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DNA BASICS
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DNA and RNA - there are lots (we discussed at least 4 differences)
DNA has one more OH (deoxy vs ribose)
1 vs 2 strand, one type of DNA but at least 3 types RNA
DNA is only in the nucleus but RNA is in cytoplasm
DNA is complete instructions (with Introns)

• 3 basic types RNA
ü mRNA, tRNA, rRNA - messenger, transfer, ribosomal
• Codons
ü groups of three nucleotides, each is an amino acid - each amino acid = protein
ü important beginning, code for start and stop
• transcription factors and RNA polymerase controlling rate of transcription
ü 5+ types - operator (on/off switch) activator (stimulator), GTFs (bind to promoters) enhancer, promoter
(locate), both increase activity and repressor, silencer, inducer, mediators are helpers, reversible different parts of a committee
ü histone tails are accessible - cause reactions
• structure of tRNA and the Wobble Hypothesis
ü the tRNA has three fold clover structure operates like a key - bottom-most leaf is the anti-codon and the
portion at the top can shuffle it's base pairs so that it can accept other ie wobble
ü cAMP or CAP - proliferates when glucose is scarce (ex 2nd mess that can penetrate the membrane)
• different cell same genome - SHORT ANSWER - GENE EXPRESSION
ü all cells have the same stuff they just are different in the way they express - ANALOGIES INCLUDE:
different ways to play the piano, dialects, cooks + recipes
• 6 stages expression
ü TRANSCRIPTION, splicing, exporting, breakdown of proteins, protein quality control, protein switches
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6 hallmarks of cancer
self-sufficient growth
evading apoptosis
invasive to surrounding tissue and metastasis
ignore signals, rapid proliferation
sustainable angiogenesis

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Carcinoma in situ - In situ: In place or cancer that has not spread to nearby tissue, also called
non-invasive cancer

ü cell to hyperplasia to mild dysplasia to IN SITU to invasion
• Terminology
ü Stroma (blood vessels) Parenchyme (special cells of each organ) Mesenchyme (embryonic origin of
neural crest) Carcinoma (malignant epithelial) Sarcoma (malignant of mesenchyme)
• STEM cells
ü capable of dividing and renewing themselves over long periods

ü they are unspecialized and they can give rise to specialized cell types
• Cell Signals
ü Hormones (always involuntary) are slow cell signals of chemicals through the blood
ü Neurotransmitters are chemical messengers that travel fast by neurons and usually have shorter lasting
effects
• Signal transduction, and why it is so important
ü passing of communication one cell to the next - glucagon hormone provokes creation of cAMP which is
a transcription activator in the cell
• signal amplification
ü good example is cAMP 2nd message is able to carry messages into the membrane in the case of low
glucose vs primary message - branching messages



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