Phosphorylation and the Chemiosmotic Theory

Question 1

ATP molecules are formed:

1. directly
2. indirectly

Answer 1

indirectly

Question 2

ATP molecules are formed indirectly as the H+ ions that were pumped out of the matrix now flow back into the matrix through ___________, which drives _______________.

Answer 2

ATP synthase , ATP production

Question 3

ATP synthase is a

Answer 3

transmembrane protein

Question 4

The gradient of H+ (hydrogen) has _________ energy that is due to the ______________________ having a greater/lesser concentration of H+ ions that spontaneously flow back into the matrix.

Answer 4

potential, intermembrane space, greater,

Question 5

Who developed the chemiosmotic theory and what is it?

Answer 5

Peter Mitchell developed the chemiosmotic theory, which is an explanation of the formation of ATP by the molecular complex ATP synthase, all of which results from electrons flowing through the ETC.

Question 6

chemi =

Answer 6

chemical reactions of the ETC

Question 7

osmotic =

Answer 7

gradient

Question 8

The chemical reactions (chemi) of the ETC provide the energy to create a H+ __________ (osmotic)

Answer 8

gradient

Question 9

The higher concentration of H+ ions in the intermembrane space compared to the matrix creates a difference of what 2 things?

Answer 9

concentration and charge

Question 10

Positively charged H+ ions (protons) are more concentrated in the intermembrane space, making the space more ________ compared to the matrix.

Answer 10

positive

Question 11

Why do H+ ions in the intermembrane space spontaneously flow back into the matrix?

Answer 11

There’s a drive to move towards a more negative matrix and away from area with higher concentration of H+

Question 12

Chemiosmotic theory couples the ________________ to the ___________ and __________________

Answer 12

chemical reaction in the ETC, flow of H+, formation of ATP

Question 13

What ions in the intermembrane space are positioned to generate energy?

Answer 13

H+ ions

Question 14

When does the generation of energy happen?

Answer 14

When H+ ions flow from the intermembrane space to the matrix through a pore, or channel, in a transmembrane protein called ATP synthase.

Question 15

H+ is attracted to the matrix by the slightly more negative environment of the matrix, as well as its ___________ concentration of H+ ions.

Answer 15

lower

Question 16

Which portion of the ATP synthase spans the inner membrane ?

Answer 16

Membrane bound f0 portion

Question 17

When H+ ions move down the channel of the ATP synthase, it passes through the F0 portion that spans the inner membrane. What does the flow of H+ through this portion cause?

Answer 17

Movement of H+ ions through F0 causes F0 to physically turn like a propeller (ATP synthase is physically turning in the inner membrane), which catalyzes the formation of ATP.

Question 18

What impact does F0 have on F1

Answer 18

When F0 turns, the axel turns, and when the axel turns, the catalytic sites in F1 are activated, which converts ADP to ATP.

Question 19

Which portion of ATP synthase is stationary throughout?

Answer 19

F1 and stator

Question 20

What is within F1 that is activated and converts ADP to ATP

Answer 20

catalytic sites

Question 21

True or False: formation of ATP continually happens as long as H+ ions flow through ATP synthase.

Answer 21

True

Question 22

What is the reaction for ATP production at ATP synthase ?

Answer 22

ADP + Pi + nHIM + —-> ATP + nHM+

M= matrix (indicates direction of flow)

IM = intermembrane space

Question 23

What does the reaction highlight?

Answer 23

This reaction highlights the importance of H+ flow, while also showing ATP product.

Question 24

Metabolic diseases occur when a chemical reaction is altered due to a mutation in one _____ or _____ involved in cellular metabolism.

Answer 24

protein, enzyme

Question 25

The mutation causes an essential _______ that is needed for a particular step of the pathway to __________

Answer 25

protein, stop working correctly.

Question 26

What is a known disorder that occurs in the mitochondrion ?

Answer 26

myoclonic epilepsy ragged-red fiber disease (MERRF)

Question 27

What is MERRF?

Answer 27

a collection of several similiar disorders that occur in muscle cells, which appear deformed with a distinctive fiber appearance.

Question 28

Where is the most common mutation found ?

Answer 28

in a protein that makes tRNA in the mitochondria.

Question 29

Remember, tRNA molecules are used to do what?

Answer 29

assemble proteins at the ribosome.

Question 30

Mutant protein doesn't make tRNA properly. So, the mitochondrion cannot make necessary amounts of _____.

Answer 30

ATP

Question 31

Individuals with MERRF are most affected at what tissues?

Answer 31

tissues that need lots of ATP, such as muscle and nerve cells.

Question 32

Name two symptoms of MERRF and describe the one.

Answer 32

1. muscle twitches 2. degradation of nerve cells (nerve conditions include loss of hearing and loss of eyesight)

Question 33

what is the meaning of gradient?

Answer 33

difference in charge and chemical species concentration difference between inner membrane and matrix.

Question 34

How many ATP (catalytic) sites does F1 have for ATP to be formed at?

Answer 34

3

Question 35

If a drug or toxin inhibits F0, what does it do?

Answer 35

prevents H+ ions from flowing through ATP synthase, then ATP production pauses.

Question 36

If ETC is inhibited, what happens?

Answer 36

ATP production comes to a halt .