BSCI 230 Today, 9 May 2001

Exam 3 returned next Tuesday in lecture


Requests for regrades for this exam will be done in writing:

A typed (TYPED) document, 12 pt font
No more than 2 questions and 15 total lines
Submit at beginning of final exam on 5/22

Final Examination:
Tuesday, 22 May @ 1:30 - 3:30 PM
In BPS 1240 (right here)

(For gosh sakes, do not be among the missing!  I must turn in a grade and….)



BSCI 230 Today, 15 May 2001 - Lecture 24 --- 25


First, let me thank all of you for a most enjoyable semester.  You have made my decision to leave administration and to return to the classroom so much easier. A very special thank you to those who gave in class performances, agreed to trade barbs with Dr. K-I-A for the good of the claas, and who weren’t afraid to speak up.


Exam 3 Recap:


First, many folks did very poorly.  Some adjustment may be necessary at the end, but it is in your best interest to do well on the final to make it easy for Dr. K-I-A to give you the benefit of the doubt.


Question #1:  This muscle needed large tension, rapid contraction, but had to undergo a significant change in length.  So you build it striated, thick (parallel sarcomeres), and long (sarcomeres in series).  You also can’t have much passive tension until the muscle reaches its longest working length.  Many folks did not read the question and failed to put the L and S indicators on the graph. It was not the resting length!!!!!  For the final graph, many of you gave me the three graphs which were the basis for the one I asked for.  If you read the axes labels, any other answer wouldn’t make sense.  The final part was simply the MLCK story regurgitated.


Question #2:  Aaaarrrgggghhhh!  Right off an old exam!!!!!!


Questions # 3, 4, 5 & 6:  Simple return of information.


Question #7:  Structure - function!  How many times did we draw and discuss the need for a loooooong action potential in cardiac muscle, its causes, and the reasons for it?


Question #8:  Were you worried when all but one was increase??????


Your Final Exam:

Questions taken from previous examinations (modified slightly)
·  Molecular structures
·  Nernst/Goldman Vm question
·  Enzyme kinetics
·  Metabolic reactions
·  Photosynthesis
· Your Final Exam
·  Membrane Transport
·  Second messengers
·  Muscle contraction
·  Know your Up - Downs!!!


Approximately 35 points out of 200 will be on last three lectures


Also note the following questions based on the last lecture (that I never got to deliver):

(Don’t panic!  The answers to these two questions are taken right from some of the figures in the text and are a final parting gift to those who learn this material.  These two questions WILL be on the test verbatim.)

#1.  Explain how a protein destined for inclusion in an intracellular secretory vesicle reaches its destination via cotranslational import.  Begin with a nascent polypeptide being translated on a ribosome and detail the remaining steps.

#2.  Draw a picture of a polypeptide destined for the intermembrane space of a mitochondrion.  Include all relevant sequences.


Other Things To Know:

Structure of prokaryotic ribosome
Start and stop sequences
List from DNA & RNA
Structure of mRNA from Prokaryotes and Eukaryotes
Codon - Anticodon pairings


The final two lectures included references to the following figures from the text:

FIG 19-17, 19, 22, and 23
FIG 20-1, 4, 5, 6, 7, 8, 10, 11, 13, 14, 15, 16, 17, and 19.


Text from lecture slides:


IF2 & tRNAfMet

IF2 binds to 30S ribosomal subunit
mRNA also binds to 30S with purine sequence (often AGGA) upstream from Start codon
Binds to pyrimidine rich sequence in rRNA
IF2 insures that tRNAfMet binds


Thus IF2 insures that fMet is first amino acid

This ensures that the amino group is blocked so peptide bonds can be formed only at carboxyl end
fMet is often removed enzymatically


Cotranslational Import

ER Signal Sequence on polypeptide being synthesized
Directs mRNA - ribosome - polypeptide complex to bind to surface of rough ER
Signal Recognition Particle (SRP)
6 polypeptides and 7S RNA
Binds to polypeptide and stops further translation
Docks complex with ER membrane


Thank You &Fond Farewells

Lorri-Anne - Your Web Page Guru
Your Graduate Assistants
Your Recitation Leaders
Our Lone CHEM major (and friends)
Emily, our scribe
The Front Row
And to the rest of you for an enjoyable semester