Enzymes and Digestion

Q: What is a monomer?

A: The single building block of a polymer (e.g., glucose, amino acid).

Q: What is a polymer?

A: A large molecule made of repeating monomers.

Q: What is hydrolysis?

A: Breaking polymers into monomers using water (used in digestion).

Q: What is dehydration synthesis?

A: Forming polymers by removing water.

Q: What are the 4 macromolecules?

A: Carbohydrates, proteins, lipids, and nucleic acids.

Q: What is the monomer of a protein?

A: Amino acid.

Q: What is the monomer of a carbohydrate?

A: Monosaccharide (simple sugar).

Q: What is the monomer of a lipid?

A: Glycerol + fatty acids.

Q: What is the function of carbohydrates?

A: Provide short-term energy.

Q: What is the function of lipids?

A: Long-term energy storage and insulation.

Q: What is the function of proteins?

A: Structure, enzymes, movement, and signaling.

Q: What are enzymes?

A: Proteins that speed up chemical reactions by lowering activation energy.

Q: What is a catalyst?

A: A substance that speeds up reactions without being used up.

Q: What is a substrate?

A: The molecule an enzyme acts on.

Q: What is the active site?

A: The part of the enzyme that binds the substrate.

Q: What happens to an enzyme when it denatures?

A: It loses its shape and can no longer function.

Q: What is the lock-and-key model?

A: The idea that each enzyme fits its substrate exactly like a key in a lock.

Q: What does "activation energy" mean?

A: The energy required to start a chemical reaction.

Q: How do enzymes affect activation energy?

A: They lower it, speeding up the reaction.

Q: Are enzymes used up in a reaction?

A: No, they can be reused.

Q: What are the 4 factors that affect enzyme activity?

A: Temperature, pH, substrate concentration, and salt concentration.

Q: What is an endergonic reaction?

A: A reaction that requires energy input.

Q: What is an exergonic reaction?

A: A reaction that releases energy.

Q: What happens to enzyme activity if temperature increases slightly?

A: It increases (faster reaction).

Q: What happens if temperature increases too much?

A: The enzyme denatures and stops working.

Q: What happens when temperature decreases?

A: Reaction slows down.

Q: What happens if pH or salt concentration changes drastically?

A: Enzyme activity decreases due to denaturation.

Q: What is a competitive inhibitor?

A: Molecule that blocks the active site, preventing substrate binding.

Q: What is a noncompetitive (allosteric) inhibitor?

A: Binds elsewhere on enzyme, changing its shape and stopping function.

Q: What are the four stages of digestion?

A: Ingestion, digestion, absorption, elimination.

Q: What is the difference between mechanical and chemical digestion?

A: Mechanical = physical breakdown; Chemical = enzymatic breakdown.

Q: Example of mechanical digestion?

A: Chewing or stomach churning.

Q: Example of chemical digestion?

A: Salivary amylase breaking down starch.

Q: What is peristalsis?

A: Wave-like muscle contractions that move food through the digestive tract.

Q: What is the correct order of digestive organs?

A: Mouth → Esophagus → Stomach → Small Intestine → Large Intestine → Rectum → Anus.

Q: What does the liver do?

A: Produces bile to break down fats.

Q: What does the gallbladder do?

A: Stores and releases bile into the small intestine.

Q: What does the pancreas do?

A: Produces enzymes for digestion and neutralizes stomach acid.

Q: What does the stomach do?

A: Uses acid and pepsin to start protein digestion.

Q: What does the small intestine do?

A: Finishes digestion and absorbs nutrients.

Q: What does the large intestine do?

A: Absorbs water and forms feces.

Q: What is the function of villi and microvilli?

A: Increase surface area for nutrient absorption.

Q: What is the pH of the small intestine?

A: Around 8; slightly basic for pancreatic enzymes.

Q: Where does most nutrient absorption occur?

A: Small intestine.

Q: What increases absorption efficiency in the small intestine?

A: Villi and microvilli.

Q: How are fats absorbed differently from carbs and proteins?

A: Fats enter the lymphatic system; others enter the bloodstream.

Q: What is bile’s role in digestion?

A: Emulsifies fats into smaller droplets for lipase to digest.

Q: What prevents the stomach from digesting itself?

A: Mucus lining protects the stomach wall from acid.

Q: What is peristalsis important for?

A: Moving food along the digestive tract.

Q: What type of enzyme reaction releases energy?

A: Exergonic.

Q: What macromolecules are digested in the small intestine?

A: Carbohydrates, proteins, and fats