Harvesting Chemical Energy

Question 1

Does the Mitochonrion produce ATP

Answer 1

Yes
ATP powers cellular work – it is our energy currency

Question 2

Does the hydrolysis of ATP to ADP and inorganic phosphate release energy?

Answer 2

Yes

Question 3

In ADP where does the lost 3rd phospahte go?

Answer 3

It is transferred to another molecule

Question 4

WHat is the ATP cycle?

Answer 4

the transfer of energy between complex and simple molecules in the body, with ATP as the mediator

Question 5

Fuel is needed to generate ATP, what are our fuels?

Answer 5

Carbohydrates:
broken down to simple sugars
* Proteins:
broken down to amino acids
* Fats:
broken down to simple fats
Which are then absorbed

Question 6

Many cellular processes require energy in the form of ATP is this spontaenous?

Answer 6

Not spontaneous
eg. cillia beating

Question 7

What is the ATP cycle format?

Answer 7

Complex molecules such as glycogen, proteins & triglycerides undergo-> Catabolic reactions transfer energy from complex molecules to ATP-> heat is released &/or->Simple molecules such as glucose, amino acids , glycerol & fatty acids -> undergo anabolic reactions transfer energy from ATP to complex molecules -> heat energy released or the cycle repeats

Question 8

The fate of glucose

Answer 8

Glucose in food/intestines-> glucose in bloodstream->faciliated by insulin to enter cell-> either undergoes cellular respiration ->(cellular work)
OR -> storage for harder times (glucose cross-linked
together, called glycogen,
in liver and skeletal muscle)-? faciliated by glucagon eneters blood stream again

Question 9

What is cellular respiration?

Answer 9

the controlled release of energy from organic compounds to produce ATP

Question 10

Conversion of glucose to ATP requires what 4 steps?

Answer 10

1. Glycolysis
2. Pyruvate oxidation
3. Citric acid cycle (or Krebs cycle)
4. Electron transport chain

C6H12O6* +6O2^ -> 6CO2* + 6H2O^ +Energy

• is oxidised
  ^ is reduced

Question 11

Where does Glycolysis occur & does it require oxygen?

Answer 11

In cytosol

No oxygen required

Question 12

What is the input of glycolysis & output?

Answer 12

input- glucose
output- 2 pyruvic acid
2 ATP & 2NADH (electron carrier in transport chain)

Question 13

Where does Pyruvate oxidation occur & is oxygen required?

Answer 13

Mitochondrial Matrix

Oxygen is required

Question 14

What is the input of Pyruvate oxidation & output?

Answer 14

Input - Pyruvate
Output- Acetyl CoA
no ATP, but produces 1 NADH per pyruvate (or 2 per glucose) plus 1 CO 2

Question 15

WHich out of the 4 steps does not produce ATP?

Answer 15

Pyruvate Oxidation?

Question 16

Which of the 4 steps does not require oxygen?

Answer 16

Glycolysis

Question 17

Where does the Citric Acid Cycle occur & does it require oxygen?

Answer 17

Mitochinrial Matrix
Requires oxygen

Question 18

Citric Acid Cycle input & output?

Answer 18

Input- Acetyl CoA
Output- 2 ATP
6 NADH
2 FADH2
4 CO2
(per glucose molecule)

Question 19

What are the electron donors in the electron transport chain?

Answer 19

NADH & FADH2

Question 20

What is Substrate phosphorylation?

Answer 20

ATP is generated by direct transfer from a substrate of a phosphate group to ADP

Question 21

Out of the 4 steps which 2 make ATP thought substrate phosphorylation?

Answer 21

Glycolysis & Citric ACid Cycle

Question 22

What is Oxidative phosphorylation?

Answer 22

ATP is generated from the oxidation of NADH and FADH2 and the
subsequent transfer of electrons and pumping of protons

Question 23

Where does the Electron Transport Chain occur & does it require oxygen?

Answer 23

Inner membrane at proteins
requires oxygen

Question 24

What occurs in this electro transport chain?

Answer 24

NADH and FADH 2 are oxidized to donate electron (from glycolysis & citric acid cycle)

Electrons transfer from protein-to-protein along the chain
in a series of redox reactions
At each transfer, each electron gives up a small amount of
energy which enables H+ ions to be pumped into the
intermembrane space

Oxygen “pulls” the electrons down the chain, and is then
the final electron acceptor where it is reduced to water

Question 25

What occurs in step 4 during chemiomosis?

Answer 25

The hydrogen ions in the intermembrane space rush down their
concentration gradient (chemiosmosis) through ATP synthase.
This causes the “turbine” within ATP synthase to turn
The rotation of the ATP synthase turbine enables the phosphorylation
of ADP to generate ATP

Question 26

How much ATP is produced in chemiomosis

Answer 26

production of 26 or 28 ATP (per glucose)

Question 27

ETC and chemiosmosi results in which phosphorylation?

Answer 27

Oxidative

This is much more efficient than substrate phosphorylation

the bulk of ATP production occurs here

“fall” of electrons down the chain enables
movement of H+ ions into intermembrane
space and generates a proton gradient
which “drives” the ATP synthase turbine

Question 28

What is the final electron acceptor?

Answer 28

Oxygen

cyanide blocks passage of electrons to O 2 =death of cell

Question 29

How many ATPS are generated

Answer 29

10 million ATPs produced per second in one cell via cellular respiration!

Question 30

Cellular respiration is versatile meaning?

Answer 30

We can derive energy from more than just glucose
Fats, proteins and more complex carbohydrates
generate ATP also
Monomers enter glycolysis and the citric acid
cycle at different points

Question 31

WHat controls cellular respiration as a gate keeper?

Answer 31

Phosphofructokinase is the “gate-keeper” for glycolysis; it
catalyses step 3 – where glucolysis becomes irreversable

inhibited by citrate and ATP
ie. products of cellular respiration

stimulated by AMP
AMP accumulates when ATP is being used rapidly

Question 32

What is homeostasis

Answer 32

the maintenance of relatively constant conditions within physiologically tolerable limits

Question 33

What is insulin?

Answer 33

Produced by beta cells of Islets of Langerhans in pancreas
* Function: promote glucose uptake into cells (for ATP production or storage in liver)

Question 34

What is glucagon?

Answer 34

Produced by alpha cells of Islets of Langerhans in pancreas
* Function: Stimulates the breakdown of glycogen to increase blood sugar levels

Question 35

What happens if you lose the function of insulin?

Answer 35

No glucose in cells
* No ATP from glucose
* No glycogen stored for harder times

Diabetes Mellitus :
the ability to produce or respond to
the hormone insulin is impaired
results in abnormal metabolism of
carbohydrates and elevated levels of
glucose in the blood

Question 36

Type 1 or insulin-dependent diabetes:

Answer 36

Body does not produce insulin, as beta cells of pancreas are destroyed, often this is autoimmune,
or genetic or through environmental factors
* Affects 5 – 10 % of diabetics, and onset usually occurs in children or adolescents.
* Requires insulin replacement

Question 37

Type 2 or non-insulin-dependent diabetes:

Answer 37

Body produces insulin, but receptors are non functional (insulin resistance)
* Most (>90%) diabetics are Type II, usually adults over the age of 40
* Can be linked to other pathologies and obesity

Question 38

Contradictory symptoms?

Answer 38

Diabetes mellitus is caused by a lack of functional insulin.
*As a result, levels of glucose in the blood build up, well beyond normal
homeostatic limits.
*Increased blood glucose alters the volume and osmolarity of blood, with
subsequent pathological consequences.
Two of the symptoms of this disease are:
* significantly increased hunger
* significant weight loss

These two symptoms seem to be in opposition to each other:
if the patient is constantly hungry and eating, why would they then lose weight?