Harvesting Chemical Energy Flashcards
Does the Mitochonrion produce ATP
Yes
ATP powers cellular work – it is our energy currency
Does the hydrolysis of ATP to ADP and inorganic phosphate release energy?
Yes
In ADP where does the lost 3rd phospahte go?
It is transferred to another molecule
WHat is the ATP cycle?
the transfer of energy between complex and simple molecules in the body, with ATP as the mediator
Fuel is needed to generate ATP, what are our fuels?
Carbohydrates:
broken down to simple sugars
* Proteins:
broken down to amino acids
* Fats:
broken down to simple fats
Which are then absorbed
Many cellular processes require energy in the form of ATP is this spontaenous?
Not spontaneous
eg. cillia beating
What is the ATP cycle format?
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
The fate of glucose
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
What is cellular respiration?
the controlled release of energy from organic compounds to produce ATP
Conversion of glucose to ATP requires what 4 steps?
- Glycolysis
- Pyruvate oxidation
- Citric acid cycle (or Krebs cycle)
- Electron transport chain
C6H12O6* +6O2^ -> 6CO2* + 6H2O^ +Energy
- is oxidised
^ is reduced
Where does Glycolysis occur & does it require oxygen?
In cytosol
No oxygen required
What is the input of glycolysis & output?
input- glucose
output- 2 pyruvic acid
2 ATP & 2NADH (electron carrier in transport chain)
Where does Pyruvate oxidation occur & is oxygen required?
Mitochondrial Matrix
Oxygen is required
What is the input of Pyruvate oxidation & output?
Input - Pyruvate
Output- Acetyl CoA
no ATP, but produces 1 NADH per pyruvate (or 2 per glucose) plus 1 CO 2
WHich out of the 4 steps does not produce ATP?
Pyruvate Oxidation?
Which of the 4 steps does not require oxygen?
Glycolysis
Where does the Citric Acid Cycle occur & does it require oxygen?
Mitochinrial Matrix
Requires oxygen
Citric Acid Cycle input & output?
Input- Acetyl CoA
Output- 2 ATP
6 NADH
2 FADH2
4 CO2
(per glucose molecule)
What are the electron donors in the electron transport chain?
NADH & FADH2
What is Substrate phosphorylation?
ATP is generated by direct transfer from a substrate of a phosphate group to ADP
Out of the 4 steps which 2 make ATP thought substrate phosphorylation?
Glycolysis & Citric ACid Cycle
What is Oxidative phosphorylation?
ATP is generated from the oxidation of NADH and FADH2 and the
subsequent transfer of electrons and pumping of protons
Where does the Electron Transport Chain occur & does it require oxygen?
Inner membrane at proteins
requires oxygen
What occurs in this electro transport chain?
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
What occurs in step 4 during chemiomosis?
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
How much ATP is produced in chemiomosis
production of 26 or 28 ATP (per glucose)
ETC and chemiosmosi results in which phosphorylation?
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
What is the final electron acceptor?
Oxygen
cyanide blocks passage of electrons to O 2 =death of cell
How many ATPS are generated
10 million ATPs produced per second in one cell via cellular respiration!
Cellular respiration is versatile meaning?
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
WHat controls cellular respiration as a gate keeper?
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
What is homeostasis
the maintenance of relatively constant conditions within physiologically tolerable limits
What is insulin?
Produced by beta cells of Islets of Langerhans in pancreas
* Function: promote glucose uptake into cells (for ATP production or storage in liver)
What is glucagon?
Produced by alpha cells of Islets of Langerhans in pancreas
* Function: Stimulates the breakdown of glycogen to increase blood sugar levels
What happens if you lose the function of insulin?
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
Type 1 or insulin-dependent diabetes:
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
Type 2 or non-insulin-dependent diabetes:
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
Contradictory symptoms?
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?
