Chp 4-5 Flashcards
Most of the molecules in living organisms fall into three categories:
carbohydrates, proteins and lipids
These all contain carbon and so are described as
organic molecules
Chemical elements that contain carbon
Carbohydrates
Protein
Lipids
Carbohydrates
Long chains of simple sugars
Glucose
is a simple sugar ( a monosaccharide)
When 2 glucose molecules join together
maltose is formed (a disaccharide)
When lots of glucose molecules join together starch, glycogen or cellulose can form
(a polysaccharide)
Glycogen, cellulose and starch are all made from
glucose molecules
Most fats (lipids) in the body are made up of
triglycerides
Their basic unit is (fats)
1 glycerol molecule chemically bonded to 3 fatty acid chains
Can faty acids very in size and structure
Yes
Lipids are divided into
fats (solids at room temperature) and oils (liquids at room temperature)
Proteins
Long chains of amino acids
There are about 20 different amino acids
Proteins all contain
They all contain the same basic structure but the ‘R’ group is different for each one
When amino acids are joined together
Protein is formed
The amino acids can be arranged in any order, resulting in
resulting in hundreds of thousands of different proteins
Even a small difference in the order of the amino acids results in a different protein being formed
What Are Enzymes?
Enzymes are:
Catalysts that speed up the rate of a chemical reaction without being changed or used up in the reaction
What Are Enzymes?
Enzymes are:
Catalysts that speed up the rate of a chemical reaction without being changed or used up in the reaction
Proteins
Biological catalysts
Biological because they are made in living cells
Catalysts because they speed up the rate of chemical reactions without being changed
Why are enzymes necessary
Necessary to all living organisms as they maintain reaction speeds of all metabolic reactions (all the reactions that keep an organism alive) at a rate that can sustain life
For example, if we did not produce digestive enzymes, it would take around 2 - 3 weeks to digest one meal; with enzymes, it takes around 4 hours
Investigating the Effect of Temperature on Amylase
Starch solution is heated to a set temperature
Iodine is added to wells of a spotting tile
Amylase is added to the starch solution and mixed well
Every minute, droplets of solution are added to a new well of iodine solution
This is continued until the iodine stops turning blue-black (this means there is no more starch left in the solution as the amylase has broken it all down)
Time taken for the reaction to be completed is recorded
Experiment is repeated at different temperatures
The quicker the reaction is completed, the faster the enzyme is working
Investigating the Effect of pH on Amylase
Place single drops of iodine solution in rows on the tile
Label a test tube with the pH to be tested
Use the syringe to place 2cm3 of amylase in the test tube
Add 1cm3 of buffer solution to the test tube using a syringe
Use another test tube to add 2cm3 of starch solution to the amylase and buffer solution, start the stopwatch whilst mixing using a pipette
After 10 seconds, use a pipette to place one drop of mixture on the first drop of iodine, which should turn blue-black
Wait another 10 seconds and place another drop of mixture on the second drop of iodine
Repeat every 10 seconds until iodine solution remains orange-brown
Repeat experiment at different pH values - the less time the iodine solution takes to remain orange-brown, the quicker all the starch has been digested and so the better the enzyme works at that pH
active site of the enzyme when it has denatured, or if it is a low temperature, relate it to
the amount of kinetic energy the molecules have.
