Unity of Life/Biomolecules
What are the 3 domains of life?
Bacteria, Archaea, Eukarya
Name the three types of van der waal forces
Dipole-Dipole
Dipole-Induced dipole
Induced dipole - Induced dipole (LDF)
What are the four groups attached to the α-carbon of a typical amino acid?
Amino group, Carboxyl group, Hydrogen, R-group
Primary, Secondary, Tertiary, Quaternary
Which is stronger, covalent or hydrogen bonds? Why?
Covalent because electrons are shared.
What are the four dominant elements found in the 3 domains of life?
Carbon, Hydrogen, Oxygen, Nitrogen
Hydrogen bonds form between which functional groups?
Alcohols, Aldehydes, Ketones, and NH groups (C-H bonds do not form H-bonds)
How many times more protons does lemon juice (pH=2) have than blood (pH=7)?
100,000
When proteins are denatured, they return to which structure?
Primary
Do all amino acids have a chiral carbon? If not, which one(s) does not?
No, glycine does not have a chiral carbon
Which type of biomolecule does not polymerize?
Lipids
What is the difference between enthalpy and entropy?
Enthalpy: the system's internal energy and the energy associated with its pressure and volume
Entropy: the measure of randomness in a system
What is the pH range of the zwitterion form of an amino acid?
Between 2 and 9
What type of interaction primarily stabilizes the α-helix and β-sheet of a protein?
Hydrogen bonds between the protein backbone
What happens to the concentration of H+ protons when pH increases?
The concentration decreases
Name the four major biomolecule monomors and the polymers they form
Carbohydrates - polysaccharides
Amino acids - proteins
Nucleotides - nucleic acids
Lipids - none
What is the tendency of nonpolar molecules to associate in water?
Hydrophobic effect
What is the A-/HA ratio of acetic acid (pKa=4.76) at pH 5?
1.74
A mutation changes one amino acid in a protein's primary sequence. Why could this change the protein's overall 3-D shape?
primary structure dictates the protein's native conformation. Changing an amino acid can change the interactions responsible for folding.
A protein is placed into an environment where its hydrophobic amino acid side chains are exposed to water. What would you predict the protein will do, and why?
The protein will tend to fold so that hydrophobic side chains are buried inside, while more polar/charged groups are exposed to water.
Why is carbon well-suited for forming the necessary molecules for life?
Carbon can form four covalent bonds, allowing it to create chains, branches, rings, and complex 3-D structures.
What two processes are powered by the hydrophobic effect?
Membrane formation
Protein folding
Determine whether each amino acid is likely to be found on the interior or exterior of a protein: Valine, Leucine, Glutamate, Histidine.
Valine - interior
Leucine - interior
Glutamate - exterior
Histidine - exterior
How would you best describe the structural characteristics of α -keratin? (4)
Pairs of α -helices
Form coiled coils
Coiled coils held together by disulfide bridges
Rich in hydrophobic residues
An amino acid has a carboxyl pKa of 2 and an amino pKa of 9. What is its predominant net charge at pH 7?