Fo Sci
DNA Questions #1
Name __________________________________
Use PPT slides 1-11 to answer the following questions.
1) Who are these gentlemen and what did they discover?
____________________________________________
_____________________________________________
What year did they make their discovery? ___________
2) DNA is composed of nucleotides. A nucleotide is a unit of a
nucleic acid. Many nucleotides make a strand of DNA and two
strands make the double helix of a DNA molecule. There are 4
different types of nucleotides. What are their names and what
letter symbols are used to identify them?
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
3) DNA is considered a double helix. That means that it is made of two strands of nucleotides that sit opposite of
each other joined by hydrogen bonds. If one side of a strand of DNA has the following code, what is the
complimentary strand sequence of nucleotides? (Your strand will look a lot like the strand below but it will have
complimentary nucleotides opposite the nucleotides listed—A-T and C-G).
A - G - C - T - T - G - A - C - T - C -C - T - G - A - T - A
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4) What type of bonds hold the two strands of DNA together? Are they strong or weak bonds?
___________________________________________________________________________________________
5) What is a gene? What do coding genes carry the code for? What is the value of non-coding genes?
___________________________________________________________________________________________
___________________________________________________________________________________________
6) Why is it important for most coding genes in humans to be identical in nucleotide sequence? For example, why
is it necessary for all humans to have the same nucleotide sequence for their hemoglobin molecules?
___________________________________________________________________________________________
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7) Fill in. There are two types of DNA found in your cells. The first type, _________________ is found in the
nucleus of your cells. It is in the form called ______________________, which are linear structures that are
made of DNA and proteins. Each of your cells has ____________(number) pieces of these linear structures in
the nucleus. The linear structures are paired. One of the pairs is inherited from your mother (maternal) and the
other is inherited from your ________________(paternal). The nucleotide sequences in your
_____________________(linear pieces) is an important type of forensic evidence even though it is
________________(individual/class) evidence. The strength of this evidence makes it as important as the
individualized evidence you worked with in the last unit: __________________.
Unfortunately, nDNA is fairly fragile and breaks down easily. The second type of DNA is smaller, and is circular in
shape. It does not break down as easily and can be obtained from very old or dried samples. This second type
of DNA is ___________________________. This DNA is found in the organelle in your cells called the
_______________________________________. You have hundreds of these organelles in one of your cells.
Therefore, you have ___________________ (a number) copies of this type of DNA in one cell. The function of
the organelle is _______________________________________________________________. The DNA in this
organelle is inherited from your ___________________. As such, the nucleotide sequence you inherit from your
mother will be identical to the sequence any of your siblings inherits. Your aunts and cousins on your mom’s
side of the family will also have the same sequence of nucleotides in their mtDNA because they all inherited the
sequence from your grandmother! This type of evidence is helpful but it is only _______________(individual/
class) evidence and it is not as valuable as a nDNA profile.
Word Bank:
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chromosomes
class
entomology
father
fingerprinting
individual
mitochondria
mother
mtDNA
n DNA/ chromosomes
nuclear DNA
one
ten
thousands
8) Are coding genes used in DNA fingerprinting? Why or why not?____________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
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Match the following types of DNA to the statements below:
a. nDNA
b.mtDNA
c. both types of DNA
9) Used to identify the source of evidence.__________
10) The best type of class evidence.___________
11) Fragile and easily broken down.________
12) Can be isolated from degraded skeletal remains._______
13) Is only inherited from the maternal side._________
14) Is identical in identical twins.__________
15) Thousands of copies are found in each cell.__________
16) Contains approximately 20,000 coding genes.__________
17) Composed of a circular piece of DNA.___________
18) Some genes code for proteins.____________
19) Contains 3 billion base pairs.___________
20) Contains alleles.__________
21) Composed of A, T, G and C nucleotides.__________
22) Represented by picture to upper right. ____________
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DNA Questions #2
Fo Sci
Name __________________________________
Use slides 11-21- to answer the following questions: (some questions may be answered using previous slides)
23) Which of the following is true about your nuclear-nDNA? ( 2 answers)
a. It is identical to your mother’s DNA.
b. It is similar to your both of your parents DNA.
c. It is part of your paired chromosomes. One of each pair is inherited from
your mother (maternal) the other is from your father (paternal).
d. It contains genes that code for carbohydrates and fats.
e. Some chromosomes are linear while the smaller ones are circular in shape.
24) A gene is located at a specific spot (or loci) on a chromosome. The allele at that loci is the nucleotide sequence
for the gene found at that location. If a gene found on the paternal #20 chromosome has the following allele
sequence: A_T_G_C_C_A_T_A, and the alleles between the maternal and paternal homologs are heterozygous,
which of the following alleles could be on the maternal #20 chromosome at the same gene loci? (circle two
possible answers)
a. A_T_C_C_C_A_T_A
b. A_T_G_C_C_A_T_T
c. A_T_G_C_C_A_T_A
25) What percent of your DNA codes for proteins (coding DNA)?
a. 97%
b. 50%
c. 25%
d. only 2-3%
26) You can find non-coding DNA
a. In between genes
c. Within genes
b. In nDNA
d. All of these
27) How is non-coding DNA different from coding DNA? Which type of DNA is best for DNA profiling? Why? (This
question is redundant—it WILL be on the test!)
___________________________________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
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28) A tool used to determine the identity of, or verify the identification of and individual based on DNA is
called a ____________________________________________. Do not confuse it with a regular fingerprint!
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29) DNA profiling uses _____________________(coding, non-coding) regions of the DNA to compare body fluids at a
crime scene to an individual.
30) What does S-T-R stand for? ___________________________________ Is it a length polymorphism? _________
___________________________________________________________________________________________
31) How do tandem repeats like STR’s differ from person to person? ______________________________________
_______________________________________________________________________________________________
32) A person has 5 tandem repeats for an STR with the sequence: TATC. Write the sequence for the allele below:
___________________________________________________________________________________________
The 5 repeats are on the paternal homolog for chromosome 15. If the person is heterozygous for the
polymorphism, what number of repeats might you find on the maternal homolog?
___________________________________________________________________________________________
Write out a possible (there are many different answers here) sequence for the maternal homolog:
___________________________________________________________________________________________
33) How many nucleotides are in a single repeat of a typical Short Tandem Repeat (STR)? _____________________
34) What does purification do to DNA? ______________________________________________________________
35) What is amplification? What is the process called that can amplify segments of the DNA? _________________
___________________________________________________________________________________________
___________________________________________________________________________________________
36) Which of the following might be a source of nDNA? ________________________________________________
a.
saliva
b. buccal cells
c. urine
e. red blood cells
g. feces
d. skin cells
f. white blood cells
h. semen
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DNA Questions #3
Fo Sci
Name __________________________________________
Use slides 20-27 to answer the following questions: (some questions may be answered using previous slides)
37) What does PCR stand for? What is the function of the PCR process? ___________________________________
___________________________________________________________________________________________
38) What process that normally takes place in a cell is most similar to PCR amplification?
_______________________________________________
39) Which of the following is a significant difference between amplification of DNA in a cell (DNA Replication) and
amplification of DNA by PCR for a DNA profile?
a. replication takes place in the cytoplasm while amplification takes place in the nucleus of the cell
b. replication copies all of the DNA in the nucleus but amplification only copies shorter, target sequences
c. replication makes thousands of copies of the nuclear DNA while PCR amplification makes only one copy of
each target sequence.
d. replication occurs in a thermocycler while PCR can take place inside of a living cell.
40) Place the following in order of how the process of PCR takes place:
a. weak hydrogen bonds between complimentary nucleotides break
b. Begin again
c. DNA polymerase helps to add nucleotides to the single strands of DNA
d. Primers attach to ends of the target sequences
e. Cool down stabilizes new strands
f. Heat up DNA
answer: _________________________
41) What is the correct order of the following processes in DNA profiling?
a. Gel electrophoresis to visualize the DNA
b. Purification of sample to eliminate all materials but cells
c. PCR to amplify the DNA to produce billions of copies
d. Extraction of DNA from the cells
answer: ___________________________________
42) Visualize means to “see” something. Do you think you could visualize a few strands of DNA?___________
How many strands of DNA are produced during PCR? ________________ (10’s, 100’s, 1000’s, billions)
Why do you have to run a PCR on the DNA before you can visualize the results in gel electrophoresis?
___________________________________________________________________________________________
43) Which of the following are true? (Correct any false statements.)
a. When PCR is used, all of the DNA is amplified. _______________________________________________
b. The product of the PCR process is several copies of the target sequence. _________________________
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