1) One of Mendel's key discoveries is:
a) there are alternate versions of genes called alleles b) a diploid organism has two alleles of each gene
c) there are dominant and recessive alleles
d) Law of Segregation
e) all of the above
2) In pea plant flowers, purple (P) is completely dominant to white (p). If a plant that is true breeding for purple flowers is crossed with a plant with white flowers, what is the expected phenotypic ratio of the offspring?
a) all purple
b) 1 purple : 1 white c) all Pp
d) 1 PP : 1 pp
e) 3 purple : 1 white
3) Which of the following best states Mendel's Law of Segregation?
a) two alleles of one gene do not segregate during meiosis if linked b) two different genes do not segregate during meiosis if linked
c) two alleles of one gene segregate during meiosis
d) two different genes segregate during meiosis
e) this law is difficult to remember no matter how may times we go over it
4) All of the following statements about the genetics of human eye color are true EXCEPT:
a) a person may have two different eye colors due to an error in fetal development b) when melanocytes do not make any pigment the result is usually blue eyes
c) two parents with brown eyes cannot produce a child with blue eyes
d) human eye color is a polygenic trait because more than two genes are involved
5) In cats, black fur is completely dominant to brown fur. You cross two heterozygous parents. If you want to predict the probability of obtaining a heterozygous offspring from this cross you would use:
a) the addition rule because there are two ways of forming a heterozygote
b) the multiplication rule because there are two ways of forming a heterozygote
6) In pea plants, green pods (G) are completely dominant to yellow pods (g). A test cross is done to determine the genotype of a pea plant with green pods. If the test cross results in a ratio of 1 green: 1 yellow, then the genotype of the pea plant in question was:
a) GG b) Gg c) gg
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HINTS/INSTRUCTIONS
• Select the single best answer for each question.
• Mark your final answer on the provided scantron sheet. Multiple choice answers marked on this exam will not be graded, only the scantron sheet will be graded.
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7) If you cross a red cow with a white cow you can get cows with patches of red and patches of white. This is an example of:
a) complete dominance b) incomplete dominance c) codominance
8) In rabbits, the color of body fat is controlled by one gene with two alleles (Y and y). If a yy rabbit is given a standard diet it will have white fat, whereas a yy rabbit given a xanthophyll- free diet will have yellow fat. What is this an example of?
a) epistasis
b) multiple alleles
c) pleiotropy
d) environmental influence e) dosage compensation
9) In snapdragons, red flowers are incompletely dominant to white flowers. A cross of a homozygous red-flowered plant and a homozygous white-flowered plant results in all pink- flowered offspring. If two of the pink-flowered offspring are crossed, the result is 1 red- flowered plant: 2 pink-flowered plants: 1 white-flowered plant. Is this an example of blending?
a) NO b) YES
10) Color blindness is an X-linked recessive condition in humans. A colorblind woman marries a man who can see colors ("normal"). What is the expected genotypic ratio of their offspring?
a) 1 XAXa : XAY
b) 1 XAXa : XaY
c) 1 normal female: 1 colorblind male d) 1: normal female: 1 normal male e)1XAXa :1XaXa :2XaY
11) The pedigree below is for a newly discovered genetic disease. What type of disease is this?
a) a dominantly inherited disease b) a recessively inherited disease
I Seqer + blck circle
^
II black circle + black circle + black sequre
^
III circle
12) For the pedigree shown above, what are the genotypes of the parents in generation II?
a) mother = Aa, father = Aa b) mother = aa, father = aa c) mother = Aa, father = AA d) mother = Aa, father = aa
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13) The separation of homologous chromosomes in anaphase I of meiosis is the physical basis of which of the following?
a) Law of Segregation
b) Law of Independent Assortment
14) The Y chromosome:
a) can be inactivated through tight compaction of the DNA
b) mostly contains genes unrelated to male development
c) has more genes than the X chromosome
d) can be inherited by a male from his maternal grandfather (his mother's father) e) shares a small region of homology with the X chromosome
15) Which of the following statements about linked genes is FALSE?
a) they are inherited together as a unit
b) their linkage is sometimes broken due to crossing over c) they are a part of the same piece of DNA
d) they can be mapped based on recombination frequency e) they assort independently during gamete formation
16) In Drosophila, the genes for body color and wing size are linked. A testcross results in 20 recombinant offspring and 60 parental offspring. The frequency of recombination (Rf) between the genes can be calculated as follows:
a) 20 ÷ 60 = 0.33 b) 60 ÷ 20 = 3.00 c) 20 ÷ 80 = 0.25 d) 60 ÷ 80 = 0.75 e) 20 ÷ 100 = 0.20
17) Turner Syndrome (XO) is caused by monosomy of chromosome X (or the presence of one X chromosome and no other sex chromosome). This is an example of:
a) inversion
b) aneuploidy c) deletion
d) polyploidy
e) translocation
18) Polyploids can be generated through:
a) complete nondisjunction
b) interspecies crosses
c) complete nondisjunction and interspecies crosses
19) Imagine that you repeat Griffith's experiment, and while heat killing the pathogenic S cells you accidentally destroy all of their DNA. What result would you get when you inject a mouse with these heat-killed S cells mixed with live non-pathogenic R cells?
a) the mouse would live because no transformation would occur b) the mouse would live because transformation would occur
c) the mouse would die because transformation would occur
d) the mouse would die because no transformation would occur
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20) The Watson and Crick model of DNA states that:
a) the strands are parallel
b) the nitrogenous bases are on the outside
c) DNA forms a left-handed double helix
d) the bases on opposite strands pair
e) the sugar-phosphate backbone is on the inside
21) Imagine that you repeat the Hershey and Chase experiment to determine whether protein or DNA is the genetic material of a newly discovered virus called CL10. If you find 35S in the pellet obtained after centrifugation what would you conclude?
a) protein is the genetic material of CL10, because the pellet contains the bacterial cells b) DNA is the genetic material of CL10, because the pellet contains the bacterial cells
c) protein is the genetic material of CL10, because the pellet contains the empty phages d) DNA is the genetic material of CL10, because the pellet contains the empty phages
22) Which protein is responsible for relieving tension ahead of the replication fork?
a) primase
b) topoisomerase
c) single strand binding protein d) helicase
e) DNA polymerase
23) What sequence is used to initiate DNA replication?
a) start codon
b) promoter
c) origin of replication
24) Leading strand synthesis:
a) requires several primers
b) occurs away from the replication fork
c) can be proofread by DNA polymerase
d) results in short segments called Okazaki fragments
e) involves the addition of nucleotides to the 5' phosphate group
25) DNA polymerase can only add nucleotides on to a 3' hydroxyl (OH) group.
a) FALSE b) TRUE
26) In eukaryotes, the 5' end of a pre-mRNA is modified by:
a) the addition of a poly(A) tail
b) the removal of introns
c) the addition of a methylated guanine cap
d) nothing because the 5' end of eukaryotic pre-mRNA is not modified
27) The molecule that catalyzes transcription is:
a) RNA polymerase b) DNA polymerase c) spliceosome
d) ribosome
28) Where in a eukaryotic cell does translation occur?
a) nucleus b) cytoplasm
29) All of the following statements about ribosomes are true EXCEPT:
a) they are comprised of large and small subunits b) ribosomal protein plays the catalytic role
c) there are A, P and E sites for tRNA binding
d) they can translocate during elongation
e) Dr. Stanton thinks they are beautiful macromolecules!
30) In which step of translation elongation is the peptidyl-tRNA transferred from the A site to the P site?
a) translocation
b) termination
c) codon recognition
d) peptide bond formation
31) In eukaryotic cells, which of the following allows for rapid translation?
a) coupling of transcription and translation b) targeting by signal peptides
c) the formation of polyribosomes
d) the use of operons
32) A point mutation in the alpha-synuclein gene has been shown to contribute to early-onset Parkinson's disease. In resulting the protein, amino acid 30 is changed from alanine (codon= GCC) to proline (codon=CCC). This is an example of:
a) a silent mutation
b) an insertion
c) a missense mutation d) a deletion
e) a nonsense mutation
33) Cell type specialization is a reason why it is important to regulate gene expression in:
a) prokaryotes
b) eukaryotes
c) all of the above
34) Which of the following can bind to a site near the lac operon promoter and help RNA polymerase initiate transcription?
a) operator b) repressor c) allolactose d) cAMP
e) CAP
35) What will happen when E. coli are grown in the presence of lactose and the absence of glucose?
a) the lac operon will be transcribed
b) the lac operon will not be transcribed
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36) A scientific study published in October 2012 showed that there is no evidence of 30 nm fibers in the mouse genome. If this data is correct, which level of chromatin structure cannot be formed in the mouse genome?
a) nucleosomes
b) looped domains c) beads on a string d) histone proteins
37) When both lactose and glucose are present, all of the following statements are true with regards to the lac operon EXCEPT:
a) some transcription will occur, but not very much b) CAP will be inactive
c) allolactose will bind the repressor
d) cAMP will bind CAP
e) the repressor will not bind the operator
38) What is an enhancer?
a) a transcription factor used for all protein-coding genes
b) a group of protein that mediates interactions between RNA polymerase and other proteins c) a protein that bends DNA to allow transcription activation over long distances
d) a DNA sequence that serves as a distal control element
39) One reason histone acetylation can loosen chromatin structure is that acetyl groups neutralize the positive charge on the histone proteins so they can't bind DNA as tightly.
a) FALSE b) TRUE
40) Eukaryotic gene expression can be controlled post-transcriptionally through all of the following processes EXCEPT:
a) translation
b) chromatin remodeling
c) protein processing
d) transport of mRNA out of the nucleus e) pre-mRNA processing