600c) 400d) 300e) None of the above

QUESTION 39 What is the proper order of these events?

translation RNA processing transcription modification of protein

a) 1,2,3,4b) 3,2,1,4c) 4,2,3,1d) 2,3,4,1e) 1,2,4,3

QUESTION 40 T/F The poly-A tail binds to the small

ribosomal subunit to allow the codons to be read from the proper starting point.

QUESTION 41 The sex determining system where

the female is heterozygous and the male is homozygous is referred to as the _____ system.

a) ZWb) XYc) XOd) Haplo-diploide) None of these

QUESTION 42 Vampires can have a widows peak (W) or a

continuous hairline(w), and can have red (r) or white eyes (R). Widows peak and red eyes are the most common. Cross a vampire that is homozygous for both wild types with a vampire that is heterozygous for both traits. How many offspring will be continuous hairline white eyes?

a) Noneb) Allc) 1d) 8e) 12

QUESTION 43 Use the cross from number 42. How

many offspring show traits for widows peak and white eyes?

a) Noneb) Allc) 1d) 8e) 12

QUESTION 44 If a plant this is heterozygous for

flower position and stem length (AaTt) self-pollinates, and 800 seeds are planted, how many plants should be Tall with Axial flowers?

a) 450b) 150c) 50d) 100e) None of the above

QUESTION 45 A family of 15 people with genes for

brown eyes only has 11 family members with brown eyes. What is the penetrance of brown eyes in this family?

a) 27%b) 33%c) 92%d) 73%e) 12%

QUESTION 46Describe RNA processing in as much

detail as Dr. Cusic did in lecture.

QUESTION 47 If two parents are both carriers of an

autosomal recessive disease how likely is it that they would have a male offspring with the disease?

a) ½b) ¼c) 1/3d) 2/3e) None of the above

QUESTION 48 If the P generation crosses a true

breeding brown haired (B) person with a true breeding blond(b), what will the genotypic ration of the F2 generation be?

a) 3:1b) 1:2:1c) 9:3:3:1d) A or ce) None of these

QUESTION 49 DNA replication is a:

a) Dispersive processb) Conservative processc) Semi-conservative process

QUESTION 50 Transcription is initiated when RNA

polymerase binds to

a) A promoterb) An initiator c) A transcriptord) A codone) None of the above

QUESTION 51 The promoter sequence in eukaryotes is

(included) in which of the following:

a) TAATAAb) TATAAAc) TTGACAd) GTTAAAe) None of the above are correct

QUESTION 52 The direct result of transcription is

a) A duplicate DNA moleculeb) nRNAc) A proteind) mRNAe) None of the above

QUESTION 53 The direct result of translation is

a) A duplicate DNA moleculeb) nRNAc) A proteind) mRNAe) All of the above

QUESTION 54 In messenger RNA, the nucleotide series

UAG specifies

a) Arginineb) Serinec) Startd) Stope) Proline

QUESTION 55Base-pair substitutions involving the third

base of a codon are unlikely to result in an error in the polypeptide. This is because:

a) Substitutions are corrected before transcription begins.

b) Substitutions are restricted to introns.c) The base-pairing rules are less strict for the

third base of codons and anticodons. d) A signal-recognition particle corrects coding

errors.e) Transcribed errors attract snRNPs, which then

stimulate splicing and correction.

QUESTION 56The anticodon of a particular tRNA

molecule is

a) Complementary to the corresponding mRNA codon

b) Complementary to the corresponding triplet in rRNA

c) The part of tRNA that bonds to a specific amino acid

d) Changeable, depending on the amino acid that attaches to the tRNA

e) Catalytic, making the tRNA a ribozyme

QUESTION 57If a particular operon encodes enzymes for

making an essential amino acid and is regulated like the trp operon, then

a) The amino acid inactivates the repressorb) The enzymes produced are called inducible

enzymesc) The repressor is active in the absence of

the amino acidd) The amino acid acts as a co-repressore) The amino acid turns on transcription of the

operon

QUESTION 58What would occur if the repressor of an

inducible operon were mutated so it could not bind the operator?

a) Continuous transcription of the operon’s genes

b) Reduced transcription of the operon’s genesc) Buildup of a substrate for the pathway

controlled by the operond) Irreversible binding of the repressor to the

promotere) Overproduction of catabolite activator protein

(CAP)

QUESTION 59In E. coli, tryptophan switches off the trp

operon by

a) Inactivating the repressor proteinb) Inactivating the gene for the first enzyme

in the pathway by feedback inhibition c) Binding to the repressor and increasing

the latter’s affinity for the operatord) Binding to the operatore) Binding to the promoter

QUESTION 60Inducible enzymes

a) Are usually involved in anabolic pathwaysb) Are produced when a small molecule

inactivates the repressor proteinc) Are produced when an activator molecule

enhances the attachment of RNA polymerase with the operator

d) Are regulated by inherently inactive repressor molecules

e) Are regulated almost entirely by feedback inhibition

GOOD LUCK STUDYING!