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DNA and RNA. Nucleic Acids. Nucleic acids are made from nucleotide monomers A nucleotide has 3 groups Phosphate Ribose sugar Nitrogenous base. The phosphate and the ribose combine to form a long chain polymer with the nitrogenous base sticking out to the side. Fig. 15-21, p. 321.
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Nucleic Acids • Nucleic acids are made from nucleotide monomers • A nucleotide has 3 groups • Phosphate • Ribose sugar • Nitrogenous base
The phosphate and the ribose combine to form a long chain polymer with the nitrogenous base sticking out to the side
There are two types of nucleic acids • DNA – Deoxyribonucleic acid • RNA – Ribonucleic acid
There are 5 nitrogenous bases • Adenine (A) • Guanine (G) • Cytosine (C) • Thymine (T) • Uracil (U)
DNA and RNA each only use 4 of the 5 bases • DNA uses A, G, T, C • RNA uses A, G, U, C
DNA contains the whole genetic code for life within each single cell • RNA codes for a single type of protein • Thus RNA is made from DNA
In the late 1850s a monk named Gregor Mendel observed certain traits in plants • He noticed plants could pass along information such as flower color from one generation to the next
In the early 1900s chromosomes were found in cells • Chromosomes are structured DNA and only visible when cells are preparing to divide
1953 Watson and Crick determined the base pairing of DNA • A:T • G:C
Base pairing led to the discovery of the structure of DNA being a double helix
DNA replication • When cells divide the DNA must be replicated so the new cell will also have a copy
DNA to protein • DNA contains the code for each protein we need to make • This code is called a “gene” • Each gene codes for a single polypeptide • For humans we have about 40,000 genes • This makes up 20% of our total DNA
Genetic engineering • Restriction enzymes – cut DNA into smaller fragments • These are naturally occuring enzymes found in bacteria and viruses to protect their DNA from foreign DNA
These enzymes cut DNA at specific sites where there is an inverted repeat of DNA bases • CAGCGAATTCTGCACTG • GTCGCTTAAGACGTGAC
Every time this sequence occurs in DNA the enzyme will make a cut. • We can use this to our advantage
DNA fingerprints • When restriction enzymes are added to a sample of human DNA it cuts the DNA into smaller pieces • DNA has an overall (-) charge
A special technique can be used to separate DNA by its charge and size • This is called Gel Electrophoresis
By using several different restriction enzymes, each person’s DNA will be cut up into different sized fragments. • This makes up our DNA fingerprint since each person will create a unique set of bands on the gel.
Recombinant DNA • Restriction enzymes can also be used to make new strands of DNA
This allows us to make bacteria work for us as little protein production factories • Many of the proteins we need to sustain life can be produced by bacteria cheaper than we can synthesize them in a lab
Diabetics • Diabetes is a well know problem for many Americans • This disease revolves around the body’s inability to produce insulin • Insulin is a very necessary enzyme that helps get glucose into cells so they can make energy • Without insulin we would die
Until the early 80’s diabetics had to use pig insulin • Humulin was produced from bacteria carrying the human insulin gene and marketed in 1983 • Less compatibility problems using Humulin than pig insulin
Many other human products are now begin produced by bacteria instead of being harvested from animals • Human Growth Hormone • Bovine Growth Hormone • Epidermal Growth Hormone