Deck 16: DNA: the Indispensable Forensic Science Tool

Question 1

PCR is a technique that:

A) Provides a statistical analysis of the nitrogenous-base pairings.
B) Can produce many exact copies of segments of DNA.
C) Produces information regarding the sequence of nitrogenous bases.
D) Virtually eliminates operator error from DNA analysis.

Answer 1

B

Question 2

Which nitrogenous base is NOT found in DNA?

A) Thymine
B) Cytosine
C) Uracil
D) Adenine

Answer 2

C

Question 3

Which of the following depicts correct base-pairing in DNA?

A) A-U
B) G-A
C) T-A
D) C-T

Answer 3

C

Question 4

The PCR technique requires the use of a thermal cycler to:

A) Synthesize protein.
B) Copy DNA.
C) Make probes radioactive.
D) Hydrolyze polymerase.

Question 5

The technology of DNA typing had its beginnings in 1985 with the work of:

A) Henry Lee.
B) Francis Crick.
C) James Watson.
D) Alec Jeffreys.

Question 6

In DNA replication,polymerases:

A) Enable the strands to unwind from the helix.
B) Help assemble the new DNA strands in proper base sequence.
C) Separate the strands of the double helix.
D) All of the above

Question 7

The separation of STRs using capillary electrophoresis:

A) Evolved from the flat-gel electrophoresis approach.
B) Decreases analysis time.
C) Is currently the preferred method.
D) All of the above

Question 8

Which is an advantage of working with short DNA fragments?

A) They are more stable and less likely to break apart.
B) Their quantity can be greatly amplified by PCR technology.
C) They are less subject to degradation due to adverse environmental conditions.
D) All of the above

Question 9

The molecular structure of DNA was deduced by:

A) Gregor Mendel.
B) Francis Crick.
C) James Watson.
D) Both B and C

Question 10

The amplification of DNA using the Thermal Cycler takes approximately:

A) 30 cycles.
B) Four cycles.
C) Two hours.
D) Two minutes.

Question 11

CODIS is a national system of:

A) Computers to track the movement of sex offenders released from prison.
B) Shared databases of DNA typing information from convicted felons and crime scene evidence.
C) Vastly enhanced 911 emergency systems.
D) Crime laboratory directors.

Question 12

The discriminating power of mtDNA is ________ the discriminating power of STR analysis.

A) Greater than
B) The same as
C) Less than
D) None of the above

Question 13

In the PCR process,the first step is to heat the DNA strands.This is to permit the:

A) DNA to coil very tightly in the helical shape.
B) Process to take place without DNA degradation.
C) Hybridization to take place.
D) Double-stranded molecules to separate completely.

Question 14

Which component of DNA forms the backbone of the molecule?

A) Phosphate group
B) Nitrogenous base
C) Sugar
D) Both A and C

Question 15

The building blocks of the DNA molecule are known as:

A) Amino acids.
B) Nucleotides.
C) Polysaccharides.
D) Hydrocarbons.

Question 16

Which is NOT a component of a nucleotide?

A) Phosphorous containing group
B) Double helix
C) Sugar
D) Nitrogenous base

Question 17

DNA is a(n):

A) Protein.
B) Starch.
C) Polymer.
D) Enzyme.

Question 18

Which statement is NOT true? Few forensic labs do analysis of mtDNA because:

A) Little mtDNA is present in a cell.
B) The analysis procedure is very rigorous.
C) It costs much more than nuclear DNA profiling.
D) Such study takes a long time.

Question 19

Means to detect the amelogenin gene are included in commercial STR kits used in crime labs because the gene allows determination of:

A) Ethnicity.
B) Blood type.
C) Gender.
D) Eye color.

Question 20

STR analysis has replaced other DNA typing techniques because it:

A) Is less subject to sample degradation.
B) Requires a smaller sample size.
C) Can be implemented using the PCR.
D) All of the above

Question 21

Note that suspect B has only one band in his lane.This is most likely an indication that:

A) He is homozygous for the gene.
B) He is trisomic for the trait.
C) His DNA was contaminated during the collection process.
D) Band shifting occurred.

Question 22

The specific proteins produced by a cell are directly related to the:

A) Sequence of nucleotides in the DNA of the cell.
B) Number of mitochondria in the cell.
C) Length of the chromosomes.
D) Sequence of sugars and phosphates in the cell.

Question 23

Portions of the DNA molecule useful for DNA typing:

A) Code for the production of proteins.
B) Are useful for recombinant DNA.
C) Are repeated many times.
D) Are useful for the production of insulin.

Question 24

The concept of simultaneously extracting,amplifying,and detecting a combination of STRs is known as:

A) PCR.
B) THO1.
C) Multiplexing.
D) Electrophoresis.

Question 25

Which statement about tandem repeats is NOT true?

A) More than 30% of the human genome is composed of these repeating units.
B) Their origin is a mystery.
C) It is thought that they may act as spacers between the coded regions of DNA.
D) They are of no forensic interest.

Question 26

How many different bases are associated with the makeup of DNA?

A) 3
B) 4
C) 5
D) 6

Question 27

Which statement is not correct for Y-STRs?

A) Female STRs will not yield a Y-STR profile.
B) Y-STRs can be amplified by PCR.
C) Y-STR types are typically shorter in length as compared to X-STRs.
D) A typical Y-STR pattern has one band.

Question 28

What is the number of nitrogenous bases needed to code for a specific amino acid?

A) 2
B) 3
C) 5
D) 6

Question 29

The rate at which large DNA fragments move through the electrophoretic gel is ________ the rate at which small DNA fragments move through the same apparatus.

A) The same as
B) Greater than
C) Less than
D) None of the above

Question 30

Which statement regarding STRs is true?

A) Restriction enzymes are used to cut STRs from the DNA helix.
B) There is little variation in the number of repeats from person to person.
C) All humans have the same type of STRs.
D) Typically a core repeat sequence would consist of 15-30 bases.

Question 31

Use this DNA STR pattern of evidence from a rape investigation to answer the following question(s).

The evidence suggests which suspect raped the victim?

A) Suspect A
B) Suspect B
C) Suspect C
D) The evidence shows that none of these suspects is a match.

Question 32

HV1 and HV2 are:

A) Restriction enzymes.
B) STR types.
C) Types of viruses.
D) Regions of mtDNA.

Question 33

Y-STR markers are useful when multiple males are involved in a sexual assault.If three men are involved in such an attack the investigators would expect Y-STR analysis to show a maximum of:

A) Eight peaks.
B) Three peaks.
C) Six peaks.
D) Four peaks.

Question 34

The individuality of an organism is determined by the organism's:

A) DNA nucleotide sequence.
B) Nitrogenous bases.
C) Amino acids.
D) Environment.

Question 35

Which of the following statements about mitochondrial DNA is incorrect?

A) Mitochondrial DNA is located outside the cell's nucleus.
B) Mitochondrial DNA is constructed in a loop configuration.
C) Many copies of mitochondrial DNA's hypervariable regions are made by PCR.
D) The number of repeat segments found in the hypervariable regions are used to type mitochondrialnDNA.

Question 36

Examples of polymers that contain repeating units known as nucleotides are:

A) Hemoglobin.
B) Starch.
C) Cellulose.
D) DNA.

Question 37

In which hereditary disease does abnormal hemoglobin differ from normal hemoglobin by only a single amino acid?

A) Phenylketonuria
B) Hemophilia
C) Sickle-cell anemia
D) Albinism

Question 38

Information from the Human Genome Project will:

A) Help to reveal the role and implications of evolution.
B) Be useful for diagnosing and treating genetic diseases.
C) Reveal the location of a gene on a particular chromosome.
D) All of the above

Question 39

The production of amino acid is coded by a sequence of how many bases on the DNA molecule?

A) Two
B) Three
C) Four
D) Five

Question 40

Assume that two strands of DNA have been separated and that the base sequence on one strand is ATGC.State the sequence of bases on the second strand.

A) GCAT
B) ACTC
C) TGGC
D) TACG

Question 41

How should blood-containing clothes from a victim be packaged?

A) In an airtight metal container
B) In an airtight clear plastic container
C) In a metal paint can
D) In breathable paper after blood has dried

Question 42

Mitochondrial DNA analysis is significantly more sensitive than nuclear DNA profiling.

Question 43

Small amounts of blood are best submitted to a crime laboratory:

A) Immediately while still wet.
B) In a druggists fold.
C) After dried.
D) After removal from surface of deposition and rehydration.

Question 44

The amount of DNA material required for STR analysis is ________ the amount of DNA required for RFLP analysis.

A) The same as
B) Greater than
C) Less than
D) None of the above

Question 45

Each cycle of the DNA Thermal Cycler takes approximately:

A) 30 seconds.
B) Four hours.
C) Two hours.
D) Two minutes.

Question 46

Proteins are formed by linking a combination of nucleotides.

Question 47

James Watson and Francis Crick are credited with discovering the structure of DNA.

Question 48

The greater the number of STRs characterized,the smaller the frequency of occurrence of the analyzed sample in the general population.

Question 49

Electrophoresis can be used in the crime lab to analyze:

A) DNA.
B) Proteins.
C) dried blood.
D) All of the above

Question 50

STRs normally consist of repeating sequences of:

A) 13-17 bases.
B) 18-2 bases.
C) 3-7 bases.
D) 8-12 bases.

Question 51

A typical STR DNA type emanating from a single individual shows a ________ band pattern.

A) One
B) Two
C) Three
D) Zero

Question 52

The four bases on the DNA molecule are paired with A opposite T and G opposite C.

Question 53

A conventional STR profile emanating from a mixture of DNA from male donors yields four peaks or bands for each locus present.How many peaks or bands would you normally expect for each locus if a Y-STR profile is performed on the same sample?

A) One
B) Two
C) Three
D) Four

Question 54

Mitochondrial DNA is found in the nucleus of each cell and is inherited from both parents.

Question 55

As currently performed,DNA-profiling technology cannot provide information helpful in:

A) Matching a suspect to biological evidence found at a crime scene.
B) Deciding immigration cases based on family relationships.
C) Settling matters of questioned paternity/maternity.
D) Determining whether an individual carries a genetic defect.

Question 56

DNA analysts are able to examine samples containing as few as ________ cells for an STR profile.

A) 18
B) 36
C) 180
D) 800

Question 57

A short tandem repeat (STR)is a region of a DNA molecule that contains short segments consisting of 50-100 repeating base pairs.

Question 58

________ region(s)of mitochondrial DNA have been found to be highly variable in the human population for forensic determinations.

A) One
B) Two
C) Three
D) Four

Question 59

Whole blood collected for DNA typing purposes must be placed in a vacuum containing the preservative:

A) Rh factor.
B) EDTA.
C) CODIS.
D) Ethylene glycol.

Question 60

Longer DNA strands are more stable and less subject to degradation than shorter strands.

Question 61

The four bases associated with DNA are adenine,cytosine,guanine,and ________.

Question 62

A ________ is a threadlike structure in the cell nucleus along which the genes are located.

Question 63

Buccal cells are derived from the inner cheek lining.

Question 64

Electrophoresis is widely used in the characterization of proteins and DNA in dried blood.

Question 65

PCR are regions of a chromosome that contain multiple copies of a core DNA sequence arranged in a repeating fashion.

Question 66

Tandem repeats are useful for forensic scientists because they provide a way to distinguish one individual from another through DNA typing.

Question 67

The ________ gene is often used to determine the sex of a DNA contributor.

Question 68

DNA is a large molecule called a polymer,created by linking a series of repeating units known as ________.

Question 69

________ repeats are regions of a chromosome that contain multiple copies of a core DNA sequence arranged in a repeating fashion.

Question 70

Blood in soil must be stored in a clean glass or plastic container and immediately frozen.

Question 71

Decoding the human ________ can be useful for diagnosing and treating genetic diseases.

Question 72

Mitochondrial DNA is arranged in a circular loop of bases while nuclear DNA is arranged in a continuous strand of bases.

Question 73

The more STRs a forensic scientist can characterize,the greater is the likelihood that they originated from two different individuals.

Question 74

The synthesis of new DNA from existing DNA is known as hybridization.

Question 75

Capillary electrophoresis as the preferred technology for characterization of STRs.

Question 76

________ is the molecule that carries the body's genetic information.

Question 77

STR analysis is the most successful and widely used DNA profiling procedure.

Question 78

________ is a technique for replicating or copying a portion of a DNA strand outside a living cell.

Question 79

The Y-STR gene can reveal the sex of the person who contributed a DNA sample.

Question 80

Collection swabs must not be packaged in a wet state.