APT, Water and Inorganic Ions

Question 1

Cells constantly hydrolyse ATP to provide energy.
Describe how ATP is resynthesised in cells. (2)

Answer 1

• from ADP and Pi
• by ATP synthase
• during respiration

Question 2

Give two ways in which hydrolysis of ATP is used in cells.

Answer 2

• to provide energy for other reactions
• to add phosphate to other substances and make them more reactive

Question 3

The scientists concluded that an increase in phosphate in the embryo was linked to growth of the embryo.

Suggest two reasons why an increase in phosphate can be linked to growth of the embryo. (2)

Answer 3

• phosphate required to make DNA
• phosphate required to make ATP

Question 4

The chilling requirement of seeds of certain plant species is considered to be an adaptation for survival in countries with seasonal changes in environmental conditions.

Suggest how this adaptation may enable these plant species to survive and respond to seasonal changes. (3)

Answer 4

• seeds remain dormant in winter so this is when growth occurs
• seeds/ plants develop in the summer
• plants photosynthesise in warmth
• produce more offspring in spring

Question 5

Describe how an ATP molecule is formed from its component molecules.(4)

Answer 5

• 3 components: adenine, ribose/ pentose, 3phosphates
• condensation reaction
• ATP synthase

Question 6

As shown in figure 1 ATP synthase has two functions.
-it catalyses the synthase of ATP
-it allows the movement of h+ ions

Suggest how the shape of ATP synthase allows it to have these two functions. Explain your answers. (4)

Answer 6

Catalyses synthase of ATP:
- active site complementary to ADP and Pi
- enzyme-substrate complex forms

Allows the movement of h+ ions:
- channel in membrane
- allows facilitates diffusion of H+ ions