Protein and Amino Acids Flashcards

Flashcards covering key vocabulary and concepts related to protein and amino acid structure, function, and modification.

Proteins

Most abundant organic molecule that are very diverse and made of amino acids.

Enzymes

Catalyze biochemical reactions, speeding them up by finding a substrate to react with. Typically ends with -ase.

Hormones

Long-distance chemical signaling released by endocrine cells; can be peptide (protein-based, e.g., insulin) or steroid/lipid-based.

Hemoglobin

A transport protein that carries O2

Actin, tubulin, keratin

Structural proteins providing structure.

Antibodies

Proteins involved in defense mechanisms.

Myosin

A protein involved in muscle contraction.

Legume storage proteins, albumin (egg white)

Storage proteins.

Globular Proteins

Proteins like hemoglobin that carry O2.

Fibrous Proteins

Proteins like collagen found in the skin.

Amino acid

Monomer of a protein. Basic structure consists of NCC (N-terminus, Central carbon, C-terminus)

Polypeptide

One or more linear chains of amino acids.

N terminus

NH2- amino group

Alpha carbon

The carbon nearest to a function group that has a side chain and a hydrogen group.

C terminus

COOH- carboxyl group.

Pka

How strong is an acid or base (lower pka = strong acid).

R group

Identifies A.A.

Peptide bond

The bond formed between two amino acids during protein synthesis, releasing a molecule of water (always read N terminus to C terminus).

Essential amino acid

Amino acids obtained through diet (His, ile, leu, lys, met, phe, thr, trp, val).

Non-essential amino acid

Amino acids created by the body (Ala, asn, asp, glu, ser, arg, cys, gln, gly, pro, tyr).

Phosphorylation

Post-translational modification involving the addition of a phosphate (P) group, common on ser, thr, tyr.

Glycosylation

Post-translational modification involving the addition of a carbohydrate group.

Acetylation

Post-translational modification involving the addition of an acetyl group.

Methylation

Post-translational modification involving the addition of an alkyl group.

Ubiquitination

Post-translational modification involving the addition of ubiquitin to lysine for tagging and degradation.

Primary structure

Sequence of amino acids determined by DNA within a gene.

Secondary Structure

Held by hydrogen bonding, forming alpha-helixes or b-pleated sheets.

Alpha helix

A secondary protein structure with 3.6 A.A. per turn; r-groups facing outward

Proline

Alpha helix breaker, incompatible and bends.

B-pleated Sheet

A secondary protein structure where 2 polypeptide chains line up with R groups above and below the plane.

Tertiary structure

R group interaction ( every non-covalent bond, except peptide). Exists within ONE subunit. Hydrophobic interactions. Only 1 covalent: disulfide between cysteines

Quaternary structure

Has subunits (1+ polypeptide chains). Same as tertiary bonds but between subunits

Hydrophobic interactions

Non-polar a.a., hate water, cluster together. Nonpolar aggregate in center->Water is sent to environment -> system entropy increases.

Ionic bond/salt bridge

Positive charged (basic) + negative charged (Acidic) side chain.

Entropy

Measure of disorder in system

Denaturation

Native conformation (original) becomes non-native state (altered shape).