Enzymes Flashcards
(18 cards)
How do you conduct a food test for carbohydrate (glucose)
-place a small amount of food in a boiling tube
-add one pipette full of BENEDICTS SOLUTION to the boiling tube
-place boiling tube in hot water bath for five minutes
Record observations:the solution will turn from BLUE TO BRICK RED if glucose is present
How do conduct a food test for carbohydrate (starch)
-place a piece of food in a dips on a spotting tile
-add three drops of IODINE SOLUTION
-The solution will turn from BROWN TO BLUE/BLACK if starch is present
How do you conduct a food test for protein
-place a piece of food in a boiling tube
-add a few drops of BIURETS SOLUTION
-the solution will turn from blue to purple if protein is present
How do you conduct a food test for lipids (fats and oils)
-place a piece of food in a boiling tube
-add 1cm3 of ETHANOL
-shake tube gently
-add 5cm3 of water and shake again
-if mixture becomes a cloudy white emulsion lipids are present
What are enzymes
Proteins which act as biological catalysts in metabolic reactions. This means they speed up the rate of reaction in living organisms
How does cold temperature change affect enzyme function and the active site
-at low temperatures enzyme controlled reactions are very slow as the molecules have less kinetic energy. This means there are fewer successful collisions between enzyme active suite and substrate
How does optimum temperature affect enzyme function and active site
-this is where the rate of reaction is fastest. As temp rises so does kinetic energy of enzyme meaning more successful collisions
How does hot temperature affect enzyme function and active site
-above optimum temperature the enzymes active site changes shape so the substrates fit less easily. The rate of reaction decreases
-if temperature keeps increasing the rate of reaction reaches 0% and the enzyme has denatured and the substrate can no longer fit in the active site
How is enzyme function affected by PH
-every enzyme has a optimum PH which is where the rate of reaction is fastest
-the mouth (amalayse) has a neutral PH (around 7)
-the stomach (protease) has a acidic PH (around 2)
-the small intestine (lipase) has a slightly alkaline PH (around 8)
What is the structure of the human alimentary canal
-mouth, oesophagus, stomach, small intestine (duodenum and ileum), large intestine (colon and rectum)
Define peristalsis
-peristalsis is a wave of muscular contraction that pushes food along the alimentary canal
What happens in the mouth of the digestive system
Chemical digestion occurs when the enzyme amylase in the saliva breaks down starch into maltose
What happens in the stomach of the digestive system
The stomach wall secretes hydrochloride acid which provides the optimum PH for pepsin
A protease enzyme called pepsin breaks down protein into amino acids
What happens in the duodenum (small intestine) of the digestive system
-the enzyme lipide is the procured in the pancreas and break down lipids into fatty acids and glycerol
What is bile and where is it stored
Bile is made in the liver and its function is to emulsify large lipids and is alkali to neutralise the food covered in stomach acid. It is stored in the gall bladder
How is the small intestine adapted for absorption
This lining of the ileum has a very large surface area which means it can quickly and efficiently absorb the soluble products of digestion into the blood. The large surface area is due to tiny projection from the lining called villi. Each villus contains a network of capillaries and area about 1-2 mm long but there are millions of them.
What does CORMMSS stand for
C-conditions
O-organism
R-repeat for reliability
M- measurement 1 (dependant)
M- measurement 2 (dependant)
S-special conditions 1 (control)
S- special conditions 2 (control)
How do you calculate percentage change
Percentage change=
final value-initial value/initial value x100
