L1-2: The Building Blocks of Life Flashcards
What are the 20-22 amino acids?
Alanine, Asparagine, Arginine, Aspartic acid, Cysteine, Glycine, Glutamine, Glutamic acid, Histidine, Hydroxyproline, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Selenocysteine, Serine, Tryptophan, Tyrosine, Threonine, Valine
Which amino acids are charged?
-ive
Aspartic acid
Glutamic acid
+ive
Arginine
Histidine
Lysine
Which amino acids not directly encoded?
Selenocysteine and Hydroxyproline
What amount of a human is protein (dry weight %and wet weight kg)
~25% and 12kg wet
What is the approximate number of proteins in the human body?
20,000
What are the 4 levels of protein structure?
primary, secondary, tertiary and quaternary
What 2 structures are formed from secondary protein structure?
alpha helix and beta pleated sheet
What is the bond between amino acids called?
Peptide bond
What are the 2 classifications of amino acids?
L and D amino acids
How is the ribosome structured?
It has large and small sub-units
What would be stopped when protein synthesis is a drug target? And where would the target be?
Peptide bond formation and at the active site of the ribosome
Which type of amino acids do ribosomes make?
L-amino acids
Why are the bonds in a tetrahedral arrangement in amino acids?
To minimize overlap
What arrangement do electron shells adopt in proteins?
sp3 hybridization which is in a tetrahedron
What does it mean when a carbon is chiral?
The different chiral forms of a molecule cannot be superimposed on each other
How can you detect 2 different chiral molecules and what are they called?
Use plane-polarized light from a polarizer which rotates clockwise or anticlockwise and they are called enantiomers
What is L/D configuration relative to?
D-glyceraldehyde
What handed are alpha helicies?
Right handed
What is an example of a drug used that changed enantiomers in the body?
Thalidomide (late 1950s)
What are the amino acids with hydrophobic side chains?
Ala, Val, Ile, Leu, Met, Phe, Tyr, Trp
What is each amino acid in a sequence called?
A residue
What are the characteristics of the peptide bond?
Rigid and planar
What is electronegativity?
Attraction of different elements for electrons due to atomic number and distance from nucleus of valence electrons
What are the slight charges of the amide and carbonyl groups?
Amide- positive
Carbonyl- negative
Why are hydrogen bonds important?
Secondary structure arises from backbone hydrogen bonding and higher level structure has large hydrogen bonding contribution
how many residues per turn are there in a 100 degree repeat?
3.6
What amino acids are preferred in alpha helices?
Ala, Glu, Leu, Met, Ile, Lys, Phe, Trp
On average, how many residues do alpha helices contain?
11
How many residue repeats do beta strands have?
2
What are the preferred amino acids in beta strands?
Ile, Tyr and Val
What type of handedness do beta pleated sheets usually have?
Right-handed twist
What do beta-sheets often form?
The core of globular proteins
