Free BACE Chemistry and Biochemistry Questions and Answers 3

Question 1

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

Accepted Answer

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

Answer

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.

Question 2

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

Accepted 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

Answer

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.

Question 3

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

Accepted Answer

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

Answer

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.

Question 4

In biochemistry, what is competitive inhibition of an enzyme?

Accepted 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

Answer

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.

Question 5

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

Accepted 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

Answer

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.

BACE - Biotechnician Assistant Credentialing Exam Practice Test

BACE - Biotechnician Assistant Credentialing Exam Practice Test

Free BACE Chemistry and Biochemistry Questions and Answers 3