Chromosome
A threadlike structure in the cell nucleus composed of DNA, along which the genes are located.
Deoxyribonucleic Acid (DNA)
The molecules that carry the body's genetic info.
humane genome
The order of bases on all 23 pairs of human chromosomes.
polymer
A substance composed of a large number of atoms. These atoms are usually arranged in repeating units, or monomers.
nucleotide
A repeating unit of DNA consisting of 1-4 bases (adenine, guanine, cytosine, or thymine) attached to a phosphate (sugar group)
complementing base pairing
the specific paring of base A with T and base C with G in double-stranded DNA.
proteins
Polymers of amino acids that play basic roles in the structure and function of living things.
amino acids
The building blocks of proteins.
replication
The synthesis of new DNA from existing DNA.
polymerase chain reaction (PCR)
A technique for replicating or copying a portion of a DNA strand outside a living cell.
tandem repeat
region of chromosomes that contains multiple copies of a core DNA sequence arranged in a repeating fashion
restriction enzymes
Chemical that acts as scissors to cut DNA molecules at specific locations.
restriction fragment length polymorphism (RFLPs)
Different fragment lengths of base pairs that result from cutting a DNA molecule with restriction enzymes.
electrophoresis
a technique for separating molecules through their migration on a support medium under the influence of an electrical potential
hybridization
the process of joining two complementary strands of DNA to form a double stranded molecule
primer
a short strand of DNA used to target a region of DNA for replication by PCR
short tandem repeat (STR)
a region of a DNA molecule that contains short segments of three to seven repeating base pairs
multiplexing
a technique that simultaneously detects more than one DNA marker in a single analysis
amelogenin gene
a genetic locus useful for deterring gender
Y-STR's
short tandem repeats located on the human Y chromosome
mitochondria
small structure outside the nucleus that supply energy to the cell
sequencing
a procedure used to determine the order of the base pairs that constitute DNA
picogram
one- trillionth of a gram, or 0.000000000001 gram
low copy number
fewer than eighteen DNA bearing cells
epithelial cells
the outer layer of skin cells
substrate control
an unstained object adjacent to an area on which biological material has been disposited
buccal cells
cells from the inner cheek lining
what is DNA and why is it important to forensic scientists?
DNA is the molecules that carry the body's genetic information. It is important to forensic scientist bc it is as individual as a fingerprint and can be linked biologically to hair and semen of a person.
what are genes and what is their function? of what are genes composed and where are they located?
genes are the basic unit of heredity consisting of a DNA segment located on a chromosome. Genes make proteins
with what discovery are james watson and francis crick credited?
james watson and francis crick are credited to the discovery of the structure of DNA.
Dna is a large molecule created by linking a series of repeating units. what is this type of molecule called? what are the repeating units known as?
*This molecule is called a polymer and the repeating units are known as nucleotides
Describe the basic structure of the DNA molecule. What is the name given to this type of structure?
the basic structure of the DNA molecule is two strands of DNA connected together by nucleotides . this type of structure is known as a double helix
Name the four bases associated with DNA. How are these bases paired on the DNA molecules?
the four bases associated with DNA are adenine (A) thymine (T) Guanine (G) Cytosine (C) adenine is paired with thymine and guanine is paired with cytosine.
What aspects of DNA define the role and function of a DNA molecule?
Amino acids
DNA controls inheritable traits by producing complex molecules called:
proteins
how are proteins made? what determines the shape and function of a protein molecule?
proteins are made by linking amino acids and the sequence of amino acids determines its shape and function.
what is a human genome? name two medical applications of information about the human genome.
the human genome is the order of the base on all 23 pairs of chromosomes. This order can be used to diagnose cancer and its causes and is also used to help find cures for cancer.
briefly describe the process of DNA replication
-unwinding of the DNA strands in the double helix
-each strand is then exposed to a collection of free nucleotides
-the double strand is recreated as the nucleotides assemble in the proper order
what is PCR? Why is it useful to forensic scientists?
PCR (A technique for replicating or copying a portion of a DNA strand outside a living cell.) is the outgrowth of knowledge gained from an understanding of how DNA strands naturally replicate within a cell. PCR is useful to scientists bc it offers a disti
what is recombinant DNA? How is recombinant DNA technology used to treat diabetes?
are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in biological organisms. Recombinant DNA is
What are tandem repeats? How are they useful to forensic scientists?
Regions of a chromosome that contain multiple copies of a core DNA sequence arranged in a repeating fashion. Provide a way to distinguish one individual from another through DNA typing. ( hundreds found in human genes)
what was the dominant DNA typing procedure in the untied states until the mid 1990's?
restriction fragment length polymorphisms (RFLP)
what is a short tandem repeat (STR)? why are STRs so attractive to forensic scientists?
STRs are locations on the chromosome that contain a short sequence core that repeats itself within the DNA molecule. It is the most successful and widely used DNA profiling procedure.
name two processes by which a forensic scientist can separate (STRs) for characterization.
electrophoresis and capillary electrophoresis
list two differences btwn nuclear DNA and mitochondrial DNA
Nuclear DNA is found only in the nucleus, while Mitochandrial DNA is found outside. N-DNA : arranged in a continuous strand of bases, and contributed by both parents. M-DNA : arranged in a circular loop of bases, and contributed only by mother
name one advantage and three disadvantages of mtDNA analysis compared to nuclear DNA profiling.
advantage- more abundant and more sensitive
disadvantage- time consuming, costly, and less discriminating. also, individuals of the same maternal lineage are indistinguishable by mtDNA analysis.
what is CODIS? how is it useful to forensic scientists?
*It is a computerized program from FBI. It is the system of tracking DNA (usually sex offenders)
approximately how many DNA- bearing cells are needed to obtain an STR profile/ what term is used to describe the quantity of DNA that is below this normal level of detection?
18 low copy number ( don't need to know this one)
what type of gloves should an evidence collector wear when handling biological evidence? name two reasons he or she should wear this type of glove.
latex gloves because all body fluids should be assumed infectious and we want to prevent contamination
what type of packaging should not be used for biological evidence? why? why type of packaging should be used instead for articles containing biological evidence?
want to avoid plastic, air tight containers to avoid mold growth and contamination should use paper bags or card board boxes
how should packages containing biological evidence be stored until they are delivered to a laboratory?
refrigerated or in some kind of cool location where it is avoiding the sun light
what substance should be added to blood samples collected from a crime scene? name two reasons for adding this substance to blood evidence.
preservative EDTA preserves enzymes to prevent DNA from breaking down and also prevents mold growth
name and describe the least intrusive method for obtaining a DNA standard/reference.
buccal swab which is a swab of the cheek cells
list four ways to minimize contamination of biological evidence.
change gloves before handling new evidence, collect substate control for comparisons, pick up small items of evidence with clean forceps, and package each piece of evidence in a well ventilated container
examples of polymers that contain repeating units known as nucleotides are:
DNA
how many different bases are associated with the makeup of DNA?
4
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
TACG
the production of amino acids is coded by a sequence of how may bases on the DNA molecule?
*
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
e. can determine if a person has sickle-cell anemia
c. are repeated many times
which of the following is false?
a. RFLP and STR segments are both tandem repeats
b. RFLP strands are more likely to decompose as compared to STRs.
c. RFLP strands are to long to be amplifies by PCR
d. RFLP DNA strands are much shorter in length than STRs
d. RFLP DNA strands are much shorter in length than STRs (false)
the concept of simultaneously extracting, amplifying, and detecting a combination of STRs is known as:
Multiplexing
the fundamental hit of heredity is the ___.
gene
each gene is actually composed of ___, specifically designed to carry out a single body function.
DNA
a(n) ____ is a very large molecule made by linking a series of repeating units
polymer
a(n) ____ is composed of a sugar molecule, a phosphate-containing group, and a nitrogen containing molecule called a base.
nucleotide
DNA is actually a very large molecule made by linking a series of ____ to form a natural polymer.
monomers
___ different bases are associated with the makeup of DNA
nucleotides
watson and crick demonstrated that DNA is composed of two strands coiled into the shape of a(n)____.
double helix
the structure of DNA requires the pairing of base A to ___ and base G to ___.
T; C
The base sequence T-G-C-A can be paired with the base sequence____ in a double helix configuration
A-C-G-T
the inheritable traits that are controlled by DNA arise out of DNA's ability to direct the production of ____.
proteins
___ are derived from the combination of up to twenty known amino acids
proteins
the production of an amino acid is controlled by a sequence of ___ bases on the DNA molecule
3
true or false: enzymes known as DNA polymerase assemble new DNA strands into proper base sequence during replication
true
true or false: DNA can be copies outside a living cell
true
recombinant DNA relies on the ability of chemicals known as ___ to cut DNA into fragments.
restriction enzymes
in RFLP DNA typing restriction enzymes are used to cut out___ sequences from the DNA molecule.
repeating
in RFLP DNA typing restriction enzymes are used to cut out sequences of DNA with different ___.
lengths
DNA fragments can be sorted according to their size by the technique of____.
electrophoresis
In the RFLP DNA typing process, DNA fragments are transferred to a nylon membrane by a process called ____ blotting
*southern
true or false: specimen amenable to DNA typing are blood, semen, body tissue, and hair.
true
short DNA segments containing repeating sequences of three to seven bases are called ____.
STRs
true or false: the longer the DNA strand, the less susceptible it is to degradation.
false
the short length of STRs allows them to replicated by ____.
PCR
the concept of ____ involves simultaneous detection of more than one DNA marker.
multiplexing
DNA fragments can be separated and identified by ____.
capillary electrophoresis
mitochondrial DNA is inherited from the ____.
mother
true or false: mitochondrial DNA is kore plentiful in the human cell than is nuclear DNA.
true
the national DNA database in the untied states has standardized on ____ STRs for the entry into the database.
13
small amounts of blood are best submitted to a crime laboratory in a ____ condition.
dry
true or false: airtight packages make the best containers for blood-containing evidence.
false
A goes to what in mRNA?
A -> U
A goes to what in DNA?
A -> T