Chp 4-5

Question 1

Most of the molecules in living organisms fall into three categories:

Answer 1

carbohydrates, proteins and lipids

Question 2

These all contain carbon and so are described as

Answer 2

organic molecules

Question 3

Chemical elements that contain carbon

Answer 3

Carbohydrates
Protein
Lipids

Question 4

Carbohydrates

Answer 4

Long chains of simple sugars

Question 5

Glucose

Answer 5

is a simple sugar ( a monosaccharide)

Question 6

When 2 glucose molecules join together

Answer 6

maltose is formed (a disaccharide)

Question 7

When lots of glucose molecules join together starch, glycogen or cellulose can form

Answer 7

(a polysaccharide)

Question 8

Glycogen, cellulose and starch are all made from

Answer 8

glucose molecules

Question 9

Most fats (lipids) in the body are made up of

Answer 9

triglycerides

Question 10

Their basic unit is (fats)

Answer 10

1 glycerol molecule chemically bonded to 3 fatty acid chains

Question 11

Can faty acids very in size and structure

Answer 11

Yes

Question 12

Lipids are divided into

Answer 12

fats (solids at room temperature) and oils (liquids at room temperature)

Question 13

Proteins

Answer 13

Long chains of amino acids
There are about 20 different amino acids

Question 14

Proteins all contain

Answer 14

They all contain the same basic structure but the ‘R’ group is different for each one

Question 15

When amino acids are joined together

Answer 15

Protein is formed

Question 16

The amino acids can be arranged in any order, resulting in

Answer 16

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

Question 17

What Are Enzymes?

Answer 17

Enzymes are:
Catalysts that speed up the rate of a chemical reaction without being changed or used up in the reaction

Question 18

What Are Enzymes?

Answer 18

Enzymes are:
Catalysts that speed up the rate of a chemical reaction without being changed or used up in the reaction
Proteins

Question 19

Biological catalysts

Answer 19

Biological because they are made in living cells
Catalysts because they speed up the rate of chemical reactions without being changed

Question 20

Why are enzymes necessary

Answer 20

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

Question 21

Investigating the Effect of Temperature on Amylase

Answer 21

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

Question 22

Investigating the Effect of pH on Amylase

Answer 22

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

Question 23

active site of the enzyme when it has denatured, or if it is a low temperature, relate it to

Answer 23

the amount of kinetic energy the molecules have.