Deck 9: Firearms, Toolmarks, and Other Impressions

Question 1

Which component of DNA forms the backbone of the molecule?

A) phosphate group
B) nitrogenous base
C) sugar
D) adenine
E) both A and C

Answer 1

E

Question 2

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
E) B and C only.

Answer 2

B

Question 3

When using a three-probe system of DNA typing, what is the maximum number of bands a typical DNA pattern will show?

A) 3
B) 16
C) 6
D) 9
E) 12

Answer 3

C

Question 4

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

A) number of mitochondria in the cell.
B) length of the chromosomes.
C) sequence of sugars and phosphates in the cell.
D) sequence of nucleotides in the DNA of the cell.
E) size of the cell.

Question 5

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

A) environment.
B) decisions.
C) nitrogenous bases.
D) DNA nucleotide sequence.
E) amino acids.

Question 6

The building blocks of the DNA molecule are known as:

A) nucleotides.
B) hydrocarbons.
C) purines.
D) polysaccharides.
E) amino acids.

Question 7

The molecular structure of DNA was deduced by:

A) Linus Pauling.
B) Francis Crick.
C) James Watson.
D) Gregor Mendel.
E) both B and C

Question 8

Which statement about RFLPs is NOT true?

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

Question 9

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

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

Question 10

Which nitrogenous base is NOT found in DNA?

A) cytosine
B) uracil
C) guanine
D) adenine
E) thymine

Question 11

Restriction enzymes:

A) reduce the time required for PCR.
B) limit the amount of protein produced in a cell.
C) cut DNA at specific sites.
D) reduce the DNA replication rate.
E) inhibit DNA replication.

Question 12

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

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

Question 13

Which statement about tandem repeats is NOT true?

A) It is thought that they may act as spacers between the coded regions of DNA.
B) Their origin is a mystery.
C) They are of no forensic interest.
D) More than 30% of the human genome is composed of these repeating units.
E) More than one STR can be analyzed at once in a process called multiplexing.

Question 14

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

A) phenylketonuria
B) cystic fibrosis
C) sickle-cell anemia
D) hemophilia
E) albinism

Question 15

DNA is a(n):

A) polymer.
B) enzyme.
C) starch.
D) sugar.
E) protein.

Question 16

Recombinant DNA technology is useful in producing:

A) artificial hearts and kidneys.
B) insulin and growth hormone.
C) new organs for transplant.
D) livestock.
E) clones.

Question 17

PCR is a technique that:

A) virtually eliminates operator error from DNA analysis.
B) can produce many exact copies of segments of DNA.
C) produces information regarding the sequence of nitrogenous bases.
D) provides a statistical analysis of the nitrogenous-base pairings.
E) all of the above

Question 18

Which is NOT a component of a nucleotide?

A) sugar
B) nitrogenous base
C) phosphorous containing group
D) double helix
E) all of the above

Question 19

Information from the Human Genome Project will:

A) help to reveal the role and implications of evolution.
B) reveal the location of a gene on a particular chromosome.
C) be useful for diagnosing and treating genetic diseases.
D) aid in understanding the underlying causes of cancer.
E) all of the above

Question 20

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

A) 4
B) 5
C) 6
D) 3
E) 2

Question 21

During gel electrophoresis the DNA is:

A) extracted from the cell nuclei.
B) visualized using x-rays.
C) cut into fragments.
D) undergoing hybridization.
E) separated by fragment size.

Question 22

Radioactive probes are used:

A) to visualize RFLPs.
B) as molecular scissors.
C) to hold DNA in helical shape.
D) as primers for DNA polymerase.
E) as restriction enzymes.

Question 23

Which of the following is in the correct sequence?

A) addition of radioactive probe → gel electrophoresis → hybridization → Southern blotting → addition of restriction enzymes → visualization of DNA fragments
B) addition of radioactive probe → Southern blotting → gel electrophoresis → hybridization → visualization of DNA fragments on x-ray film
C) extraction of DNA from cells → hybridization → Southern blotting → gel electrophoresis → visualization of DNA fragments
D) extraction of DNA from cells → gel electrophoresis → Southern blotting → hybridization → visualization of DNA fragments on x-ray film
E) Southern blotting → gel electrophoresis → addition of restriction enzymes → addition of radioactive probe → visualization of DNA fragments

Question 24

Each cycle of the DNA Thermal Cycler takes approximately:

A) two minutes.
B) four hours.
C) 30 seconds.
D) two hours.
E) fifteen seconds.

Question 25

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

A) the analysis procedure is very rigorous.
B) such study takes a long time.
C) it costs much more than nuclear DNA profiling.
D) little mtDNA is present in a cell.
E) None of the above are true.

Question 26

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

A) hydrolyze polymerase.
B) synthesize protein.
C) copy DNA.
D) make probes radioactive.
E) analyze the sequence of bases.
Use this DNA RFLP pattern of evidence from a rape investigation to answer the following question(s) .
Semen
Blood of Recovered Blood from Blood from Blood from
Victim from Victim Suspect A Suspect B Suspect C
________
________
________
________
________
________
________
________
________

Question 27

Use this DNA RFLP pattern of evidence from a rape investigation to answer the following question(s) .
$\begin{array}{c}&\text{ Semen}\\\text { Blood of } & \text { Recovered } & \text { Blood from } & \text { Blood from } & \text { Blood from } \\\text { Victim } & \text { from Victim } & \text { Suspect A } & \text { Suspect B } & \text { Suspect C }\\&&-\\-\\&-\\&&-\\&&&-\\&&&&-\\-\\&-\\&&&&-\\\end{array}$

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

A) band shifting occurred.
B) his DNA was contaminated during the collection process.
C) he is homozygous for the gene.
D) he did not provide a complete sample to the laboratory.
E) he is trisomic for the trait.

Question 28

Use this DNA RFLP pattern of evidence from a rape investigation to answer the following question(s) .
$\begin{array}{c}&\text{ Semen}\\\text { Blood of } & \text { Recovered } & \text { Blood from } & \text { Blood from } & \text { Blood from } \\\text { Victim } & \text { from Victim } & \text { Suspect A } & \text { Suspect B } & \text { Suspect C }\\&&-\\-\\&-\\&&-\\&&&-\\&&&&-\\-\\&-\\&&&&-\\\end{array}$

-The evidence suggests which suspect raped the victim?

A) The evidence suggests that two of the suspects raped the victim.
B) suspect A
C) The evidence shows that none of these suspects is a match.
D) suspect C
E) suspect B

Question 29

What 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
E) A and B only

Question 30

What laboratory procedure has made possible the development of bacteria that can synthesize insulin?

A) karyotyping
B) gene splicing
C) electrophoresis
D) PCR
E) Southern blotting

Question 31

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) three peaks.
B) two peaks.
C) six peaks.
D) four peaks.
E) eight peaks.

Question 32

The transfer of DNA fragments onto a nylon membrane is called:

A) PCR.
B) replication.
C) Southern blotting.
D) hybridization.
E) polymerization.

Question 33

The separation of STRs using capillary electrophoresis:

A) evolved from the flat-gel electrophoresis approach.
B) automates sampling and data collection.
C) decreases analysis time.
D) is currently the preferred method.
E) all of the above

Question 34

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

A) DNA to be extracted from the nucleus of the cell.
B) hybridization to take place.
C) double-stranded molecules to separate completely.
D) process to take place without DNA degradation.
E) DNA to coil very tightly in the helical shape.

Question 35

HV1 and HV2 are:

A) regions of mtDNA.
B) restriction enzymes.
C) STR types.
D) types of viruses.
E) CODIS search parameters.

Question 36

STR analysis has replaced RFLP DNA typing because it:

A) can be implemented using the PCR.
B) is less subject to sample degradation.
C) requires a smaller sample size.
D) reduces time to obtain results from a sample.
E) all of the above

Question 37

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

A) gender.
B) age.
C) blood type.
D) eye color.
E) ethnicity.

Question 38

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

A) less than
B) greater than
C) the same as

Question 39

CODIS is a national system of:

A) shared databases of DNA typing information from convicted felons and crime scene evidence.
B) vastly enhanced 911 emergency systems.
C) computers to track the movement of sex offenders released from prison.
D) standards for forensic science evaluators.
E) crime laboratory directors.

Question 40

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) greater than
B) the same as
C) less than

Question 41

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

A) after drying and rehydrating
B) after removal from surface of deposition and rehydration
C) immediately while still wet
D) after dried
E) in a druggists fold

Question 42

Compare and contrast STR with RFLP analysis.

Question 43

Describe how you would collect and preserve bloodstained evidence for latter use in DNA analysis.

Question 44

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

A) EDTA
B) CODIS
C) Rh factor
D) ethylene glycol
E) none of the above

Question 45

Luminol can be used at crime scenes to:

A) detect traces of blood without compromising potential DNA typing.
B) light up the crime scene with high degree of illumination.
C) make hair evidence fluoresce.
D) prove the presence of illicit drugs.
E) locate latent prints that otherwise would be overlooked.

Question 46

Buccal cells are obtained from:

A) semen.
B) urine.
C) blood.
D) the mouth and inside of the cheek.
E) fingers.

Question 47

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

A) deciding immigration cases based on family relationships.
B) matching a suspect to biological evidence found at a crime scene.
C) ruling out a suspect.
D) settling matters of questioned paternity/maternity.
E) determining whether an individual carries a genetic defect.

Question 48

Explain the forensic value of VNTR's.

Question 49

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

A) three
B) two
C) four
D) one
E) five

Question 50

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

A) greater than
B) the same as
C) less than

Question 51

List and briefly describe the process of PCR.

Question 52

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

A) zero
B) three
C) one
D) two
E) none of the above

Question 53

STRs normally consist of repeating sequences of:

A) 3-7 bases.
B) 18-2 bases.
C) 13-17 bases.
D) 8-12 bases.
E) 1-2 bases.

Question 54

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

A) in breathable paper after blood has dried
B) in an airtight clear plastic container
C) in an airtight metal container
D) in breathable paper while blood is still wet
E) in a metal paint can

Question 55

Using the low copy number DNA protocol, analysts are able to examine samples containing as few as ________ cells.

A) 800
B) 18
C) 180
D) 2000
E) 36

Question 56

Diagram the complementary strand for the following DNA segment ATAGCCGTA.

Question 57

Define and explain the forensics value of CODIS.