Protein Synthesis ("making proteins")
I.
Review: Proteins
A.
1 of 4 biomolecules (macromolecules, organic molecules)
B.
polymer = protein, polypeptide, peptide chain, enzyme, amino acid
chain
C.
monomer = amino acid
D.
(enzymes) typically ends in --ase
E.
structural proteins and enzymes are vital for cell survival; all cellular
functions depend on proteins; w/out protein --> cell dies --> you die!
II.
DNA v. RNA
DNA
RNA
name
components
name of sugar
N2 bases and
complimentary
base pairs
shape of molecule
processes
involved in
forms/functions
location(s) in cell
III.
How it is read
A.
DNA nucleotide bases are read in a group of 3 called a DNA triplet
B.
mRNA (messenger RNA) is read in a group of three called a codon
-- an mRNA sequence always starts with a "start codon" (AUG methionine) and ends w/ 1 of 3 "stop codons" (UAA, UAG, UGA)
C.
tRNA (transfer RNA) is read in a group of three called an anticodon
D.
codons are translated into amino acids using a "codon chart"
E.
codon charts are for mRNA codons ONLY!!! DNA triplets and tRNA
anticodons MUST be translated to mRNA codons first!
IV.
"Building proteins"
A.
Transcription
1.
mRNA enters the nucleus through a nuclear pore and makes a
copy of DNA (transcription)by base pairing with exposed DNA
bases on the template (5') strand: **DNA adenine base pairs
with mRNA Uracil; no thymine in RNA!
2.
RNA polymerase binds to DNA to start mRNA transcription
3.
analogy: bike messenger slips into the Nucleus Architecture
Firm building to make a copy of a particular blueprint for the
new Protein housing project
B.
Translation
1.
mRNA leaves the nucleus and enters cytoplasm and connects
to ribosome where it is translated into anticodons by tRNA;
2.
tRNA brings the amino acid specified by each codon to the
ribosome
3.
analogy: the messenger (mRNA) brings the copy of the
blueprints it has written to tRNA. tRNA's job is to go get all the
building materials. When tRNA reads the "list", he realizes it is
written backwards; tRNA then interprets what the code should
say, gathers the appropriate building materials (amino acids)
and delivers them to the building site (the ribosome)
C.
Protein Synthesis
1.
After the specific amino acid is delivered by tRNA to the
ribosome, rRNA assembles the amino acids in the correct
sequence to build the specified protein
2.
analogy: rRNA assembles the bricks (amino acids)in order to
build the house (protein) according to the blueprints(segment
of DNA) copied by mRNA