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Genetics - Final Exam with Solved Questions | BIOL 3301, Exams of Human Genetics

Material Type: Exam; Class: Genetics; Subject: (Biology); University: University of Houston; Term: Spring 2016;

Typology: Exams

2015/2016

Uploaded on 05/15/2016

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BIOL 3301 Genetics Final Exam
All questions are weighted equally and are worth 2 points each
Multiple Choice
1. Between 1976 and 1983, Argentina was governed by a repressive military dictatorship. A
particular aspect of the terror involved kidnapping pregnant women and taking them to
secret detention centers where they were held until they had their babies. After giving
birth, the mothers were killed and the babies were given to families that wanted children
and that had close ties to the government. Political pressures removed the military
government from power in 1983 and the newly elected president established a
commission to investigate the fates of the disappeared. Mitochondrial DNA analysis was
used on the kidnapped babies and their
a) Maternal grandfather
b) Maternal grandmother
c) Paternal grandfather
d) Paternal grandmother
2. You are given a human pedigree for a genetic disorder. You notice that none of the
females are afflicted by the disorder whereas around 50% of the males are afflicted. What
is the most likely mode of inheritance?
a) Autosomal dominant
b) Autosomal recessive
c) X-linked recessive
d) X-linked dominant
e) Y-linked dominant
3. You perform a dihybrid cross between two plants with purple flowers and yellow seeds
(WwGg). What is the probability that a randomly sampled offspring is homozygous for
both recessive alleles, given that it has purple flowers and yellow seeds?
a) 0
b) 1
c) ¼
d) 1/9
e) 1/16
4. A gene controlling fruit size in a tomato has two alleles L and S. You cross a large LL
homozygote with a small SS homozygote and observe all medium fruit size in the F1
offspring. When you cross the F1 heterozygotes, what phenotypic ratio do you expect in
the F2 progeny?
a) 1:1 big:small
b) 3:1 big:small
c) 3:1 big:medium
d) 1:1:1 big:medium:small
e) 1:2:1 big:medium:small
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BIOL 3301 Genetics Final Exam

All questions are weighted equally and are worth 2 points each

Multiple Choice

  1. Between 1976 and 1983, Argentina was governed by a repressive military dictatorship. A particular aspect of the terror involved kidnapping pregnant women and taking them to secret detention centers where they were held until they had their babies. After giving birth, the mothers were killed and the babies were given to families that wanted children and that had close ties to the government. Political pressures removed the military government from power in 1983 and the newly elected president established a commission to investigate the fates of the disappeared. Mitochondrial DNA analysis was used on the kidnapped babies and their a) Maternal grandfather b) Maternal grandmother c) Paternal grandfather d) Paternal grandmother
  2. You are given a human pedigree for a genetic disorder. You notice that none of the females are afflicted by the disorder whereas around 50% of the males are afflicted. What is the most likely mode of inheritance? a) Autosomal dominant b) Autosomal recessive c) X-linked recessive d) X-linked dominant e) Y-linked dominant
  3. You perform a dihybrid cross between two plants with purple flowers and yellow seeds (WwGg). What is the probability that a randomly sampled offspring is homozygous for both recessive alleles, given that it has purple flowers and yellow seeds? a) 0 b) 1 c) ¼ d) 1/ e) 1/
  4. A gene controlling fruit size in a tomato has two alleles L and S_._ You cross a large LL homozygote with a small SS homozygote and observe all medium fruit size in the F 1 offspring. When you cross the F 1 heterozygotes, what phenotypic ratio do you expect in the F 2 progeny? a) 1:1 big:small b) 3:1 big:small c) 3:1 big:medium d) 1:1:1 big:medium:small e) 1:2:1 big:medium:small
  1. A female who is a carrier for hemophilia has 6 sons. What is the probability that 3 of her sons will have inherited this disease? P(x1, x2) = N!/(x1! X x2!)X(px1qx2) a) ½ b) 6/ c) 20/ d) 6/
  2. One gene affecting multiple phenotypes is known as a) Incomplete dominance b) Pleiotropy c) Epistasis d) Gene by environment interactions
  3. When we say mutations are complimenting each other, we mean a) The mutations are occurring on different genes b) The mutations are on the same gene c) The mutations are working together to greatly affect the phenotype d) None of the above
  4. True-breeding parents (AAbb and aaBB) are crossed. A test cross of the F1 produces the progeny ratios of 0.15 AB, 0.17 ab, 0.34 Ab, 0.34 aB. How far apart are the A and B genes? a) 15 map units b) 32 map units c) 34 map units d) 68 map units
  5. Genetic interaction in the methionine biosynthesis pathway is shown below. Met B null mutants need to be supplemented with which molecule? a) Homoserine b) Cysteine c) Cystathionine d) Homocysteine
  6. You perform a dihybrid cross between two plants with yellow, smooth seeds ( GgRr ). By comparing your observed and expected offspring counts for each phenotypic class, you

d) G and T

  1. In a bacterial gene, where is the promoter located? a) Upstream of the transcription termination site b) Downstream of the transcription termination site c) Upstream of the transcription start site d) Downstream of the transcription start site e) Within the transcribed region
  2. Which of the following is a characteristic of RNA splicing in Eukaryotes? a) It involves recognition of sequence-specific intron/exon boundary sites by a spliceosome b) Exon/intron boundaries are typically characterized by stop codons c) It involves removal of introns from a gene sequence followed by transcription and subsequent splicing of exons. d) After splicing occurs, the RNA polymerase complex removes remaining exons for degradation.
  3. Which of the following statements about ribosomal translation is true? a) During translational elongation, peptidyl transferase mediates the formation of a peptide bond between amino acids occupying the A site and P site of the ribosome b) Initiator tRNA is only found in the P site of the ribosome c) Deacylated tRNA is found in the E site of the ribosome d) All of the above
  4. Tight packaging of eukaryotic chromosomes are mediated by proteins such as a) Histones b) Small nucleoid-associated proteins c) Structural maintenance of chromosome (SMC) proteins d) A and B e) B and C
  5. If an organism has three more or sets of chromosome in each nucleus it is a) Haploid b) Diploid c) Aneuploid d) Polyploid
  6. Occasionally, a piece of chromosome breaks off and sticks to a non-homologous chromosome without a reciprocal event. This is known as: a) Unbalanced translocations b) Reciprocal balanced translocations c) Robertsonian translocations d) Paracentric inversion e) Pericentric inversion
  1. Over the course of human evolution, brain size has steadily increased. Which of the following statements most likely explains this phenomenon? a) The most common recent ancestor of chimps and humans had the cognitive capacity to engage in cooking b) Cooking allowed more energy to be extracted from food and less energy expended in processing it. c) Eating cooked food led to the evolution of a smaller gut d) Having a smaller gut allowed for more energy to be diverted into maintaining a larger brain e) All of the above
  2. A mutation in which a codon is changed to a premature stop codon that results in truncation of the resulting protein is known as a: a) Nonsense mutation b) A silent mutation c) A frameshift mutation d) A missense mutation
  3. Which of the following statements regarding mutations is/are true? a) Mutations are random changes to DNA sequence caused by replication errors, chemicals, or radiation b) Spontaneous mutation rates are generally low c) Cells have DNA repair genes that identifies and corrects damage to the DNA molecules d) A and C only e) A, B, and C
  4. One pure culture of bacteria has mutations for leucine and arginine while another pure culture has mutations for histidine and valine. When you combine these strains via conjugation and create a new strain capable of growing on minimal media, what is most likely to be true of the new strain? a) It carries wildtype copies of leucine, arginine, histidine and valine b) It carries mutant copies of leucine, arginine, histidine and valine c) It carries wildtype copies of leucine and arginine but mutant copies of histidine and valine d) It carries mutant copies of leucine and arginine but wildtype copies of histidine and valine
  5. Negative control involves the binding of a repressor to the operator to prevent transcription. If an inducer molecule is present, it binds to the repressor and changes its conformation so that it is unable to bind to the operator. This allows for expression of the operon. For the lac operon, the inducer molecule is: a) cAMP b) allolactose c) β-galactosidase d) lactose permease

a) It is known that pieces of DNA that are located near each other on a chromosome tend to be inherited together. b) DNA between related individuals will have similar sequences. c) Homozygous DNA do not provide any useful information. d) All of the above

  1. Body axes and segment formation in drosophila is controlled through the interaction of various genes. Some of these genes are known collectively as “gap genes” whose function is to: a) Define the anterior-posterior axis of the embryo. b) Define broad regions of the embryo. c) Define the segments of the embryo. d) Define the anterior-posterior regions of each segment.
  2. Several maternally deposited transcription factors help define the anterior-posterior axis of the embryo. One such factor, nanos , has the highest concentrations toward the posterior end of the embryo. What is the phenotype of the offspring of a mother who is homozygous for a nanos loss of function mutation? a) Loss of posterior regions of the embryo and replacement with duplicated anterior regions. b) Loss of anterior regions of the embryo and replacement with duplicated posterior regions. c) Loss of thoracic regions resulting in a shorter embryo. d) Loss of posterior abdominal regions resulting in a shorter embryo.
  3. During vulva development in C. elegans, an anchor cell sends an inductive signal to the primary vulva precursor cells. The primary vulva precursor cells sends inhibitory signals to the secondary vulva precursor cells. What is the phenotype of a worm that has a mutation knocking out the receptors on the primary vulva precursor cells? a) Multiple vulvas because multiple primary precursor cells are induced. b) Multiple vulvas because no inhibitory signal is sent to the secondary precursor cells. c) One vulva because the primary precursor can still send the inhibitory signal to the secondary cells. d) No vulvas because the anchor cell cannot induce the primary precursor cell. e) No vulvas because the primary precursor cell cannot induce the secondary cells.
  4. In an experiment examining the inheritance of a continuous trait, fruit size, two sets of pure bred parents are crossed to each other. Which of the following statements is/are true? a) The F1 hybrid offspring will have an intermediate fruit size between the parents. b) The F2 offspring will have the same mean as the F1 but more variance. c) The F2 offspring will have the same mean and variance as the F1. d) A and B e) A and C
  1. Phenotypic variance is the result of genetic and environmental variation. Pure-breeding lines produce an F1 that is selfed to produce an F2. Which of the following statements about phenotypic variance is true? a) Both parental lines are genetically uniform and any variation that exist in the parental populations are entirely due to environmental factors. b) F1 hybrids have no genetic variation and all phenotypic variation is caused by the environment. c) Phenotypic variation in F2 hybrids is caused by genes and the environment. d) All of the above
  2. Twins have been used to study the heritability of traits. This involves comparing Monozygotic (MZ) and Dizygotic (DZ) Twins raised together vs. apart from each other. If phenotypic variation for the ability to snap one’s fingers was entirely genetic, which of the following statements would be true? a) Concordance for both monozygotic and dizygotic twins would be 50–100%. b) Concordance for monozygotic and dizygotic twins would be less than 50%. c) Concordance for dizygotic twins would be 50 %. d) Concordance for dizygotic twins would be approximately 100%.
  3. A population is said to be in Hardy-Weinberg Equilibrium if a) p+q= b) p^2 +2pq+q^2 = c) Allele frequencies are not changing from one generation to the next d) Phenotypic frequencies are not changing from one generation to the next e) All of the above
  4. A gene has two alleles (A1 and A2). The frequency of A1 is 0.4. What is the expected frequency of the A2A2 genotype? a) 0. b) 0. 36 c) 0. d) 0. e) 1
  5. The average birth weight of a human baby is 3.5 kg (7.7 lb) though the range of being normal is between 2.5 and 5 kg (all but 5% of newborns will fall into this range). Over the course of human evolution, nature has selected against extremely large and extremely small babies. This is known as: a) Directional selection b) Negative frequency dependent selection c) Disruptive selection d) Stabilizing selection
  6. Which of the following processes is least likely to change allele frequencies? a) Non-random mating b) Finite population size (genetic drift)

a. True b. False

  1. Gene flow can never equalize allele frequencies between two populations. a. True b. False
  2. (has no point value) What is the color of your exam?

a. White b. Blue c. Green d. Yellow