advanced phis

What are enzymes?

Proteins that catalyze the thousands of chemical reactions that constitute metabolism.

What is the function of actomyosin ATPase?

It is the enzyme that causes ATP production.

What happens when acetylcholine is released at the neuromuscular junction?

It triggers a series of events that leads to muscle contraction.

What role does ATP play in muscle contraction?

ATP powers the contraction process, allowing myosin heads to bind to active sites.

What are the two types of reactions based on energy change?

Irreversible reactions, which have a large energy change, and reversible reactions, which establish equilibrium.

What are essential amino acids?

Nine amino acids that cannot be synthesized by the body and must be obtained through diet.

What is feedback inhibition?

Inhibition of an allosteric enzyme by a product of its reaction, helping to regulate metabolic pathways.

What does lactate dehydrogenase do?

It converts pyruvate to lactate to generate ATP under anaerobic conditions.

What is the difference between active transport and facilitated diffusion?

Active transport requires energy and moves substances against their concentration gradient; facilitated diffusion does not require energy and moves substances down their gradient.

What is the role of buffers in the body?

Buffers resist changes in pH, helping to maintain body pH through absorption of protons or reduction of OH- effects.

What is anaerobic glycolysis?

The process where pyruvate is converted to lactate without the need for oxygen, producing ATP.

What are competitive inhibitors?

Substances that resemble normal substrates and compete with them for binding to the active site of an enzyme.

What are the four products of metabolism?

Carbon dioxide (CO2), water (H2O), adenosine triphosphate (ATP), and heat.

What is the Bronsted-Lowry definition of an acid and a base?

An acid is a proton donor, and a base is a proton acceptor.

Define entropy in thermodynamic processes.

Entropy is a measure of energy dispersal; processes occur spontaneously if they have a positive ΔS.

What is the importance of temperature in enzyme activity?

Temperature increases reaction rates until a point where high heat disrupts enzyme conformation and reduces activity.

What distinguishes aerobic from anaerobic glycolysis?

Aerobic glycolysis requires oxygen to completely break down pyruvate, while anaerobic glycolysis converts pyruvate to lactate without requiring oxygen.

What is the structure of an amino acid?

An amino group, carboxyl group, alpha carbon, and variable side chain.