6A- Aerobic Cellular Respiration

Question 1

what is the cytosol

Answer 1

aqueous fluid that surrounds a cell’s organelles inside the plasma membrane

Question 2

what is the mitochondrial matrix

Answer 2

the space inside the inner membrane of a mitochondrion. The site of the Krebs Cycle.

Question 3

what is crista (plural cristae)

Answer 3

the folds of the inner membrane of a mitochondrion. The site of the electron transport chain.

Question 4

what is FADH

Answer 4

A coenzyme that acts as a proton (H+) and electron carrier in cellular respiration. FAD can cycle between its FAD and FADH2 forms, depending on the reaction it takes part in.

Question 5

what is coenzyme A

Answer 5

A large organic non-protein molecule that plays a key role in the modification of pyruvate to allow it to enter the Krebs Cycle (Also called CoA)

Question 6

what is Acetyl-CoA

Answer 6

the product of the link reaction where pyruvate is conjugated to coenzyme A, creating the primary input into the Krebs Cycle.

Question 7

what is ATP synthase

Answer 7

an enzyme responsible for the reaction ADP + Pi => ATP during the electron transport chain.

Question 8

what is the overall equation for cellular respiration

Answer 8

C6H12O6 (Glucose) + 6O2 (Oxygen) ==> 6CO2 (Carbon dioxide) + H20 (Water) + 30 or 32 ATP (Energy)

Question 9

why is cellular respiration important

Answer 9

Primary method for producing energy in the human body.
Involves breakdown of glucose which is mainly found in carbohydrates (bread, honey, potatoes).
Need to breakdown glucose into ATP, a useable form of energy for our cells

Question 10

what are the 3 stages of aerobic cellular respiration

Answer 10

Glycolysis
The Krebs cycle
The electron transport chain

Question 11

what is Glycolysis and where does it occur

Answer 11

The first stage of aerobic cellular respiration.
Glyco = sugar, lysis = breakdown => glycolysis = breakdown of sugar
Occurs in the cytosol, where glucose is broken down into two pyruvate molecules (C3H4O3), 2 ATP and 2 NADH molecules

Question 12

inputs and outputs of glycolysis

Answer 12

the inputs are:
1 glucose
2 ADP + 2 Pi
2 NAD+ + 2 H+

the outputs are:
2 pyruvate
2 ATP
2 NADH

Question 13

what is the Krebs cycle (Citric acid cycle) and where does it occur

Answer 13

The second stage of respiration. Occurs in the mitochondrial matrix.
Doesn’t use oxygen but oxygen needs to be present in the cell for the Krebs Cycle to occur.
Produces four CO2, two FADH2, 6NADH, and 2ATP for every 2 pyruvate molecules.
Generates lots of high-energy electron and proton (H+) carriers (NADH and FADH2).
Pyruvate joins with coenzyme A (CoA) to form acetyl-CoA.

Question 14

what are the inputs and outputs of the krebs cycle

Answer 14

inputs:
2 acetyl-CoA (derived from 2 pyruvate)
2 ADP + 2 Pi
6 NAD+ + 6H+
2 FAD + 4H+

Outputs:
4 carbon dioxide (CO2)
2 ATP
6 NADH
2 FADH2

Question 15

whats the electron transport chain and where does it occur

Answer 15

The third step of aerobic cellular respiration.
Occurs in the inner membrane (cristae) of the mitochondria
Energy from electrons unloaded by NADH and FADH2 to generate a proton gradient which drives significant ATP production through ATP synthase.
Where majority of ATP is produced by converting high-energy coenzymes NADH and FADH2 back to NAD+ and FAD (these are recycled in glycolysis and Krebs Cycle).
Oxygen is crucial as the last electron acceptor in the electron transport chain

Question 16

the inputs and outputs of the electron transport chain

Answer 16

inputs:
6O2 + 12H+
32 or 34 ADP + 32 or 34 Pi
10 NADH
2FADH2

outputs:
6 water
32 or 34 ATP
10 NAD+ + 10H+
2 FAD + 4 H+

Question 17

what are the key enzymes in cellular respiration

Answer 17

Pyruvate kinase: catalyses the final step in glycolysis to produce pyruvate and ATP

Citrate synthase: First enzyme in the Krebs Cycle that allows recycling of acetyl-CoA

Cytochrome c oxidase: Key enzyme complex of the electron transport chain that attaches H+ and e- to oxygen to produce water.m