5 Basic Cell Behavior Patterns:
Growth
Cell Division
Specialiazation/Differentiation
Movement
Interaction
What are the molecules that drive these processes?
Briefly Discusses the History of Molecular Biology:
The First defining moment was the the discovery that DNA was the genetic material.
The Second defining period was the discovery of the structure of DNA and then the elucidation of the mechanics of replication.
With this came the realization that the fundamental biological principles that govern simple organisms also apply to more complex organisms --- the details may vary though.
Model Biological Systems:
Viruses and Bacteriophage
Contain either DNA or RNA.
They are intra-cellular parasites -- they invade and take over other cells
Bacteria (Prokaryotes or Procaryotes)
Unicellular organisms, most are free-living but some are intracellular parasites
Contain a single DNA chromosome
No nucleus, No membrane-bound organelles
Rigid cell wall
Many Bacteria can be grown on "simple" media -- either liquid or solid media.
(the addition of "agar" will turn liquid media into solid media)
A simple minimal medium will contain ions and one simple carbon source such as a sugar or glycerol.
An organism that grows on such a medium is called a prototroph. Such an organism is capable of making all of its more complex molecules and "growth factors" from the simple precursors provided in the minimal medium.
Everything an organism makes generally is only made when it is needed -- regulation
If you have to add an additional organic nutrient in order for the organism to grow, then such an organism is called an auxotroph.
ie., an organism auxotrophic for vitamin B-12 or an organism auxotrophic for tryptophan.
Eucaryotes:
Fungi -- Yeasts and Molds
Protozoa
The fungi and the protozoa approach the complexity of animal and plant cells
Animal Cells -- brings up the ideas of differentiation, stem cells, immortality of tumor cells or transformed cells.
Plant cells
Methods of Molecular Biology:
Look over Table 1-1 on page 8
The Logic of Molecular Biology
Efficiency -- that natural selection in a competitive and resource limited environment has selected for simplicity....careful though....this may be a trap
Compare similar processes between species (phylogenetic history and parallelism)
Look for ways to measure (Quantitative assessment)
Make models and cartoons and use them to develop experiments
Comprehension based on experience and common sense:
Fisherman sees birds ---> infers that there must be fish present
What led us to infer that Sadam had weapons of mass destruction?
Experimentation
Chemical analysis has identified that there is lots of A, T, G, C present in purified DNA
Other analyses show that if you feed a cell radioactive ATP, 90% of it shows up in the nucleus of a cell.
So now you do an experiment --You give a mouse a big dose of radioactive ATP and you measure where it goes. Almost all of it ends up in the bone marrow and in the mucous epithelium.
What can you conclude from the above pieces of evidence????
Look at the diagrams in fig 1-5.