Heredity and Genetics Quiz                       



  1. A karyotype of a human could be expected to show:
  2. a) 46 chromatids, from 23 homologous chromosome pairs
  3. b) any non-disjunction mutations, such as trisomy and monosomy
  4. c) the mutation of a single nucleotide in the DNA sequence
  5. d) both a and b


  1. If two parents, one of blood type A and one of type B, have a type-O child, what must

     be true?

  1. a) one of the parents must be heterozygous with a i allele, that is IAi or IBi
  2. b) this is not possible
  3. c) both parents must be heterozygous
  4. d) a mutation occurred


  1. Pleiotropy refers to:
  2. a) multiple alleles each having partial control of one trait
  3. b) the control of more than one trait by a single allele
  4. c) multiple alleles having co-dominant control of a trait
  5. d) the tendency for alleles on the same chromosome to be inherited together


  1. Imagine Mendel crosses a homozygous dominant round-seeded pea plant (RR) with a heterozygous plant (Rr). What phenotypic ratio would occur in the F1 generation?
  2. a) all round
  3. b) 3 round : 1 wrinkled
  4. c) 1 round : 1 wrinkled
  5. d) all wrinkled


  1. Mendel’s colleague, Brother Cadfael, wants one of the F1 offspring from #4, but needs to know its genotype. What could Mendel do to find this out?
  2. a) cross it with a homozygous dominant plant
  3. b) cross it with a homozygous recessive plant
  4. c) cross it with another F1 Plant
  5. d) wait until it produces seeds


  1. Mendel’s law of independent assortment:
  2. a) is not true in all circumstances, given what we know of modern genetics
  3. b) states that different alleles for the same trait assort independently
  4. c) states that alleles for different traits assort independently
  5. d) both a and c


  1. A male with Jacob’s syndrome (having an XYY genotype) could be the result of:
  2. a) non-disjunction of the Y chromosome during the first meiotic division
  3. b) non-disjunction of the Y chromosome during the second meiotic division
  4. c) non-disjunction in either the mother or father
  5. d) both b and c


  1. For a sex-linked trait located on the human X chromosome:
  2. a) males will always express the allele inherited from their mothers, being

homozygous for this

  1. b) females may be homozygous or heterozygous for a triat, but randomly express

only one allele

  1. c) females always express the dominant allele
  2. d) both a and b


  1. Which of the following were inaccuracies of Mendel’s genetic model?
  2. a) Mendel concluded that alleles for all traits assort independently
  3. b) it did not account for traits influenced by multiple alleles
  4. c) it did not account for the influence of environment on phenotype
  5. d) all of the above


  1. You observe that a population of Dryas occidentalis growing on top of a mountain (population A) produces plants with smaller leaves than those growing at a lower elevation (pop. B). To find out whether this is an environmental influence on phenotype, what would you do?
  2. a) cross-breed plants from populations A and B in a greenhouse
  3. b) locate a pure-breeding strain, C, and cross-breed it with A and B
  4. c) collect seeds from several plants in populations A & B, and grow them in a

controlled environment

  1. d) any of these would work


  1. d
  2. c
  3. b
  4. a
  5. b
  6. d
  7. b
  8. d
  9. d
  10. c


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Multiple choice answers are in bold.


  1. Which of the following pairs of bases has three hydrogen bonds to hold them together?
  2. a) A and T
  3. b) A and G
  4. c) C and A
  5. d) C and G
  6. e) none of the above


  1. List three factors that can cause DNA to denature.

Heat, changes in pH(alkaline conditions), chemicals


  1. Which of the following statements is true regarding the 3D structure of DNA?
  2. a) The A form is found in all living cells.
  3. b) The Z form forms a left handed helix.
  4. c) The Z form has been found in some living cells.
  5. d) A and B
  6. e) B and C


  1. You examine the genomic structure applying the technique of DNA reassociation kinetics. In the table below, the three samples are listed, as well as the times it took for each sample to reassociate (renature). 


                Sample                                                  Time

                gorilla DNA                                          55 seconds

                fruit fly DNA                                        35 seconds

                yeast DNA                                             15 seconds


What conclusions can you draw about the structure of the genomic DNA of these samples based on this data? Reassociation kinetics describes the complexity of a given piece of DNA: repetitive sequences renature faster than unique sequences.  The gorilla contains the most unique sequences of the group, since its time to renature is longer than the other two.  The yeast represents the DNA whose sequences are most repetitive.


  1. Compare and contrast nucleotides and nucleosides.

Structural question: Nucleosides and nucleotides both contain the nitrogenous base and specific sugar.  The nucleotide is the only one that has the additional phosphate group attached.


  1. Draw how the base adenine interacts with the base thymine ( for this question, you will need to draw the bases and indicate hydrogen bonds, if appropriate).

From your notes and other texts.  If you have questions on this, please see me.


  1. We discussed the Meselsohn-Stahl experiment in class. Predict what products would be generated by conducting the Meselsohn-Stahl experiment under the following conditions (note:  you can assume in all cases that the bacteria have been raised on a 14N environment and that replication is semi-conservative):


  1. a) if the bacteria went through one life cycle in a 14N environment, and then a second life cycle in a 15N environment. After one cycle in 14N, all products would be 14N, and the band would migrate in the light (top) position. After the second cycle, you would see all hybrid products, migrating between the 14N “light” and the 15N “heavy”.
  2. b) if the bacteria went through one life cycle in a 15N environment All products would be hybrid.
  3. c) if the bacteria went through one life cycle in a 15N environment, and then a second life cycle in a 14N environment After the first cycle, all products would be hybrid (14N and 15N). After the second cycle, you would see both hybrid products and light 14N products.


  1. Describe the functions of the following enzymes:
  2. a) DNA primase: lays down the RNA primers needed for DNA polymerase to start
  3. b) DNA ligase: attaches the fragments from leading and lagging strands together on the replication bubble
  4. c) DNA polymerase: synthesizes DNA from 5’ to 3’
  5. d) DNA helicase: unwinds the helix to allow DNA polymerase to synthesize on both leading and lagging strands


  1. Define the three classes of satellite DNA, and explain the characteristics of each class.


  1. For the following restriction enzymes, write out the specific sequence they recognize, and indicate whether they cut DNA with a 5' overhang, a 3' overhang, or a blunt cut (note: you must look up this information, and there are many site and catalogs that have this information):
  2. a) EcoRI : 5’ overhang b) BamHI: 5’ overhang c) EcoRV : blunt   d) PstI : 3’ overhang  e) XhoI 5’ overhang

You won’t need to memorize RE sites for the exam.  However, you need to know how to identify if given information about how the enzyme cuts. 


  1. Describe the role of each chemical in isolating DNA:
  2. a) Detergent: helps solubilize lipids in cell membrane and nuclear membrane
  3. b) Salt: helps precipitate DNA by causing aggregation; also helps destabilize membranes
  4. c) Ethanol : DNA is insoluble in ethanol, so adding ethanol allows for precipitation
  5. d) Phenol/Chloroform (Organics): helps remove soluble proteins from DNA preparations


  1. You have a plasmid with the following properties:a) an origin of replication and b) the AmpR gene (ampicillin resistance gene)


You transform this plasmid into bacteria, and plate the transformation mix on nutrient agar plates.  For each plate listed below, describe what bacteria would grow on the plate (ex: no bacteria, a lawn, colonies).


1) transformation + plasmid plated on regular nutrient agar plates (ex LB plates): a lawn; all bacteria should grow, whether or not they have the plasmid

2) transformation + plasmid plated on nutrient agar plates with ampicillin.: selection of only those bacteria with plasmid; appears as colonies

3) transformation without plasmid  plated on nutrient agar plates with ampicillin : nothing: bacteria without plasmid should die in the presence of ampicillin


  1. You find a fuzzy, nonspecific smear at the bottom of your agarose gel. What could account for the presence of this smear?  Two possible answers (there are probably more…): degraded DNA migrates as a smear, but RNA also migrates as a smear in the same position.


  1. You conduct a restriction mapping experiment on a circular piece of DNA which is 1000 bp. When you cut this piece of DNA with a set of restriction endonucleases, you obtain the following fragments:

                                EcoRI:   200, 800

                                XbaI:     1000

                                BamHI: 1000

                    EcoRI+ XbaI: 50, 200, 750

                    Xba I + BamHI: 1150, 850


Use this information to construct a map with the location of each restriction site for each enzyme listed above.  ( If you can't do this on the computer, you can turn in the map separately.)


Answer: this is hard for me to draw electronically, so I will describe: There are two sites for EcoRI, and one site each for Xba and Bam.  The Eco RI sites are on the circle, 200 bp apart.  The Xba site is 50 bp away from one of the EcoRI sites (not in between them).  The Bam site is 150 bp away from the Xba site, but you can’t tell on which side because you are missing information in this question.

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