LS1a Final Review
Cylindrical lipids (two tails) form a phospholipid bilayer that spontaneously forms into a sealed
compartment because of the amphipathic nature and the aqueous environment.
Laterally diffuse, rotate, flex, and flip-flop (rare).
LS1a Final Review
o Amino acids are chiral in structure
o Peptide bonds are shorter than normal single bonds and have a high barrier to rotation.
Resonance stabilization between carbon and nitrogen with 40% in double bond s
Function and Structure of HIV Protease
Protease split large 3 polypeptides through catalysis of peptide amide bond (scissile
bond) hydrolysis to make the future proteins of the virus.
Active site contains asp-thr-gly. Aspartic residues at i
Depolymerize after vesicle has formed with specific cargo so as not to get in the way of
o Clathrin (made of triskelions that make spherical structure) plasma membrane
for secretion and some proteins to endosomes.
o COP I _ Golgi to ER
o COP II ER
Peptidyl transferase: peptide bond formation catalysis in large ribosome subunit RNA.
Transfers growing chain from P site to amino acid A site, creating a peptide bond.
Mediates nucleophilic attack on carbon center of carboxyl group attached to tRNA in P
tRNA exits E site. Shift is catalyzed by protein EF-G, involves hydrolysis
of a molecule of GTP.
To stop translating, release factor recognizes stop codon and catalyzes the
release of completed polypeptide chain.
Bacteria: E coli and Lac Ope
Splicing: 2 trans-esterification reactions, catalyzed by spliceosome.
1) 2 hydroxyl of branch point adenosine attacks phosphorous at 5
splice site. Intron forms a lariat loop and sugar phosphate
backbone is broken between intron and exon 1. 2) free 3 OH
Takes place in a moving bubble with the strands re-annealing as growing transcript is
Template strand changes, depends on gene.
Promoters located at -10 (TATAAT) and -35 (TTGACA) are recognized by
sigma factor. Strong
information. Chromosomes allow for orderly packing of large amounts of DNA. Wrap around 8
histones to form nucleosomes.
Change G rxn= -2.7, Keq=100
Decide between conservative and semi conservative by using e coli in N15 a
Concentration gradient: difference in concentration across bilayer.
Membrane potential: any difference in charge across membrane. Cell
slightly negative from movement of potassium ions across membrane
through potassium leak channel (resting membrane poten
Kinase Cascade: Active Ras interacts with other proteins that have kinase activity,
relaying the signal to a set of protein kinases in the cytoplasm.
o MAPKKK, MAPKK, MAPK, gene regulatory protein (influence which genes are
transcribed/which proteins are
Both drug and protein binding pocket must lose interactions with water
(desolvation) when forming a complex with each other. Interactions must
be more favorable than lost enthalpic interactions with water.
Drugs: multiple distinct small-molecule structure