Chapter 6Chapter 6Digestion and Human HealthDigestion and Human Health

Visualizing the Digestive Visualizing the Digestive SystemSystem

MacromoleculesMacromoleculesMacromolecule Example(s) of

subunitsMain functions Examples of

macromolecules

carbohydrates sugars (such as glucose) and polymers of glucose

energy storage sugars, starches, and glycogen

lipids glycerol and three fatty acids or glycerol and two fatty acids

energy storage and cell membranes

fats, oils, and phospholipids

proteins polymers of amino acids

transport, blood clotting, support, immunity, catalysis, and muscle action

hemoglobin, fibrin, collagen, antibodies, enzymes, actin, and myosin

nucleic acids polymers of nucleotides

transfer and expression of genetic information

DNA and RNA

Formation/Degradation of Formation/Degradation of macromoleculesmacromolecules

HYDROLYSIS (addition of water) HYDROLYSIS (addition of water) separates macromolecules such as separates macromolecules such as carbohydrates, lipids, and proteins.carbohydrates, lipids, and proteins.– Carbohydrates – into monosaccharidesCarbohydrates – into monosaccharides– Lipids – into glycerol and fatty acidsLipids – into glycerol and fatty acids– Proteins – into amino acids and peptide Proteins – into amino acids and peptide

bonds.bonds. DEHYDRATION (removal of water) forms DEHYDRATION (removal of water) forms

the subunits back into their the subunits back into their macromolecule shape.macromolecule shape.

Enzyme Structure and FunctionEnzyme Structure and FunctionEnzymes are large proteins that speed up chemical reactions

The active site is the location on the enzyme where the substrate binds and the reaction takes place with the help of a coenzyme.

Enzyme and substrate fail to bind if their shapes do not match exactly..

The enzyme itself is unaffected by the reaction.

Factors affecting Enzyme Factors affecting Enzyme ActionsActions

The rate of an enzyme-catalyzed reaction is affected by the The rate of an enzyme-catalyzed reaction is affected by the concentration of substrate and the concentration of the enzyme concentration of substrate and the concentration of the enzyme that works on it. that works on it.

In addition, any chemical or physical factor that alters the In addition, any chemical or physical factor that alters the enzyme’s three-dimensional shape—such as temperature and pHenzyme’s three-dimensional shape—such as temperature and pH—can affect the enzyme’s ability to catalyze the reaction.—can affect the enzyme’s ability to catalyze the reaction.

Digestive SystemDigestive System

Digestive TractDigestive Tract

PeristalsisPeristalsis

Villi in the Small IntestineVilli in the Small Intestine

Secretions of the Digestive TractSecretions of the Digestive TractSecretion Site of production Function

saliva mouth contributes to starch digestion via salivary amylase; lubricates the inside of the mouth to assist in swallowing

mucus mouth, stomach, small intestine, and large intestine

protects the cells lining the innermost portion of the digestive tract; lubricates food as it travels through the digestive tract

enzymes mouth, stomach, small intestine, and pancreas

promote digestion of food masses into particles small enough for absorption into the bloodstream

acid stomach promotes digestion of protein

bile liver (stored in gall bladder)

suspends fat in water, using bile salts, cholesterol, and lecithin to aid digestion of fats in small intestine

bicarbonate pancreas and small intestine

neutralizes stomach acid when it reaches the small intestine

Selected Enzymes of the Digestive SystemSelected Enzymes of the Digestive System

Enzyme Where enzyme acts/pH

Substrate (food)

digested

Products of digestion Origin of enzymes

salivary amylase mouth/7 starch, glycogen maltose (disaccharide) salivary glands

pancreatic amylase

small intestine/8 starch, glycogen maltose pancreas

carbohydrases• sucrase• maltase• lactase

small intestine/8

sucrosemaltoselactose

glucose + fructoseglucoseglucose + galactose

small intestine

Pancreatic lipase small intestine/8 lipids fatty acids and glycerol pancreas

proteases• pepsin• trypsin•chymotrypsin

stomach/1–2small intestine/8small intestine/8

proteinpeptidespeptides

peptidessmaller peptidessmaller peptides

stomachpancreaspancreas

peptidases small intestine/8 peptides smaller peptides and amino acids

pancreas and small intestine

Chemical DigestionChemical Digestion

Digestive DisordersDigestive Disorders

Making Healthy Food ChoicesMaking Healthy Food Choices

Good Nutrition + Exercise = Good Nutrition + Exercise = HealthHealth

Concept OrganizerConcept Organizer