Chp 8 - Technology to treat Diseases Human Bio

Define Biotechnology

• use of biological (cellular) processes to produce useful products

What is the Structure of DNA (Long summar)

DNA : Deoxyribonucleic acid

→ found on cells of all organisms (nucleus humans)

• 2 strands of nucleotides (deoxyribose sugar molecule, phosphate group, nitrogenous base)

• → nucleotides join tgt

• Bases from 2 strands attracted to one another by hydrogen bonds (forms cross-links between two strands)

• DNA molecule twisted into double helix.

• Adenine + Thymine, Cytosine + Guanine

• Order in which nitrogen bases occur in DNA molecule = genetic info that determines structure of cell & way it functions

What is artificial selection or selective breeding?

Genetic engineering where humans select desired traits & choose parents based on these traits

→ slow & inefficient process

What is recombinant DNA technology?

• type of genetic engineering which involves artificial modification of DNA by adding or removing DNA from a cell

• → DNA produced = Recombinant DNA

• → organism = genetically modified organism (GMO)

What is a transgenic organism?

• organism where DNA from one species is introduced into a different species

• → aim: introduce trait that is not normally present

What are the requirements for genetic engineering/ modification of DNA

1. Must be able to extract & purify DNA

2. Must be able to cut DNA exactly where you want

3. Must be able to make enough copies of DNA to work w (amplify DNA)

4. Must be able to insert a piece of DNA exactly where you want into another piece of DNA (recombination)

5. Mist be able to identify successful recombination events

6. Must be able to read sequence of DNA

What is the enzyme that is needed for modification of DNA?

Restriction enzymes: cut DNA at specific places/sites

→ restricts duplication of bacteriophages

→ cut at specific sequence of bases : Recognition site

What are restriction endonuclease/enzymes?

• occurs naturally in bacterial cells

• Natural function: protect bacterium from foreign DNA (bacteriophage)

• Many different types

• Always palindromic sequence

• Cleans DNA at phosphate-sugar bond

What types of cuts do restriction enzymes make?

1. Straight cut

2. Staggered cut

What are straight cuts?

• when restriction enzymes makes clean break across two strands of DNA to produce a blunt end

What are blunt ends?

• when both strains terminate in a base pair

What is a staggered cut?

• results in fragments w sticky ends

What are sticky ends?

• stretch of unpaired nucleotides in DNA molecule that overhang at the break in strands

What is the structure of recognition sites?

4-8 base pairs in length

→ palindromic (same sequence back & forwards)

→ same sequence occurs on both strands within recognition sites (bcs base nature is complementary)

= both strands cut, result in DNA molecule forming two segments

Why are sticky ends useful in recombinant DNA?

→ allow single stranded overhang from one DNA fragment to be paired w any