Study Guide DNA Unit

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

made up of one or more long, folded chains of amino acids (each called a polypeptide), whose sequences are determined by the DNA sequence of the protein-encoding gene.

the fundamental molecule that serves as the building block for proteins

Stands for deoxyribonucleic acid and contains genetic information, found in chromosomes located in nucleus of cells, composed of nucleotides (a single unit), contains sugar molecule (deoxyribose), phosphate group, nitrogen containing base (A,T,G,C). Double helix- two coiled DNA strands

mtDNA. Found in the cytoplasm, is inherited only from mother. Each cell contains hundreds to thousands of mitochondria, can be found in skeletal remains. Analysis of mtDNA is more: rigorous, time consuming, costly than nucleic testing of DNA

the basic building block of nucleic acids (RNA and DNA). A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T)

adenine will always pair with its complement thymine and cytosine will always pair with its complement guanine

Each DNA molecule resulting from replication has one original strand and one new strand

Any change in the DNA sequence of a cell AKA an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Mutations may be caused by mistakes during cell division, or they may be caused by exposure to DNA-damaging agents in the environment. Mutations can be harmful, beneficial, or have no effect

Variable Numbers of Tandem Repeats- a type of repeating DNA sequence, the number of repeats varies from person to person, 9 to 80 bases in length polymerase chain reaction (PCR) can be used to amplify the DNA that contains the VNTRs

STR’s which are 2-5 bases in length. Shorter lengths make STR’s easier to use than VNTR’s restriction enzymes are unnecessary; PCR allows the amplication of the strands with STR sequences

used with a high degree of accuracy, biological evidence is examined for the presence of inherited traits. Some forensics laboratory techniques were originally developed for other purposes

(Polymerase chain reaction) allows the amplification of the strands with STR sequences. a laboratory technique for rapidly producing (amplifying) millions to billions of copies of a specific segment of DNA, which can then be studied in greater detail

Bands of DNA are separated by size using electric current, DNA is mixed special enzymes, enzymes cut apart the DNA in specific places forming different sized fragments, DNA is separated within an agarose gel, an electric current is passed through the gel separating the fragments by size

bonds between bases hold the two strands together, G-C has 3, A-T has 2, can be broken easily, two strands can separate to be copied

an acronym for Combined DNA Index System, which is a computer software program that operates local, state, and national databases of DNA profiles from convicted offenders, unsolved crime scene evidence, and missing persons

(Healing) - heat briefly to separate DNA strands. Due to abrupt changes in environmental conditions like temperature, pH etc., the DNA double helix unwinds and the hydrogen bonds between the base pairs are broken. favorable to DNA hybridization

(Cooling)- cool to allow primers to bond with ends of DNA.

DNA polymerase adds nucleotides to the end of each primer

a short nucleic acid sequence that provides a starting point for DNA synthesis

enzymes that create DNA molecules by assembling nucleotides, the building blocks of DNA

identifying potential suspects, exonerating individuals (finding them not guilty/set free), identifying crime scenes and victims (burned bodies, decomposed bodies, etc), establishing paternity and proving family relations, matching organ donors, identifications of john doe or jane doe, studying evolution and ancestry (through nuclear and mitochondrial DNAs), studying inherited disorders

DNA molecule separates into two strands. Then produces two complementary strands. Each strand of the double helix of DNA serves as a template, or model, for the new strand

Extraction, Amplification, Gel Electrophoresis and Probes