Chapter 19/20

Viruses/Biotechnology

Lytic Cycle: Virulent• Virus replicates

genetic material• Host cell creates

new viruses• Host cell breaks &

spreads viruses• Bacteria contain

restriction enzymes for protection

• Examples: Flu, cold, chicken pox, polio, smallpox, EBV-mononucleosis

Lysogenic Cycle: Temperate• Creates prophage• Viral DNA gets

copied and passed on with cell DNA

• Env. Trigger starts lytic cycle

• Viral DNA can create toxins

• Ex: HIV, HPV, Herpes, EBV-lymphoma

Retrovirus• Genetic material enters

cell• Reverse transcriptase

creates RNA-DNA hybrid, then copies DNA

• Inserts DNA into cell DNA• Makes RNA & proteins• Creates new viruses

which spread & DNA gets copied and passed on to other cells

Viroids/Prions• Viroids – circular RNA

molecules, only infect plants

• Prions-infectious proteins– Little known– Misfolding proteins– NO treatment

DNA Cloning

DNA Cloning

• Place gene of interest into plasmid1.Cells with gene replicate and produce more

genes2.Multiple copies allows research and

application3.Genes make proteins & proteins can be

isolated and used

Restriction Enzymes

• Cut up foreign DNA• Used to make recombinant DNA• DNA ligase

PCR

• DNA heated up• Primers form, DNA pol.

Creates new DNA• Only requires small

amounts of DNA• Used a lot in forensics &

genetic diagnosis

Gel Electrophoresis• Restriction enzymes

break DNA into segments

• Diff. sizes & charges go diff. distances

• Can isolate individuals genes & show DNA makeup

• Review your lab (you will get back Monday

RFLP (Restriction Fragment Length Polymorphism)

• SNPs (single nucleotide polymorphism) are changes single base pair variations

• Change the DNA segment recognized by restriction enzymes

• Creates new segments called RFLP• Act as genetic markers