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HUMAN GENETICS
Exam 3 Study Guide
Week 10: Genetic Testing and Diagnosis
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Explain the difference between genetic testing and genetic screening. What are some
examples in which one or the other would be applicable?
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Be able to intelligently and coherently explain the two following ethical issues with
regards to genetic testing:
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Identification of family members with or at risk for a particular disorder
• Privacy concerns of data
Describe and evaluate the following prenatal tests:
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ultrasound
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amniocentesis
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chorionic villus sampling
• preimplantation genetic diagnosis (PGD)
Describe the cause and risks associated with phenylketonuria (PKU), and explain how
PKU is screened.
Explain why people are screened for certain genetic conditions.
Explain the difference between curing a medical problem and managing or treating the
problem.
Week 11: Molecular Basis for Inheritance
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Briefly explain how X-ray crystallography was used to solve the three-dimensional
structure of DNA.
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Identify the building blocks of
nucleic acids.
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On a figure of a nucleotide (like the
one we labeled in class), be able to
identify the following:
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the phosphate group
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the sugar
• the nitrogenous base
List the four nitrogenous bases
present in DNA.
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List the four nitrogenous bases
present in RNA.
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Explain how individual nucleotides are linked together to form strands of nucleic acid.
Identify the names given to the two different ends of a nucleic acid strand.
Identify which end of a nucleic acid strand new bases are added.
updated 12/27/12
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HUMAN GENETICS
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Exam 3 Study Guide
Explain the attractions that cause two strands of DNA to come together.
Explain what antiparallel means.
Summarize nucleic acids by comparing and contrasting the structures of DNA and
RNA. You should be able to complete the following table:
DNA
RNA
Sugar used in nucleotide
Nitrogenous bases used
Predominantly single- or
double-stranded
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Explain when DNA replication occurs during a cell’s life.
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Explain what is meant by semiconservative replication.
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Explain what is meant by the term gene expression.
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Explain what is meant when we say that the strands of DNA serve as templates during
their replication.
List the steps of replication.
If given a diagram of “incomplete” replication, you should be able to fill in the missing
bases.
Describe the two steps in gene expression including the following:
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Where they occur in the cell
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What the overall purpose of each step is
• What the product of each step is
If provided with a DNA sequence, be able to write out the mRNA from that DNA.
Explain what a codon is.
Be able to use a codon conversion table to translate an mRNA sequence.
Explain the role of ribosomes and amino acids during translation.
Week 12: Mutations
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Compare and contrast mutations with polymorphisms.
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Describe the differences between wild-type alleles and loss-of-function, gain-offunction, and null mutations.
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Be able to explain how wild-type, loss-of-function, gain-of-function, and null alleles
provide the basis for dominant and recessive traits.
Characterize the difference between small- and large-scale mutations, and be able to
provide a possible scenario for each.
updated 12/27/12
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HUMAN GENETICS
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Exam 3 Study Guide
Explain how mutations can occur spontaneously.
List some examples of mutagens.
Describe the following types of mutations:
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Point mutations:
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Missense mutations
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Silent mutations
• Nonsense mutations
Frameshift mutations
Week 13: DNA Forensics
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Define the term forensics, and give examples of different types of forensic data.
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When provided with a list of population frequencies for different STR alleles, you
should be able to calculate the occurrence of a person’s profile in a population (by
multiplying the individual allele frequencies).
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Describe the basis for restriction fragment length polymorphism (RFLP).
Be able to explain the differences between the different ways that we identify unique
patterns in DNA sequences between people: minisatellites, small tandem repeats
(STRs), and single nucleotide polymorphisms (SNPs). Which is the preferred method
and why?
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What are restriction enzymes? What do they do?
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How can using restriction enzymes allow you to distinguish DNA from different
people?
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Describe gel electrophoresis and why scientists use this technique.
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When provided with a diagram of a gel with DNA bands, be able to identify an
individual based on the banding pattern.
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Using the sickle-cell anemia example from class, explain how scientists can identify
genetic disorders using RFLP (restriction fragment length polymorphism) analysis.
Remember: this technique makes use of both restriction enzymes and electrophoresis.
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Be able to provide a list of 3-4 potential sources of DNA for forensic analysis.
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Provide one or two examples of situations in which there is a small amount of DNA
that researchers would want to amplify in order to study.
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List the typical entities or organizations that generally perform DNA profiling for crime
investigations.
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Identify what CODIS is.
Explain what PCR (polymerase chain reaction) is used for, and how primers,
polymerase, and changing the temperature of the reaction result in amplification of a
DNA sequence of interest.
updated 12/27/12
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HUMAN GENETICS
Exam 3 Study Guide
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Be able to discuss controversies associated with criminal DNA profiling, such as the
use of partial matches and whether volunteered samples should be kept forever.
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Explain what a haplogroup is. What is the significance of getting your DNA profiled to
see what haplogroup you belong to?
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