CH3 | Proteins (1/2) Flashcards
Amino acids are the building blocks of…
proteins.
How many naturally occurring amino acids are there?
20.
The common structural features of amino acids are…
amino group (-NH2), carboxylate (-COOH) and hydrogen bonded to the same carbon atom.
Amino acids differ in their…
R group.
In the amino acid, the amino group is..
basic.
In the amino acid, the carboxylate group is…
acidic.
Protein primary structure is the exact order of…
amino acids in the chain.
The primary sequence determines the protein’s…
final fold and function.
Any change in primary sequence changes the…
entire protein.
What type of bond maintains the primary structure of a protein?
Covalent, peptide bonds.
Peptide bonds occur between which two groups of adjacent amino acids?
Amino and carboxyl.
Intramolecular bonding refers to…
bonds that occur within the atoms of the SAME molecule.
Intermolecular bonding refers to…
bonds that occur between ADJACENT MOLECULES.
Secondary structure refers to local folded structures within a polypeptide due to interactions between…
atoms of the backbone (without R group).
The most common secondary structures are…
α helix and β pleated sheet.
The α helix is stabilized by what type of bonds?
Hydrogen bonds.
Hydrogen bonds in α helix occur between which groups?
Amide (>N-H) and carbonyl (>C=O) groups.
An amide and carbonyl group that are hydrogen-bonded are how far apart on the amino acid chain?
4 amino acids.
How many amino acids are there in every twist of the α-helix?
3.6 amino acids.
Naturally occurring α-helices in proteins are…
right-handed.
An α-helix can be formed from how many polypeptide chains?
One (single chain).
Hydrogen bonds in α-helix are… (intermolecular or intramolecular)
intramolecular.
β-sheets are formed when two (or more) different regions of the polypeptide (____ amino acids long) lie side-by-side.
usually 3-10.
In β-sheets, hydrogen bonds form between which groups?
(C=O) and amino H groups of the backbone.
In β-sheets, the R groups extend…
above and below the plane of the sheet.
The strands of a β pleated sheet may be…
parallel or antiparallel.
How many beta-strands are necessary to make a β-sheet?
two or more.
In β pleated sheet, hydrogen bonds are… (intermolecular or intramolecular)
intermolecular.
Tertiary structure is the overall…
3D structure of a polypeptide.