SB1e-h

Question 1

How do bacteria get substances for energy, growth and development?

Answer 1

They release digestive enzymes into their environments and then absorb digested food into their cells.

Question 2

In humans, what do digestive enzymes do?

Answer 2

They turn the large molecules in our food into the smaller sub-units they are made of.
The digested molecules are then small enough to be absorbed by the small intestine.

Question 3

Synthesis

Answer 3

Building larger molecules from smaller sub-units.

Question 4

Polymers

Answer 4

Complex carbohydrates and proteins are examples because they are made up of many similar molecules or monomers, joined in a chain.

Question 5

Biological catalysts

Answer 5

Speed up breakdown (e.g. digestion) and synthesis reactions are enzymes.
Biological catalysts speed up the rate of reactions.

Question 6

Substrates

Answer 6

The substances that enzymes work on.

Question 7

Products

Answer 7

The substances that are produced

Question 8

Amylase

Answer 8

Found in the saliva and small intestine.
Reaction catalyzed: breaking sown starch to small sugars, such a maltose.

Question 9

Catalase

Answer 9

Found in most cells, but especially liver cells.
Reaction catalysed: breaking down hydroge nperoxide made in many cell reactions to water and oxygen.

Question 10

Starch synthase

Answer 10

Found in a plant
Reaction catalysed: synthesis of starch from glucose

Question 11

DNA polymerase

Answer 11

Found in the nucleus
Reaction catalysed: synthesis of DNA from its monomers.

Question 12

Chemical reagents

Answer 12

Used in food tests to identify changes in carbohydrates, sucrose and glucose.

Question 13

Iodine solution

Answer 13

Chemical reagent
Changes from a yellow-orange to a blue-black colour when in contact with starch.

Question 14

Reducing sugars

Answer 14

All of the smallest sugars (including glucose and fructose)

Question 15

Benedict’s solution

Answer 15

Chemical reagent
Used to test the presence of reducing sugars. Goes from a lighter blue to a bright red.

Question 16

Biuret test

Answer 16

• Potassium hydroxide is mixed with a solution if the food.
• Two drops of copper sulfate solution are then added.
• If the pale blue solution turns purple, this indicated protein in the food.

Question 17

(Ethanol) emulsion test

Answer 17

• The food is mixed with ethanol and shaken.
• Some of that mixture is then poured into water and shaken.
• Some of that mixture is then poured into water and shaken again.
• Fats and oils dissolved in the ethanol float to the surface, forming a cloudy emulsion, when the mixture is left to stand.