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:

**A**denine = **T**hymine, **G**uanine = **C**ytosine

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

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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)

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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