Human Biology Chapter 8 - Technology used to treat diseases

biotechnology

Location of DNA

-found in cell of all organisms

-usually in nucleus, some in mitochondria and some in cytosol

Structure of DNA

-consist of two strands of nucleotides

-double helix due to twisted into spiral

-bases paired with complementary base pairing:

Adenine = Thymine, Guanine = Cytosine

Nucleotide

deoxyribose sugar molecule, phosphate group and nitrogenous base

Tissue engineering

-requires abundant supply of disease free cells of specific types

Artificial breeding

↑ or ↓ incidence of certain genes

-slow and inefficient process (gene passed on by chance & wast for next generation to mature before knowing outcome)

-e.g. selecting which female and male organisms breed

Genetic engineering

involves artificial modification of DNA(recombinant DNA tech)

-DNA either added or removed from cell

-DNA produced = recombinant DNA

-organism = genetically modified organism (GMO)

Uses of genetic engineering

-introduce genes for desired traits into organism

-involve DNA from one species introduced to a different species (transgenic organism) = introduce trait not normally present

Steps/basis of genetic engineering

-gene for desired trait must be identified & isolated

-DNA receiving gene must be ‘opened’

-gene added to recipient & join its DNA

Restriction enzymes

-known as endonuclease

-certain enzymes that cut up viral DNA

-can be bacteriophages or phages

-cuts DNA at recognition site (sequence)

-cuts DNA to restrict duplication of bacteriophages

Recognition site

-point of DNA where there is a certain sequence of bases is cut

-about 4-8 base pairs in length

palindromic

-same sequence when read forward and backwards

-same sequence occurs on both strands within recognition site

Types of cuts produced by restriction enzyme

-Straight cut - clean break across two strands of DNA producing blunt end (both strands terminate in base pair)

-Staggered cut - fragments with sticky ends (stretch of unpaired nucleotides in DNA molecules - overhang at break in strands)

DNA Ligase

-glue together short strands of DNA during replication (ligation)

-join phosphate group at end of one strand to sugar molecule at end of another strand

Vector

DNA molecule - carry DNA into cell

-commonly used: bacterial plasmids & bacteriophage viruses

-used for production of organisms with recombinant DNA

Plasmids

Circular, double stranded units of cytoplasmic DNA

-found in bacteria

-capable of replicating within the cell independently

Recombinant DNA

gene of interest integrated into plasmid or bacteriophage virus