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What can proteins do?
latch on to substances that are not soluble to help transport them
What can amino acids form and why?
Can form isomers but only two can get incorporated into proteins
What is the backbone of amino acids?
Explain the groups.
anything but the R group
two are ionizable -- they have a proton that they aren't permanently attached to (the primary amino group and the primary -COOH group)
Explain the groups in terms of pH.
In acidic solutions, COOH is constantly letting go of its proton. However, it is being reprotonated just as quickly. At a higher pH, (2-4), this reprotonation ceases; and, the amino acid exists as a zwitterion.
If we are taking an ionizable group through titration, what is happening?
protons are being pulled away from these groups as --OH scavenges for H+ to form water
describes the strength of an acid
describes the susceptibility of a proton to removal by reaction with a base
Why are there three letter abbreviations and one letter abbreviations?
Three letters: RNA reads it in three nucleotides (codons)
One letter: condenses protein structure
In acid, how does an amino acid exist?
with both ionizable groups protonated
In base, how does an amino acid exist?
with both ionizable groups deprotonated
An increase in pH from acid causes?
the formation of a carboxylate
What is the inflection point? What occurs at it?
A point on a chart that marks the beginning of a significant move, either up or down
the amino acid form changes from either protonated--> zwitterion or zwitterion--> deprotonated
In acid base chemistry, what is the proton donor? proton acceptor?
- proton donor: acid
- proton acceptor: base
Definition of pH
pH=log(1/[H+])= -log [H+]
Definition of pKa (formula)
At the halfway point, what is occurring?
the concentration of conjugate base equals that of the acid
What are some functions of proteins?
- conversion of energy
- muscle contraction
- structural support
- immune response
- growth and development
__ is the most abundant protein.
__ and __ function in structural support.
collagen and keratin
What is the difference between secondary and tertiary structure?
secondary: interaction is localized; between adjacent amino acids
tertiary: different regions will react together
What is quaternary structure?
multiple subunits brought together
How many atoms are involved in amino acids?
- five: -NH3+
- - COO-
- alpha carbon
How many different R groups are there?
20, but glycine has just a simple hydrogen, so technically nineteen