Forensic DNA Analysis Introduction to DNA The Cell

The Cell • Smallest unit of life • Compose all living things • The

Chromosomes • our body’s way of organizing all the information that our genetic material

Genes • Each chromosome contains 100 s to 1000 s of information blocks called

DNA • Each chromosome and every gene is made of deoxyribonucleic acid (DNA) •

Nucleotides Phosphate Sugar The nitrogenous base is always one of four molecules: adenine guanine

The DNA Backbone • Nucleotides are liked together with alternating P-S-P……. .

The DNA Double Helix • DNA is normally double stranded • The two nucleotide

The DNA Double Helix The two strands wrap around each other to form helical

Functions of DNA • Two primary functions - transmit information from one generation to

DNA Replication • DNA is unwound • An enzyme called DNA Polymerase adds complementary

Restriction Enzymes Enzyme that cuts DNA at specific sequences Recognize and binds to 6

Gel Electrophoresis • Gel with different sized pores agarose and acrylamide are common materials

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Forensic DNA Analysis Introduction to DNA

The Cell • Smallest unit of life • Compose all living things • The “nucleus” (one of many organelles) contains genetic information the cell needs to exist and reproduce - most cells organize genetic information into chromosomes

Chromosomes • our body’s way of organizing all the information that our genetic material contains • 23 pairs in humans - each pair contains one from mother and one from father

Genes • Each chromosome contains 100 s to 1000 s of information blocks called genes • Each gene is the blueprint for a specific protein in the body - may tell our body what color our eyes are supposed to be, dozens of proteins are responsible for synthesis of ATP, digesting food, etc etc

DNA • Each chromosome and every gene is made of deoxyribonucleic acid (DNA) • DNA is a polymer of repeating units called nucleotides • Each nucleotide contains three parts - phosphate group - sugar (deoxyribose) - nitrogenous base

Nucleotides Phosphate Sugar The nitrogenous base is always one of four molecules: adenine guanine cytosine thymine

The DNA Backbone • Nucleotides are liked together with alternating P-S-P……. .

The DNA Double Helix • DNA is normally double stranded • The two nucleotide chains are held together by hydrogen bonds • A always pairs with a T on the other strand; C always pairs with G

The DNA Double Helix The two strands wrap around each other to form helical structure shown (double helix)

Functions of DNA • Two primary functions - transmit information from one generation to the next - provide blueprint for making proteins the same way every time Two Types of DNA • nuclear or chromosomal DNA (inherited from mother and father) • mitochondrial DNA (inherited from mother only)

DNA Replication • DNA is unwound • An enzyme called DNA Polymerase adds complementary bases to “single stranded” - A with T - C with G

Restriction Enzymes Enzyme that cuts DNA at specific sequences Recognize and binds to 6 -8 nucleotide stretch

Gel Electrophoresis • Gel with different sized pores agarose and acrylamide are common materials • Load DNA samples into wells at top of gel • Run electric current through the gel • DNA moves due to negative charge • Smaller bands run “faster”