Transcript Exit Condition

Homework comments
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Exit Condition - 20% of quiz
1.) Pair up (two in a group)
2.) Write your names and SECTION at the top of
the paper
3.) EXPLAIN the process of TRANSLATION
Include the following in your answer:
tRNA
mRNA
ribosome
UAG codon
RNA Polymerase
aminoacyl tRNA synthetase
termination factor
diffusion
How?
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Why?
Transcription:
Writing again
Translation:
Changing
languages
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Today
we’ll go
from
here...
We can do
anything
Text
To here
Off to see the wizard...
Sending ‘messages’ out from DNA
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DNA replication
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both strands => new DNA
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=> new cell
Transcription
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1 strand => new RNA
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=> new protein
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Transcription: seeing it
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http://www.hhmi.org/biointeractive/media/DNAi_transcription_vo1-lg.mov
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Amino acids
From 4 letters of storage/information
to
20 letters of action!!
20 toys
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EVERY one has a blue part. Chem name?
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EVERY one has a red part. Chem name?
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Thus these are all...?
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How many are there?
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aaDancer
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Why do nucleotides look like nucleotides, while amino
acids look like amino acids?
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Remember the handshakes
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What are amino acids ‘for’?
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Different
tools;
different
jobs
• You & partner have an amino acid; which is it? (StructViewer or
homepage => left column ‘big twenty’ amino acids)
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In what ways are all bases identical? Different?
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In what ways are all amino acids identical? Different?
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Which set is more diverse in terms of ‘feel’?
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Which more diverse in terms of shape?
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Which would allow you to build more diverse shapes &
surfaces?
Mutation--not always
bad
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While the comparison is often made, proteins are not
sentences
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An amino acid is a collection of properties; changing from
one to another changes a region of the protein by
(little/some/a lot/completely)
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It’s an exaggeration, but think of amino acids more like
different vacuum cleaner nozzles
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How does a codon ‘mean’
an amino acid?
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Walking the walk
How bio machines translate the language of
nucleotides into an amino acid string
Translation Key Players –
define with a partner
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RNA polymerase (important in transcription but necessary for the
prep of translation)
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mRNA
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tRNA
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Aminoacyl tRNA synthetase
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Ribosome
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Termination factor
DNA template strand
5’ CTTAAATCCGAATGCCCATG 3’
How should the complimentary strand go?
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DNA template strand
(alternate version)
5’ CTTAAATCCGAATGCCCATG 3’
5’ end is pointy/spiky
3’ end is soft/furry
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Roles--for single
mRNA
5’ end is pointy/spiky
3’ end is soft/furry
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4 tRNA (8 pp)
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4 pairs to be synthetases (8 pp)
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1 small ribosomal subunit x 1 person
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1 large ribosomal subunit x 1 person
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2 to be (RNA polymerase & the RNA it makes )
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1 termination factor (1 person)
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Learning your ‘lines’
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Handout: Each group find questions related to their role;
answer them
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Lab manual, textbook, internet OK as sources
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RNA polymerase answer mRNA questions
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Meet your blocks-- 5’ is the end that sticks to hair, socks,
shirts
5’ end is pointy/spiky
3’ end is soft/furry
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Special powers
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Recall that ribosome assembly is the result of methionine
tRNA finding a match on mRNA in presence of small
ribosome subunit
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Only methionine tRNA (it will ‘know itself’ once crowned by
the synthetase that hands out met) can team with small
ribosomal subunit & join with the ‘AUG’!
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Choreographing
translation
A play of many parts, many players, no
brains
Going with the flow
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mRNA at the central bench
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ribosome assembles around it
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synthetases at bench corners (or ‘diffuse’ opp. direction vs. tRNA)
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tRNAs will ‘diffuse’ by following a path through the room
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When any event first happens*, action stops, molecules involved
will announce, explain
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Go until a protein happens
*This includes non-events (rejections, etc.)
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Walk-through with 1 tRNA
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Everybody watches visits to synthetase, ribosome
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In the real world, everything is happening all the time;
all is happenstance
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Who knows the code?
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What happens if a tRNA carries the wrong amino
acid?
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What happens if the mRNA contains a copy error
relative to DNA?
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What happens if a tRNA has a mutated anticodon
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Review movie
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http://www.youtube.com/watch?v=-zb6r1MMTkc
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Meet your
semester-long
interest
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Semester Project
❖
Desktop Lab 4
❖
Perform the experiment with a group
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For the next week or so, come up with hypotheses for what
is going on, think about ways to test this phenomenon
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Homework
StructViewer*--amino acid look & feel**
Begin thinking about your project
Assessor: mutation & translation
*As will always be the case in this course, no tricks; focus on the primary idea(s)
**‘SurfaceViewer’ link from Software page may help
...Ch. 3 reading about the immune system is just for fun