FREE BACE Chemistry and Biochemistry Flashcards

What is a buffer in chemistry, and why are buffers critical in biotechnology applications?

Answer: A buffer is a solution that resists changes in pH when small amounts of acid or base are added

Buffers resist pH changes by containing a weak acid and its conjugate base in equilibrium; they are critical in biotechnology because enzymatic activity, protein stability, and cell viability are highly pH-dependent.

What is the difference between substrate-level phosphorylation and oxidative phosphorylation?

Answer: Substrate-level phosphorylation directly transfers a phosphate group from a substrate to ADP; oxidative phosphorylation uses the proton gradient across the inner mitochondrial membrane to drive ATP synthase

Substrate-level phosphorylation directly phosphorylates ADP using a high-energy phosphate group from a metabolic intermediate; oxidative phosphorylation uses the proton gradient created by the electron transport chain to drive ATP synthase.

What is the role of disulfide bonds in the structure of proteins like antibodies?

Answer: Disulfide bonds form covalent cross-links between cysteine residues that stabilize protein tertiary and quaternary structure

Disulfide bonds (S-S covalent bonds between cysteine thiol groups) covalently stabilize protein structure, linking separate polypeptide chains or stabilizing loops within a single chain.

In biochemistry, what is competitive inhibition of an enzyme?

Answer: A molecule that resembles the substrate competes for binding at the active site reducing enzymatic activity but can be overcome by increasing substrate concentration

A competitive inhibitor structurally resembles the substrate and competes for the active site; increasing substrate concentration outcompetes the inhibitor, restoring Vmax while Km appears increased.

What is the difference between hydrophilic and hydrophobic amino acid residues in a protein and how does this affect protein folding?

Answer: Hydrophilic residues interact favorably with water and are found on the protein surface; hydrophobic residues avoid water and pack into the protein interior during folding

Hydrophobic residues with nonpolar side chains minimize contact with water by packing into the protein core; hydrophilic residues with polar or charged side chains interact favorably with water and face the exterior.

What is a recombinant protein and how is it produced in biotechnology?

Answer: A protein encoded by a gene that has been introduced into a host organism's DNA using recombinant DNA technology allowing production of specific proteins at scale

Recombinant proteins are produced by cloning the gene of interest into an expression vector, transfecting or transforming a host cell (E. coli, CHO, yeast), and allowing the host to express and produce the protein.