Amino Acids + Proteins Flashcards
- What are essential amino acids?
the a.a. that is not produced by the body, gained from a nutritional diet
- How many amino acids be found in the genetic code (made by cells)?
100 a.a present but only 20 a.a are found in protein synthesis
- What are the 4 groups bound to the carbon a standard amino acid molecule has?
- carboxyl group
- amino group
- R group
- H group
glycine is the only AA which doesn’t contain an alpha carbon
- What is a chiral carbon atom?
a carbon attached to 4 different sub groups
- What is an α-carbon atom?
attached to the carboxyl carbon, amino group, R and H group
- Which two stereoisomers of amino acids exist, and which is the predominate* form in proteins?
enantiomer and diastereomer
enantiomers represent AA which are building block of proteins. they are more predominate
- Why can amino acid (dissolved in water) act as base or acid?
due to the +1/-1 net charge from amino and carbonyl group respectively
zwitterion
- How does a peptide bond form?
A bond forms between the carboxyl C of 1st AA and amino N of 2nd AA.
-OH groups from carboxylic acid and H from NH2 is cleaved to form H2O as byproduct
- What is a tripeptide?
dipeptide + amino acid group
- What are two forms of amino acid interactions (out of 4)?
- Hydrophilic interactions (h-bonds – intermol. Forces)
- Hydrophobic interaction (intermol. Forces)
- Ionic interactions (intermol. Forces)
- Disulfide bond (intramol. Forces)
- What is the primary structure of a protein?
chain sequence of multiple groups of amino acids via peptide bond
- Which two types of secondary protein structures exist?
alpha helixes and beta sheets
- What is characteristic for an antiparallel β-sheet?
N-terminal and C-terminal run-in opposite directions
N-terminal is derived from the amio group (N-R) while the C-terminal is derived from carboxyl group (R-COOH)
- What is the tertiary structure of a protein?
A 3D structure of an entire polypeptide chain derived from primary and secondary structures
- What is an example of a protein in tertiary structure?
Rhodopsin
- What is quaternary structure of a protein?
A protein that consists of more than one amino acid chain
- What is an example of a protein in quaternary structure?
Hemoglobin
- Are fibrous proteins water soluble?
insoluble in water
- Name three classes of fibrous proteins (out of 4).
Microfilament
Intermediate Filament
Class 3
Septin (most recent)
- Which two fibrous proteins are found in the eye – and where?
collagen - cornea, sclera, iris
Keratin - cornea only
- Are globular proteins soluble in water?
soluble in water
- Name 4 functions of proteins in a cell with an example.
Structure – tissue and organ (cartilage, skin, bones and collagen)
Movement – Muscle, skin, bones
Transport – channels, pumps and carriers
Regulation/ Signaling – ligands bind to receptors
- What is the definition of a ligand?
A molecule bound reversibly by a protein
Any other molecule including protein, atom or ion
- What is the definition of a receptor?
chemical structure that receives and transduces signals to enable signaling
