Proteins Flashcards
What is the importance of proteins?
They have a very wide range of functions. Each one has a complex three deimensional shape (conformation)
What is the structure of an amino acid?
Consists of 4 parts surrounding a central carbon: amino group (NH2), carboxyl group (-COOH), H atom, and a variable group (R).
What does the variable group do in an amino acid?
Determines the amino acid properties (Ex. polar (hydrophylic), nonpolar (hydrophobic), acid or base.
How are polypeptides formed?
Formed by condensation reaction.
What is the importance of the primary structure in a protein?
Each type of protein has a unique primary structure of amino acids. This sequence will determine the 3-D conformation.
Describe the secondary structure.
Coils and folds (due to hydrogen bonds at regular intervals along molecule)
Describe the tertiary structure.
Overall 3-D shape (conformation) of polypeptide.
Contortions in tertiary structure from R group bonding are due to what?
Hydrophobic interactions (nonpolar side chains), disulfide bridges (strong covalent bonds between sulfhydryls of cysteine), hydrogen bonds (between polar side chains), and ionic bonds (charged side chains).
Describe quaternary structure.
2 or more polypeptide chains aggregated into 1 macromolecule.
What are the general functions of a protein?
Structural, transport, muscle contraction, defense, cell adhesion, tensile strengthening, DNA packaging, hormones, receptors, catalysis (enzymes).
What is the function of the protein Rubisco?
Carbon fixation during photosynthesis.
What is the function of the protein Insulin?
Hormone that regulates blood sugar by signaling glucose uptake by cells.
What is the function of the protein Immunoglobulins?
Antibodies - specific immunity
What is the function of the protein Rhodopsin?
Pigment that absorbs light in rod cells of retina.
What is the function of the protein Collagen?
Forms a strong mesh of fibers in body (in skin, blood vessel walls, ligaments, bones, etc.)
What is the function of the protein spider silk?
Strong fibers for forming webs.
What is proteome?
All the proteins produced by a cell, tissue or organism at a given time. Every individual has a unique proteome.
What are enzymes?
Catalystic proteins that change the rate of reactions without being consumed. Enzymes lower activation energy.
What is activation energy?
The amount of energy necessary to start a reaction. (The energy required to break bonds in reactants).
What is a substrate?
An enzyme reactant.
What is an active site?
A pocket or groove on an enzyme that binds to substrate (i.e. the spot on the enzyme where the reaction occurs).
What is the induced fit model?
Enzyme and substrate fit together, but enzyme conforms to substrate.
What is one function of enzymes in regards to metabolism?
Enzymes control metabolic pathways.
What can affect enzyme activity?
Temperature, pH, and Substrate concentration.
