Biological molecules

Question 2

Chemical elements make up carbohydrates

Answer 2

Carbon, hydrogen, oxygen

Question 3

Chemical elements that make up protein

Answer 3

Carbon, Hydrogen, oxygen and nitrogen

Question 4

Chemical elements that make up Lipids (fats)

Answer 4

Carbon, oxygen and hydrogen

Question 5

Carbohydrates, protein and lipids

Answer 5

They are large molecules made up from smaller basic units

Question 6

Starch and glycogen

Answer 6

simple sugar and glucose molecules

Question 7

Protein

Answer 7

Amino acids

Question 8

Lipids

Answer 8

Fatty acids and glycerol

Question 9

Food test: Glucose

Answer 9

Add Benedict’s Solution into sample solution in test tube.
Heat at 60-70 °c in water for 5 minutes
Take test tube out of water bath and observe the colour
Colour changes from blue to orange or brick red

Question 10

Food test: starch

Answer 10

We use iodine to test for the presence or absence of starch in a food sample
Add drops of iodine solution to the food sample
Colour change from orange-brown to blue-black

Question 11

Food test: Protein

Answer 11

Add drops of blutet solution to the food sample
Colour change from blue to violet/purple

Question 12

Food test: Fat (lipids)

Answer 12

food sample is mixed with 2 cm3 of ethanol and shaken
The ethanol is added to an equal volume of cold water
Cloudy emulsion forming

Question 13

Metabolism

Answer 13

The sum of all chemical reactions taking place in a cell

Question 14

Anabolic reactions

Answer 14

Energy and small molecule produces a large molecule

Question 15

Catabolic reaction

Answer 15

Large molecule produces a smaller molecule and energy

Question 16

Catalyst

Answer 16

A subatnce that changes the rate of reaction without changing the substance produced

Question 17

Enzymes

Answer 17

Are biological catalysts which control the rate of reaction that occurs inside the cell and in the whole organisms

Question 18

Substrate

Answer 18

The molecule that the enzyme acts on is the substrate

Question 19

Active site

Answer 19

The binding site that holds the substrate in place

Question 20

How enzymes work (4)

Answer 20

Substrate enter the enzyme’s active site.
Enzyme-substrate complex complex forms and reaction takes place.
Products from and drift away from the enzyme.
The enzyme is free to act on more substrate molecules.

Question 22

Factors that could affect enzyme activity

Answer 22

Temperature
pH
Enzyme concentration
Substrate concentration

Question 23

Factors affecting enzymes: temperature (3)

Answer 23

Increasing the temperature increases rate of enzyme reaction.
As the temperature increases kinetic energy of the molecules increases so they collide more often.
Due to this more enzyme/substrate complex forms. Hence more products form in a shorter period of time

Question 24

Optimum temperature

Answer 24

Temperature at which enzymes works best

Question 25

Denature (2)

Answer 25

If the temperature and pH changes sufficiently beyond an enzyme’s optimum and the shape of the enzyme irreversibly changes.
This affects the shape of the active site and means that the enzyme will no longer work.

Question 26

Factors affecting enzymes: pH

Answer 26

The pH inside the cell is neutral and most enzymes are evolved to work best at this pH.