Enzymes and Digestion Flashcards

Flashcards on Enzymes and Digestion

Enzymes

Proteins present in all living cells that act as biological catalysts, speeding up a reaction without being changed themselves.

Extracellular Enzymes

Enzymes that leave the cell and exert their action outside, such as digestive enzymes that break down food substances in our gut.

Intracellular Enzymes

Enzymes that exert their action inside the cell, speeding up and controlling chemical reactions.

Enzyme Specificity

Each enzyme controls one particular reaction or type of reaction; for example, amylases act on carbohydrates, lipases on lipids, and proteases on proteins.

Optimum pH

The specific pH at which an enzyme works best; digestive enzymes in the stomach work best in acidic conditions, while those in the small intestine work best in alkaline conditions.

Optimum Temperature

The particular temperature at which enzymes function best, generally around 37°C in the human body.

Denaturation

The process by which enzymes lose their shape and stop working, usually due to high temperatures (above 45°C) or extreme pH conditions.

Lock and Key Theory

A model explaining enzyme action where the substrate fits into the active site of the enzyme like a key fits into a lock.

Active Site

The cavity on the surface of an enzyme molecule where the substrate binds and the reaction takes place.

Anabolic Enzymes

Enzymes that help small molecules join to form bigger ones, aiding in building important molecules in cells.

Catabolic Enzymes

Enzymes that help break larger molecules into smaller ones, important in digestion where large food molecules are broken down.

Amylase

A digestive enzyme that breaks down polysaccharides (starch) into disaccharides (maltose).

Lipase

A digestive enzyme that breaks down lipids into fatty acids and glycerol.

Protease

A digestive enzyme that breaks down proteins into smaller peptide chains or amino acids.

Pepsin

A digestive enzyme found in the stomach that breaks down polypeptides into smaller peptide chains; works best at a pH of 2.

Trypsin

An enzyme produced in the pancreas that breaks down proteins and polypeptides into amino acids in the duodenum.

Saliva

A slightly acidic (pH 6-7) secretion in the mouth that dilutes and moistens food, lubricates the bolus for swallowing, and contains salivary amylase to break down starch into maltose.

Epiglottis

A flap-like cartilage that prevents food particles from entering the trachea during swallowing.

Peristalsis

Waves of muscle contraction in the esophagus that move food from the mouth to the stomach.

Gastric Juice

A secretion released by gastric glands in the stomach, containing pepsin, mucus, and hydrochloric acid to kill bacteria and activate pepsin.

Bile

A substance produced by the liver and stored in the gall bladder that emulsifies fats into smaller droplets, increasing the surface area for lipase to break them down more easily.

Pancreatic Juice

A secretion produced by the pancreas, containing pancreatic amylase, lipase, and trypsinogen, which are released into the small intestine to continue digestion.

Villi

Tiny projections on the internal surface of the ileum that increase the absorbing surface for digested food, containing blood capillaries and lacteals for absorption.

Chyme

The soup-like mixture of food and gastric juices produced in the stomach.

Bolus

A ball of solid mass of food formed by the tongue before swallowing.

Digestion

The breakdown of large insoluble food molecules into smaller soluble molecules

Assimilation

The use of the absorbed food nutrients within the living organism, a process occurring after the transport of these nutrients.

Egestion

The elimination of undigested food from the organisms.