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STUDY GUIDE
Chapter 11 DNA Analysis
Be a super sleuth…discovering and answering the following questions will prepare you
for acing your first exam.
Define allele:
Define amino acid:
Define chromosome:
Define DNA:
Define electrophoresis:
Define enzyme:
Define gene:
Define Human Genome Project:
Define polymerase chain reaction:
Define probe:
Define proteins:
Define restriction enzyme:
Define short tandem repeats:
What is the common way of identifying people using their unique genetic code?
What are three (3) ways in which DNA is currently being used?
Where is DNA found in the human body?
List six (6) locations found in or on the human body from which DNA can be
extracted:
What are the four (4) base pairs of DNA?
In what way are these four (4) bases always paired in DNA and with what type
and how many bonds?
Why are these bases referred to as “nitrogenous bases”?
What are the three (3) components of a nucleotide unit?
What sugar is always found in DNA?
Compare the DNA Double Helix to a ladder:
If all of the DNA in the human body was put end to end, what celestial body
would be reached and how many times would it be reached?
What are fraternal twins and what percent of their DNA do they share?
What are identical twins and what percent of their DNA do they share?
Describe in detail the first use of DNA identification:
Who coined the term “DNA fingerprints”?
Describe in detail the first forensic use of DNA technology?
What makes humans unique and what is the exception to the rule?
What are the two (2) most common forms of evidence that forensic scientists use
for testing DNA?
What are the four (4) components of blood and tell the function of each
component?
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Which of the blood’s four components is of interest to forensic investigators and
why?
What are the five (5) uses that your book gives for DNA profiling?
What are the steps taken to prepare DNA for analysis?
Describe in detail the case of Snowball:
What does RFLP DNA analysis stand for?
What is used to cut DNA into smaller pieces for testing?
What is the process used to separate DNA fragments according to their size?
What are the four (4) main procedures involved in DNA fingerprinting?
What DNA fact is used by electrophoresis to separate the fragments?
Which fragments travel more easily through the gel during electrophoresis?
What are the three (3) steps in PCR?
What are the advantages of PCR?
Give three (3) reasons why is the STR method becoming more common the RFLP
method:
Where and when did the Innocence Project begin?
What is the purpose of the Innocence Project?
Describe in detail the case of Eddie Joe Lloyd:
What is CODIS?
Mitochondrial DNA is inherited from whom?
What are two (2) disadvantages of mitochondrial DNA testing?
Who was Gary Ridgeway and describe his case in detail?
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STUDY GUIDE
Chapter 11 DNA Analysis
Be a super sleuth…discovering and answering the following questions will prepare you
for acing your first exam.
Define allele:
o A site where two (2) genes that influence a particular trait are found on a
chromosome pair page 257
Define amino acid:
o An organic compound containing an amino group, NH2, and a carboxylic
acid page 246
Define chromosome:
o A long, threadlike group of genes found in the nucleus of a cell page 244
Define DNA:
o Deoxyribonucleic acid, the hereditary material of most organisms page
244
Define electrophoresis:
o A procedure that separates DNA fragments according to size page 249
Define enzyme:
o A protein that causes a chemical reaction to occur at a rate that is
sufficient to support life page 246
Define gene:
o A specific sequence of nucleotides in the DNA usually found on a
chromosome’ the functional unit of inheritance threaded around its
twenty-three (23) paired chromosomes page 244
Define Human Genome Project:
o A unified effort to identify and determine the sequence of all genes found
on the human chromosome page 244
Define polymerase chain reaction:
o A lab technique used to make multiple copies of DNA for further testing
or characterization page 256
Define probe:
o A portion of a DNA molecule with a known sequence of bases that is used
to find its complementary strand page 249
Define proteins
o Fundamental components of all living cells, including enzymes,
hormones, and antibodies; composed of amino acids linked together with
peptide bonds page 244
Define restriction enzyme:
o Enzymes that are used to cut DNA into smaller fragments page 248
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Define short tandem repeats:
o Specific sequences of DNA fragments that are repeated at a particular site
on a chromosome page 260
What is the common way of identifying people using their unique genetic code?
o DNA “fingerprinting” Page 244
What are three (3) ways in which DNA is currently being used?
o A. to identify the perpetrator in a crime
B. to identify fathers in paternity cases
C. too identify unknown remains in mass disasters and other situations
page 244
Where is DNA found in the human body?
o In every nucleated cell of the human body page 244
List six (6) locations found in or on the human body from which DNA can be
extracted:
o A. blood
B. semen
C. urine
D. bone
E. hair follicles
F. saliva page 244
What are the four (4) base pairs of DNA?
o (A) Adenine
(T) Thymine
(C) Cytosine
(G) Guanine page 245
In what way are these four (4) bases always paired in DNA and with what type
and how many bonds?
o (A) Adenine =(T) Thymine
with 2 hydrogen bonds
(C) Cytosine =(G) Guanine
with 3 hydrogen bonds page 245
Why are these bases referred to as “nitrogenous bases”?
o Because each of these bases contain the element “nitrogen” page 245
What are the three (3) components of a nucleotide unit?
o 1. A paired base either A=T or C=G
2. Deoxyribose sugar
3. Phosphate
page 245
What sugar is always found in DNA?
o Deoxyribose
page 245
Compare the DNA Double Helix to a ladder:
o The side of the ladder or double helix are the sugar and phosphate groups
and the rungs of the ladder are the nitrogenous bases page 245
If all of the DNA in the human body was put end to end, what celestial body
would be reached and how many times would it be reached?
o It would reach the sun and back more than 600 times page 245
What are fraternal twins and what percent of their DNA do they share?
o Result when two separate sperms fertilize two separate eggs. These twins
share only 50% of their DNA, just like regular siblings and can be same
gender or a boy and a girl page 245
What are identical twins and what percent of their DNA do they share?
o Come from one fertilized egg that splits in two, resulting in same sex
twins who share 100% of their DNA page 245
Describe in detail the first use of DNA identification:
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o Used in a non-criminal setting to prove familial relationship. A Ghanaian
boy was refused entry into the United Kingdom for lack of proof that he
the son of a woman living there. Immigration authorities claimed that the
boy could be the woman’s nephew. DNA testing showed a high
probability of a mother-son relationship and authorities admitted the boy
page 245
Who coined the term “DNA fingerprints”?
o Dr. Alec J. Jeffreys page 246
Describe in detail the first forensic use of DNA technology?
o In a criminal case in 1986, police asked Dr. Alec J. Jeffreys to verify a
suspect’s confession to two rapes in the English Midlands. Test proved
that he was innocent. Police than collected blood samples from several
thousand males in the area and were able to identify and convict the
perpetrator page 246
What makes humans unique and what is the exception to the rule?
o 99.9% of human DNA base order is the same, but 0.1% makes humans
one of a kind. The exception is identical twins who have 100% of the
same DNA page 246
What are the two (2) most common forms of evidence that forensic scientists use
for testing DNA?
o Blood and body fluids page 246
What are the four (4) components of blood and tell the function of each
component?
o 1. Red blood cells that carry the oxygen throughout the body
2. Plasma, a fluid that carries the cells
3. Platelets which facilitate clotting
4. White blood cells which defend the body against infection page 246
Which of the blood’s four components is of interest to forensic investigators and
why?
o White blood cells because they contain nucleated DNA page 246
What are the five (5) uses that your book gives for DNA profiling?
o 1. to identify potential suspects whose DNA may match evidence left at
crime scenes
2. to clear persons wrongly accused of crimes
3. to identify crime and catastrophic victims
4. to establish paternity and other family relationships
5. to match organ donors with recipients in transplant programs page 246
What are the steps taken to prepare DNA for analysis?
o 1. the DNA is removed from the object that it is attached to ssuch as
clothing weapons or skin
2. DNA is then extracted from the cell
3. DNA is then isolated from the cellular components such as lipids,
proteins, and carbohydrates
4. The final step is the use of enzymes to release the DNA from the
chromosomal packaging so that it is finally ready for characterization
page 246
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Describe in detail the case of Snowball:
o 1994, a mother of five was found murdered on Prince Edward Island. The
only evidence found was a blood-soaked jacket and a few white hairs.
The white hairs were found to belong to a cat named Snowball that
belonged to the woman’s estranged husband. Because of the near perfect
match of the white hairs’ DNA to that of Snowball the estranged husband
was sentenced to 18 years for second degree murder. Page 247
What does RFLP DNA analysis stand for?
o R – restriction enzymes are used to cut the DNA into
F – fragment(s) that are many different
L – lengths and
P – polymorphism, which is a Greek term meaning many shapes. The
length of the fragments will vary greatly among individuals Page248
What is used to cut DNA into smaller pieces for testing?
o Restriction enzymes page 248
What is the process used to separate DNA fragments according to their size?
o Electrophoresis page 249
What are the four (4) main procedures involved in DNA fingerprinting?
o 1. isolation of the DNA to separate the DNA from the cells
2. cutting with a restriction enzyme to make shorter base strands
3. sorting the segments by size, using an electrophoresis procedure
4. analyzing the resulting print y identifying specific alleles page 249
What DNA fact is used by electrophoresis to separate the fragments?
o DNA is polar or electrically charged page 252
Which fragments travel more easily through the gel during electrophoresis?
o Smaller fragments page 252
What are the three (3) steps in PCR?
o 1. separation
2. adding primer
3. synthesis of the new chain page 257
What are the advantages of PCR?
o PCR takes a very small sample and makes millions of copies by a
relatively simple, quick method page 254
Give three (3) reasons why is the STR method becoming more common the RFLP
method:
o 1. takes less time for analysis
2. takes less of a sample size
3. is more exclusionary, meaning that it can eliminate more people as
possible sources page 260
Where and when did the Innocence Project begin?
o At Cardoza School of Law in 1992 page 260
What is the purpose of the Innocence Project?
o To exonerate the wrongfully convicted through post-conviction DNA
testing and to develop and implement reforms to prevent wrongful
convictions page 260
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Describe in detail the case of Eddie Joe Lloyd:
o Convicted in 1985 for the brutal rape and murder of a 16 yr-old girl, he
was released in 2002, after wrongfully serving over 17 years based on
DNA testing post conviction. His was the 110th case of exoneration in the
U.S. based primarily on DNA evidence. page 260
What is CODIS?
o The FBI’s Combined DNA Index System lets federal, state, and local
crime labs exchange and compare DNA profiles electronically, thereby
linking crimes to each other and to previously eonvicted offenders. page
260
Mitochondrial DNA is inherited from whom?
o The mother only page 262
What are two (2) disadvantages of mitochondrial DNA testing?
o 1. more costly
2. takes considerably more time Page 262
Who was Gary Ridgeway and describe his case in detail?
o Known as the Green River Killer, he admitted to killing over 48 women in
the Seattle, Washington area over a 21 year period Page 263
o
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