Biology Lab - Digestion of Macromolecules

carbohydrate digestion

polysaccharides → monosaccharides

lipid digestion

triglycerides → glycerol + fatty acids

protein digestion

proteins → peptides + amino acids

pepsin

enzyme that breaks down proteins in the stomach to produce peptides and amino acids

amino acids

building blocks of proteins

oral cavity

where digestion begins (mechanical + chemical)

chyme

mixture of bolus and gastric juice in the stomach

parietal cells

stomach cells that secrete HCl

bile

substance that helps emulsify fats to increase surface area for enzymes; production occurs in the liver, storage occurs in the gallbladder

pancreatic amylase

enzyme that breaks down starch into sugars

small intestine

main site of nutrient absorption

duodenum

first part of the small intestine

jejunum

middle section of the small intestine

ileum

final section of the small intestine

large intestine

absorbs water and forms feces

cecum

beginning of large intestine (appendix attached)

colon

major part of large intestine

rectum

stores feces before elimination

anus

exit point of digestive tract

lipase

enzyme that breaks lipids into fatty acids + glycerol

phenol red

Indicates pH changes caused by breakdown of lipids into fatty acids

emulsification

breaking fat into smaller droplets

acidic solution (yellow)

indicates more lipid digestion

basic solution (red/pink)

indicates less lipids digestion

biuret reagent

turns purple in the presence of peptide bonds (protein presence)

albumin

protein from egg whites used in experiment

peptide bonds

links between amino acids in proteins

amylase

enzyme that breaks starch (carbohydrates) into maltose

maltose

disaccharide produced from starch digestion

benedicts reagent

detects reducing sugars

reducing sugars

sugars that can donate electrons (e.g., maltose)

% Transmittance (%T)

measure of light passing through solution (used to quantify sugar)

phospholipids

lipid-based molecules that form the structural framework of the cell membrane

peristalsis

wave-like muscle contractions that move food through the digestive tract

NaOH

raises pH to allow detection of pH changes

mouth

starch digestion begins here by amylase

standard curve calculation

x = y (%T) + (intercept) / (slope)

pathway of food

mouth → esophagus → stomach → duodenum → jejunum → ileum → large intestine → rectum → anus