Lecture 11

Question 1

What are the three types of cellular work?

Answer 1

Chemical: Synthesis of monomers
Transport: pumping of substances across bilayer
Mechanical: beating of cilia, contraction of muscles

Question 2

How does ATP power cell?

Answer 2

ATP powers cellular work by coupling exergonic reactions to endergonic

Question 3

What is an exergonic reaction?

Answer 3

releases energy

Question 4

What is a endergonic reaction?

Answer 4

absorbs energy

Question 5

How is ATP broken down during hydrolysis?

Answer 5

A phosphate bond is broken by the addition of water, a phosphate leaves the ATP which becomes ADP, energy is released

Question 6

Is ATP hydrolysis a exergonic reaction?

Answer 6

Yes as energy is released. The energy released is used to drive endergonic chemical reactions

Question 7

How is coupling achieved btw exergonic & endogenic reactions?

Answer 7

Through the transfer of a phosphate group form ATP to another molecule who is now called a phosphorylated intermediate.

Question 8

Endergonic reactions involve phosphorylation as they:

Answer 8

involves the transfer of a phosphate group from ATP to another molecule who now possess’s the phosphate group.

Question 9

Describe how the phosphorylated intermediate affects transport? (

Answer 9

Phosphate groups binds to protein & changes the proteins shape allowing the active transport of molecules through the membrane - transport pumps need energy

Question 10

Describe how the phosphorylated intermediate affects mechanical work?

Answer 10

Phosphate group binds to motor protein causing it to move down microfilament

Question 11

What occurs during a redox reaction?

Answer 11

The transfer of electrons - Oxidation & reduction

Question 12

How is NAD+ reduced to NADH?

Answer 12

A dehydrogenase enzyme removes 2 H atoms from glucose & transfers the 2electrons & 1 H+ to NAD+ forming NADH the other H+ is released

Question 13

What is NADH’s role in energy transfer within cell?

Answer 13

It brings electrons & H+ to the electron transport chain. It brings electrons to membrane carrier proteins, the movement of electrons cause H+ to diffuse through the membrane

Question 14

How is the proton motive force created?

Answer 14

Electron lose energy while moving down chain, more H+ diffuse increasing proton gradient

Question 15

The proton motive force allows:

Answer 15

ATP to be synthesised as H+ diffuse back into matrix through ATP synthase

Question 16

How is energy generated from H+ moving through ATP synthase (rotor protein)

Answer 16

H+ ions flow into ATP synthase
H+ binds to rotor causing it to change shape
This change causes the rotor to spin
Spin movement catalyse ATP production from ADP