B3: Everything except the digestive system diagram!

Test for starch

Include colour of positive test

Add iodine to food on spotting tile

Positive for starch = iodine goes blue black

Test for glucose

include positive colour

Food in Benedict’s solution

Heat in hot water bath 3 mins

Solution goes brick red = contains sugar

Test for protein

Include pos colour

Mix food with Biuret solution

Leave 2min

If mixture goes pale purple = contains protein

Food test for lipids not in spec - don’t need to revise

This is only the food test for lipids, I still need to know about the enzymes etc involving lipids

Where is bile produced

liver

Where is bile stored

gallbladder

2 things bile does

1. Increases pH of food as it enter small intestine

2. emulsification: turns fats to small droplets (increasing their SA)

So how does bile help lipase enzymes

Bile helps lipase enzymes by emulsifying fats into smaller droplets, which increases the surface area for lipase to act upon, enhancing fat digestion. (speeds up rate of reaction)

Which 2 places are ALL enzymes produced

small intestine

pancreas

Where is hydrochloric acid and what does it do

Stomach

provides best acidic conditions for protease enzymes to break down protein

Starch → ?

enzyme?

glucose

amylase enzyme

protein → ?

with what enzyme

amino acids

protease enzyme

Fats → ?

which enzyme

fatty acids and glycerol

lipase enzyme

Amylase is produced where (3)

pancreas

small intestine

salivary glands

protease produced where (3)

pancreas

small intestine

stomach

lipase produced where

pancreas

small intestine

where is water absorbed

large intestine

where is food absorbed

small intestine

what does hydrochloric acid do

kills harmful microorganisms

provides ideal low pH for enzymes