The human digestive system Flashcards
(25 cards)
What are enzymes made of
‘the nature of enzymes’
Enzymes are proteins made out of polymers of amino acids
What are enzymes
define an ezyme
Enzymes are biological catalysts which increase the rate of chemical reations
Explain the enzyme ‘lock and key’ theory
The enzyme is the lock and the substrate is the key.
The enzyme has a uniquely shaped active site- shape of active site and the specific substrate are complimentary to each other like a lock and key.
The substrate will bind to the active site to form the enzyme/substrate complex.
Then a chemical reaction occurs and the enzyme breaks the substrate down to produce smaller molecules.
Name the three different enzymes
Amylase
Lipase
Protease
Name the sites in the body where amylase is produced
- Salivary glands
- Pancreas
- Small intestine
Name the sites in the body where lipase is produced
- Small intestine
- Pancreas
Name the sites in the body where protease is produced
-
Stomach
2.Small intestine - Pancreas
What is the function of amylase?
Breaks down starch into simple sugars
What is the function of the lipase enzyme
Breaks down fats (lipids) into fatty acids and glycerol
What is the function of the protease enzyme?
Breaks down proteins into amino acids
Where is bile produced?
Bile is produced in the liver (stored in the gall bladder)
Where is bile stored
Bile is stored in the gall bladder
Name the two funtions of bile
Neutralises stomach acid
Emulisifes fats
Describe how bile neutralises stomach acid
- The stomach has a slightly acidic pH as it produces hydrochloric acid, this means that when the food travels to the small intestines, it is acidic.
- The bile travels from the gall bladder to the top of the small intestines
- The bile is alkeline, so it neutralises the acid so that the enzymes can work at their optimum pH in the small intestines.
Describe how bile emulisifies lipids
Bile emulsifies lipids (fats) by breaking them down into smaller fat droplets
This increases the surface area of the fats so that the lipase enzyme can break down fats into fatty acids and glycerol at a faster rate.
What solution is used to test for reduced sugars?
Benedicts solution
Suggest why a Benedict’s solution will not work for sugars like sucrose?
Becuase sucrose is a non-reduced sugar (as opposed to a reduced sugar for which the test works)
How does temperature affect enzyme activity?
As the temperature increases, the activity of the enzyme increases
Because the increased temperature causes the enzyme and the specific substrate to have an increased kintetic energy and move faster, which increases the frequency of collisions between the substrate and the active site
What is the optimum temperature for an enzyme?
The temperature at which the enzymes are working at the fastest possible rate
So there is the maximum freuquency of successful collisions between the substrate and the active site
What happens to an enzyme when the temperature is increased aboved optimum temperature?
The enzyme becomes denatured
This changes the shape of the active site, so the specific substrate will not be able to bind into it anymore
What is meant by the optimum pH for an enzyme?
Where the activity of the enzyme is maximum
What happens when the pH is too acidic or too alkaline for a certain enzyme?
The enzyme will become denatured
All enzymes have their own specific optimum pH’s
TRUE or FALSE?
True
In which site in the body might an enzymes specific optimum pH be acidic?
And which enzyme?
In the stomach (because it is acidic here)
Protease
