2c Biological Molecules

Question 1

What elements are found in carbohydrates? (3)

Answer 1

• Carbon
• Hydrogen
• Oxygen

Question 2

What elements are found in proteins? (5)

Answer 2

• Carbon
• Hydrogen
• Oxygen
• Nitrogen
• Sometimes Sulphur

Question 3

What elements are found in lipids? (3)

Answer 3

• Carbon
• Hydrogen
• Oxygen

Question 4

What is the structure of a lipid? (2)

Answer 4

• 3 fatty acids

- 1 glycerol molecule

Question 5

What are oils? (2)

Answer 5

• Plant lipids

- Liquids at room temperature

Question 6

What are proteins made of? (2)

Answer 6

• Long chains of amino acids.

- There are two different amino acids.

Question 7

What are starch and glycogen made up of? (1)

Answer 7

• Simple sugars joined together

Question 8

Give two examples of proteins found in the human body. (2)

Answer 8

• Collagen and keratin found in skin and nails.
• All enzymes
• Haemoglobin

Question 9

What is the food test for starch? (2)

Answer 9

• Add iodine.

- If starch present, solution changes from brick orange to blue-black.

Question 10

What is the test for glucose? (2)

Answer 10

• Heat with water and Benedict’s solution.

- If glucose present, solution changes from blue to brick red.

Question 11

What is the test for protein? (2)

Answer 11

• Add biuret reagent.

- If protein present, solution changes from blue to pink/purple.

Question 12

What is the test for lipids/fat? (2)

Answer 12

• Add ethanol and boiling water.

- If fat present, milky white emulsion forms.

Question 13

What is the function of genes? (2)

Answer 13

• Controls the activities of the cell.

- Determines which proteins are made.

Question 14

What is an enzyme? (3)

Answer 14

• A biological catalyst
• which speeds up a reaction
• without being used up.

Question 15

Define metabolism. (1)

Answer 15

• The rate at which chemical reactions take place in the body.

Question 16

What is a substrate? (1)

Answer 16

• A molecule an enzyme acts upon.

Question 17

What is the active site? (1)

Answer 17

• The area on an enzyme where a substrate attaches.

Question 18

Describe and explain the affect of too high temperature on enzyme activity. (2)

Answer 18

• It decreases activity.

- Because the enzyme denatures and substrates can no longer fit the active site.

Question 19

Describe and explain the effect decreasing the temperature on enzyme activity. (3)

Answer 19

• It decreases activity.
• Because there is lower kinetic energy.
• and fewer collisions between enzymes and substrates.

Question 20

Why is it important we control our internal temperature? (2)

Answer 20

• Too high and the enzymes denature.

- Too low and the enzymes work too slowly.

Question 21

Describe and explain the effect of too high or too low pH on enzyme activity. (2)

Answer 21

• Decreases activity.

- Enzyme denatures and substrates can no longer fit the active site.