lab 7 digestion

organs of digestion

gastrointestinal tract & accessory organs

reactants consist of

substrate and enzyme

substrate

substance that enzyme is acting on, undergo the chemical change

enzyme

protein catalyst in rxn

reagents

chemical indicators

negative control

set up where nothing is expected to happen

emulsifier (do not chemically digest) example

bile salts

bile salts role in digestion

physically break up lipids (mechanical digestion) into small droplets which provides more surface area for lipase to break down lipids

pancreatic lipase

produced b acinar cells in pancreas, enzyme that chemically digests triglycerides into fatty acids, glycerol, and monoglycerides in the small intestines

triglycerides

1 glycerol & 3 fatty acids, when broken down by lipase the 3 fatty chains are released.

bromothymol blue

chemical pH indicator that detects lipid catabolism, because released fatty acids lower pH of solution

bromothymol blue pH >7

blue, left

bromothymol blue pH <7

yellow, right

pepsin

enzyme produced by chief cells of stomach, greatest in acidic environment, breaks down into chain peptides in stomach

biuret reagent

used to detect partly digested peptides

biuret test negative

left, clear or pale blue

biuret test positive

middle, purple

biuret test positive for shorter peptides

right, pink

amylase

enzyme produced by salivary glands and pancreas, breaks down dietary starches (polysaccharides) into simple sugars (disaccharides and monosaccharides)

lugol’s solution

detects the change in starch level overtime

lugol’s test

purple/black is positive and progressively lighter as less is present