Biophysics

7/16/2021

Numbers:

Large Numbers

Aren't really affected by small multiplication, subtraction, division or something like that

Very Large Numbers

Think the amount of atoms in the human body
- Your body isn't going to die if you lose 100-even 100,000 atoms. Unless they're super important ones of course. But you get the memo.
When you get to ridiculously large numbers like 2^(6*10^23)
- The only thing that really matters is the exponent. Multiplying by a constant will literally do nothing

Differences between prokaryotic vs eukaryotic cells

Prokaryotic vs Eukaryotic:

Everything is in a soup, soup = cytoplasm
- Eukaryotic cells have membrane bound organelles while prokaryotic cells do not

What is a Protein and How is it Made?

Proteins are large complex molecules that play many critical roles
Proteins are built form chains of building blocks called amino acids
- there are 20 amino acids

Characteristics of the Genetic Code

Amino Acids:
- Triplet Code: 3 bases = 1 Amino Acid
- Non-overlapping
- Nearly Universal (exception: archaea)

RNA to protein Translation Steps (Computer Instructions)

Biomolecules

Key: Interaction with water

Detergents:
- Are Amphiphilic Molecules
  - Head polar and likes water
  - Oily Hydrocarbon ails

Dirt: oily material
Soap: Soap Bubbles
- Thin layer of water
- Layer is roughly the same as wavelength of light ~ 500nm
Lipids can self organize into structures like micelle or soap bubbles
Lipids: Amphiphilic
Water: membrane that compartmentalization
Water with lipid bilayer
Cells self-assemble and self-heal
- Cost of this is that it only works in narrow temperature range
DNA molecule: Gigantic in size
Sugar-Phosphate backbone
- Polar, likes water

Last week we discussed: Temperature, absolute Kelvin Temperature scale - KE Per Molecule is Proportional to Temperature

Background radiation is 3 Kelvins

Biomolecules

Water:

Water is polar
Water is a universal solvent, however, details of solubility depends on polarity
- Hydrophilic: Likes/mixes with water
- Hydrophobic: Dislikes/does not mix water
- Amphiphilic: Parts that like and parts that dislike water.

Solid ice is lighter than liquid water

Ice floats on water
Origin of life:
- Ice insulated water, which allowed it to remain somewhat warm to form life underneath the ice layer

Water is a liquid at room temperature

Other small molecules: O2, N2, Co2, No, etc. all are gas of room temp
we expect small molecules to have low boiling points, but water has a rather high boiling point

Water has high heat capacity and (latent heat)

Adhesion and Cohesion Properties

Biomolecules

DNA Molecules:

Sugar phosphate backbone + hydrophobic bases

Width is 2x10^-9m

Chromosome has 10^9 bases, roughly 2meters long