by Jonathon Sullivan MD, Ph.D.
FUNDAMENTALS III:
MOLECULAR BIOLOGY FOR THE COMPLEAT IDIOTE

Well, it’s time to delve even deeper into the workings of living matter. Your old Quantum Butcher has covered a lot of ground in the last two Fundamentals installments, and I strongly recommend that you check them out before you move on to the current offering, because things are starting to get just a little hairy. This will be the longest Fundamentals yet, and probably the most challenging. I’d recommend that you don’t try to do it in one sitting, and that you read it at least twice. Because this time, we’re diving headfirst into the world of molecular biology.

(synopsis)

back to QM home page   on to the next page!

WHATS THE FABRIC OF YOUR GENES?

Proteins as the genetic material?
DNA is the stuff of genes

FORMATTING LIFE'S HARD DRIVE: THE STRUCTURE OF DNA AND RNA

the structure of nucleotides
nucleotides are assymmetrical

Strung out on Acid- The Formation of DNA and RNA

linking nucleotides to form nucleic acids
nucleic acids are formed by polymerases
nucleic acids have sugar-phosphate backbones and two distinct ends

Zip it up: Base Pairing in DNA

Purines and pyrimidines
Hydrogen bonding and Watson Crick base pairing

Loosey-Goosey vs. Wound Too Tight-Comparing RNA and DNA

RNA tends to single strands
RNA can form secondary structures
DNA tends to antiparallel double strands
DNA forms a double helix
DNA structure enables it to function as the genetic material-

I'M NOT LIBERAL, I'M SEMI-CONSERVATIVE: DNA REPLICATION -

DNA Polymerase is a multi-enzyme complex with multiple activities-
Polymerase replicates in a bidirectional manner, creating a replication bubble -
Polymerase and other proteins create an open complex
Polymerase cannot initiate new strands and needs a primer
Polymerase can only read in the 3' to 5' direction
Leading strand and lagging strand
Okazaki fragments
Proofreading by polymerase

MY KARMA CAN TRANSFECT YOUR DOGMA-INFORMATION FLOW IN LIVING SYSTEMS

The Central Dogma of Molecular Biology
Most gene products are proteins
A few cracks in the Central Dogma

THANK GOD THE RUSSKIES DIDN'T CRACK IT FIRST: THE GENETIC CODE

The genetic code is a triplet code
The complete genetic code in table form
The genetic code is degenerate
The genetic code is universal

POLY, TAKE A MESSAGE: TRANSCRIPTION

A promoter element helps align DNA polymerase at the beginning of transcription
transcription is a highly regulated process
mRNA undergoes extensive processing after transcription

methylguanosine cap and polyadenylate tail
mRNA undergoes splicing to yield varying gene products from the same raw transcript
introns and exons--splicing adds a new level of control to gene expression

RIBO-ROBOTS ROCK - TRANSLATION

translation depends on transfer RNA
formation of the initiation complex
peptidyl transferase and the process of peptide elongation
animation of protein synthesis (translation) by the ribosome
some proteins undergo post-translational modification

HEY BOY! YOU LOOK MIGHTY GOOD IN THEM GENES! REGULATION OF TRANSCRIPTION

transcription is the most critical step for the regulation of gene expression
E. Coli and the Sugar Nazis--the lac operon

E. Coli has a polycistronic gene for mnching glucose
structure and function of the lac operon
lac operon animation

Regulation of Transcription is largely mediated through DNA-binding proteins
Bodacious TATA's: Regulation of Eukaryotic transcription

TATA-binding factors enhance transcription of euakaryotic genes
A web of transcriptional regulation

STUFF IT-THE PACKAGING OF DNA INTO CHROMOSOMES

supercoiling, histones and nucleosomes
10 nm filaments, 30nm solenoids, and toposiomerase II
chromatin and the cell cycle

HOW TO MAKE INSULIN FOR FUN AND PROFIT--A BRIEF INTRODUCTION TO RECOMBINANT DNA

endonucleases and sticy ends
plasmids--molecular trading cards for bacteria
making recombinant plasmids

FURTHER READING

BACK TO TOP