Transcript Ribosome and Introduction to DNA Forensics

Announcements
Today (Wednesday) – quiz on Chpt 2 of ECB
HW #3, Assigned today, due next Wednesday; Chpt 3 of ECB
Today’s Lecture: Anne on Ribosome;
Paul on Applications of DNA: Forensics, FISH, DNA “chips”
Last time: I assigned you read “Predictable Packaging,” by Tim Richmond
Commentary about Widom et al, Nature, 2006 and to write-up a ½-1 page
summary! (Due next Monday).
Do NOT do this. Instead focus on:
Due on Monday: Your article on what you will give your talk and research paper. Turn
in the original research paper; also turn in the title of a review paper that gives
background on the general subject; also, the title(s) a general (biophysics) book/web
pages (e.g. Wikipedia pages) that gives a more general background. In general, an
original research article has LOTS of terminology that you must learn first, before you
even have a hope of understanding it!
You can pick articles from Nature, Science, Cell. You do NOT need to pick from these,
but it does assure you that the article is important
½ pg write-up. Including why it’s of interest to you, why it’s generally of
“widespread” interest.
Thursday, 4 pm, Rm 141 Loomis– Physics Colloquium—Me!
Quiz #2: ECB Chpt 2
the gain or loss
1. Ionic bonds are formed by ________________of
electrons by an atom. Covalent
bonds form by ________________
of electrons.
the sharing
2. Cells contain four major families of small organic molecules, what are they?
1.____________
2. nucleotides
__________________3. ________________4.
__________
Sugars
fatty acids
amino acids
3. Each family in question #2 (above) can be used for 3 things. They are:
__________________________________________________________
1.
3. An energy source
Storage of information 2.
Signalling
4. The __________
bilayer forms the structural basis for all cell membranes.
lipid
5. In order to make long polymers of sugar, two monomers can be brought together
by enzymes such that their hydroxyl groups (-OH) couple together. This catalysis is
condensation
an example of a ____________________
reaction.
Anne Cai, my TA, presents on Translation and the Ribosome
Translation
Stages in translation
•
•
•
•
Initiation
Elongation
Termination
Recycling
Initiation
• mRNA binds to small subunit of the
ribosome (30S)
• fMet-tRNA binds to the P site of the
ribosome
• Initiation factors (IF1, IF2 and IF3) help to
assemble the initiation complex.
Elongation
Termination and Recycling
Ref: Thomas A. Steitz, A structural understanding of the dynamic ribosome
machine. Natue Reviews Molecular cell biology, Volume 9, 243. (2008)
•
•
•
•
•
IF1, IF2 and IF3: initiation factors
EF-Tu and EF-G: elongation factors
RF1, RF2 and RF3: release factors
RRF: ribosome recycling/release factor
GTP: Guanosine triphosphate
Discussion of movie on translation: (Venki Ramakrishnan's, 2009
Nobel Prize Winner) home page. http://www.mrclmb.cam.ac.uk/ribo/homepage/mov_and_overview.html
The movie is actually pretty long including the initiation, elongation, termination and recycling stage.
(Paul’s turn:) Intro to DNA Forensics
Every person has their own, unique DNA
(except for twins).
A person can be “tagged” with their DNA.
If your blood, semen is found you’re in trouble.
Your genes found in a kid  parent.
You’re killed in war/car accident and can only recognize
you from your DNA.
Don’t have to completely sequence their DNA.
Can find certain regions. Just enough –say 13 different
ones– that chances that another person has exactly the same
set is 1 in a trillion.
DNA in the Cell
chromosome
cell nucleus
Double stranded
DNA molecule
Target Region for PCR
Individual
nucleotides
Polymerase Chain Reaction. what is it?
Invented 1990; Nobel Prize in 1993: Kary Mullis
PCR, stands for?
DNA Amplification with the
Polymerase Chain Reaction (PCR)
5’
3’
5’
3’
3’
3’
5’
5’
Starting DNA
Template
Separate
strands
(denature)
Forward primer
5’
3’
5’
3’
Make copies
Add
primers
(extend
primers)
5’
(anneal)
3’
3’
5’
Reverse primer
PCR (Polymerase Chain Reaction) Copies DNA
Exponentially through Multiple Thermal Cycles
Original DNA
target region
1 copy
Heat
Oligo’s
DNA
Polymerase
dNTP
Cool
In 32 cycles at 100% efficiency,
Heat
Cool
2 copies
Heat
4 copies
…
?? billion copies are created
1.07
To work, what property of DNA polymerase have to have?
New
bugsinland
up in
court ... Microorganisms
hot
HeatScientists
stable (1998)…Yellowstone's
so don’t have to add
new
polymerase
for everyfrom
cycle
springs are especially valuable because their enzymes are not easily destroyed by heat. ...
Thermostable organisms, e.g. living in Yellowstone Geysers have this.
Class evaluation
1. What was the most interesting thing you learned in class today?
2. What are you confused about?
3. Related to today’s subject, what would you like to know more
about?
4. Any helpful comments.
Answer, and turn in at the end of class.