Bio 344
Molecular Biology
Old web site:
www.sbs.utexas.edu/herrin/
bio344/
Suggestions for success
1. Read the book as much as you can.
2. Print out the slides (1-2/page) and bring
them to lecture.
3. Take additional notes on the slides in
lecture (or tape the lecture).
4. Go to Discussion Sections to ask questions,
and take quizzes to test your understanding
and knowledge.
5. Don’t wait until the day before the exam to
cram.
Molecular Biology - what’s in a
name?
“Molecular Biology” was born in the
middle part of the last century as a new
discipline focused on understanding the
molecular basis of the most
fundamental of life processes – those
involving the reproduction and
expression of genetic information.
Molecular Biology Timeline
1869
1910
1941
DNA discovered by F. Meischer
Genes on chromosomes; T.H. Morgan
One gene-one enzyme, Beadle & Tatum
1944
1953
DNA is genetic material; Avery, Mcleod& McCarty
1961
Discovery of mRNA; Brenner, Jacob & Meselson
1966
Finished unraveling the code; Nirenberg & Khorana
1972
Recombinant DNA made in vitro; P. Berg
DNA cloned on a plasmid; H. Boyer & S. Cohen
Discovery of reverse transcriptase; H. Temin
Rapid DNA sequencing; F. Sanger & W. Gilbert
Discovery of split genes; Sharp, Roberts et al.
1973
1973
1977
1977
1982
1986
2001
Structure of DNA; Watson, Crick, Franklin, Wilkins
Discovery of ribozymes; T. Cech & S. Altman
Creation of PCR; K. Mullis et al.
Human Genome Project; Venter, Collins and
many others
The modern framework of
Molecular Biology
Transcription
DNA
Replication
& Repair
Processing
preRNA
Translation
RNA
Protein
folding
assembly
processing
DNA
RNAs and proteins mediate these processes.
Molecular Evolution
•
What was the first informational
macromolecule?
–
–
–
–
Proteins ?
DNA
?
RNA
?
Macromolecule no longer used in modern cells ?
RNA is the only currently-used macromolecule
that is both a carrier of genetic information and
an enzyme.
The RNA World
• The “RNA world” hypothesis posits that there
was a stage early in the early evolution of life
that was dominated by RNA.
• Corollary: the functions of RNA in modern
cells are only remnants of its previous roles.
Possible remnants of the RNA World
1.
2.
3.
4.
5.
Self-splicing introns
Rnase P (ribozyme that cleaves tRNA precursors)
Self-cleaving viral RNAs
Peptidyl transferase in the ribosome
Nucleotides (ribo) involved in:
– metabolism (e.g., ATP, UTP, NADH, NADPH)
– signaling (cAMP, cGMP, GTP, ITP)
– assembly of complexes (GTP and ATP)
– Energy for motility, ion pumping, etc. (ATP,
GTP)
Molecular Biology & the Origin
of Life
• Can we reconstruct a living, reproducing
cell from molecules using the tools &
concepts of molecular biology?