Human Nutrition Flashcards
What are the biological food molecules?
Protein, Carbohydrate and Lipids
What are the chemicals present in Carbohydrates
Carbon, Hydrogen and Oxygen
What carbohydrates are monomers
The simple sugars such as glucose and fructose
What carbohydrates are polymers
Glycogen and Starch (can be broken down into smaller molecules by enzymes in mout and small intestine)
What are proteins made up of?
Long chains of amino acids. A protein is a polymer, a amino acid is a monomer
What are amino acids made up of (proteins)
Carbon, Hydrogen, Oxygen, Nitrogen
What are the chemicals present in Lipids?
Carbon, Hydrogen and Oxygen
REMEMBER: lipids are not polymers
What enzyme breaks down starch (carbs)?
Amylase into maltose (smaller sugars)
Where Amylase made?
Salivary Glands, Pancreas and Small Intestine
What enzyme breaks down proteins?
Protease into amino acids
Where is protease made?
Stomach (called pepsin), Pancreas and the small intestine
What enzyme breaks down lipids?
Lipases, into glycerol and fatty acids
Where is Lipase made?
In the pancreas and small intestine
What is bile?
It speeds up the process of digesting lipids (not an enzyme) and is released from the gal bladder
How does bile help digestion?
It emulsifies the lipids which increases surface area for the lipase enzymes to break them down
What is the role of an enzyme?
They are biological catalysts that increase the rate of chemical reaction without being used up
How does temperature effect enzyme activity?
At low temperatures the rate of reaction is low because few enzyme-substrate complexes are formed as the enzyme and substrate molecules are moving around so slowly that they rarely collide.
At higher temperatures, the rate of reaction is much higher as enzyme-substrate complexes are formed as the enzyme and substrate molecules are moving around so quickly that they collide more often.
Above the optimum however, high temperatures cause enzymes to denature meaning the active site will change shape and if this happens the substrate cannot bind to the active site.
Practical: investigate enzyme activity and change of temp
Test tube of Starch solution is placed in Water bath of set temperature for several minutes (0, 10, 20, 30, 40, 50, 60°C)
Solution of Amylase enzyme is added into test tube of Starch solution
Immediately after Amylase is added into test tube, pipette is used to add droplets of mixture into wells
Immediately after mixture is added into wells, a few drops of Iodine solution is added
Process is repeated in increments of fixed time (seconds) until Iodine turns orange, indicating that Starch has completely broken down into Glucose
Time taken for Starch to be completely broken down is compared to that of each respective temperature (time taken for Iodine solution to turn orange with each respective temperature)
Practical: investigate enzyme activity and change of pH
Add a drop of iodine to each of the wells of a spotting tile
Use a syringe to place 2 cm3 of amylase into a test tube
Add 1cm3 of buffer solution (at pH 2) to the test tube using a syringe
Use another test tube to add 2 cm3 of starch solution to the amylase and buffer solution, start the stopwatch whilst mixing using a pipette
Every 10 seconds, transfer a droplet of the solution to a new well of iodine solution (which should turn blue-black)
Repeat this transfer process every 10 seconds until the iodine solution stops turning blue-black (this means the amylase has broken down all the starch)
Record the time taken for the reaction to be completed
Repeat the investigation with buffers at different pH values (ranging from pH 3.0 to pH 7.0)
How does temperature effect enzyme activity?
Further away from optimum temp, active site denatures
