Amino Acids and Proteins Flashcards
Enzymes
catalysts, speed the reactions up
Hormones
control physiological processes
Amylase, lipase, pepsin
Digestive enzyme
Hemoglobin
Transport substances by blood
Actin, tubulin, keratin
Structure/cytoskeleton
Insulin, glucagon
Hormone signaling
Antibodies
Defensive mechanism
Myosin
Carry out muscle contraction
Albumin (egg white)
Provide food for the embryo
Denaturation
Changes in temperature or pH may disrupt protein’s shape, funtionality.
Amino acids
Monomers that makeup proteins
NH2
Amino group (protonated, positive charge)
COOH
Carboxyl group and a hydrogen atom (deprotonated, negative charge)
Nonpolar, Nonaromatic Amino Acids
Hydrophopic (hate H2O)
Aromatic Amino Acids
Can absorb UV light/ determining protein concentration via spectroscopy
Polar Uncharged Amino Acids
hydrophilic (H2O loving)
Charged Amino Acids
Can be divided into acidic (- charged) and basic (+ charged) amino acids
Essential Amino Acids
Can not be synthesized by the human body, obtained from the diet
Non-Essential Amino Acids
Can be synthesized by the body
Phosphorylation
Phosphate groups, signaling pathways
Glycosylation
Carbohydrate groups, affecting protein folding, stability, cell recognition
Acetylation and Methylation
Occur on lysine, influencing gene expression
Ubiquitination
Attachment of ubiquitin to lysine residues, tagging proteins for degradation
Primary structure (Protein)
The sequence of amino acids in a polypeptide chain
Secondary structure (Protein)
Folded structures that form within a polypeptide
α helix
The carbonyl (C=O) is hydrogen bonded to the amino H (N-H) of an amino acid that is four down the chain.
β pleated
Polypeptide chain line up next to each other, forming a sheet-like structure held together by hydrogen bonds. (the R groups extend above and below the plane of the sheet)
Tertiary structure (Protein)
The overall three-dimensional structure of a polypeptide, most proteins have.
Disulfide bonds (safety pins)
Covalent linkages between the sulfur-containing side chains of cysteines
Quaternary structure (Protien)
Subunits, protein consisting of more than one amino acid chain. DNA is composed of ten subunits
Denatured proteins
Turn back into an unstructured string of amino acids
Hydrophobic interactions
Non-polar amino acid side chains tend to cluster together inside the protein, release water, increasing the entropy of the system.
Hydrogen bond
Form between polar side chains and contribute significantly to the protein’s stability
Ionic bonds (Salt bridges)
Form between positively charged (basic) and negatively charged (acidic) side chains
Van der Waals forces
low fluidity of cell membranes
Entropic (Randomness)
Protein folding is driven by a balance of enthalpic and entropic changes
Conformational entropy
Decreases its conformational entropy/ offset by other entropic gains
Solvent entropy
When hydrophobic chains cluster –> water being release –> increases the entropy of the surrounding water molecules
Molecular Chaperones
Preventing improper interactions that can lead to aggregation or misfolding
Chaperonins
Cylindrical complexes that provide a protected environment for protein folding
