ATP and Respiration Flashcards
What would the uncontrolled release of energy from glucose result in?
Cause an increase in temperature that would destroy the cell
How is ADP converted into ATP
By the addition of a phosphate molecule.
What kind of reaction is the formation of ATP?
Endergonic
What is the addition of phosphate to ADP called?
Phosphorylation
What are the products of hydrolysis of ATP?
ADP and Pi
What type of reaction is the hydrolysis of ATP?
Exergonic
Which enzyme catalyses the hydrolysis of ATP?
ATPase
What is respiration?
A catabolic process involving a series of enzyme-catalysed reactions in cells and break down respiratory substances, such as glucose, into smaller inorganic molecules, like water and carbon dioxide.
Why is respiration described as a catabolic process?
Complex molecules (respiratory substates) are broken down into smaller,simpler molecules.
Why do organisms need to respire?
Produces chemical energy in the form of ATP for a variety of processes e.g active transport and muscle contractions
Two types of respiration
Aerobic and Anaerobic
Define aerobic respiration
A form of cellular respiration that takes place in the presence of oxygen.
What are the 4 stages of aerobic respiration?
Glycolysis;
Link reaction;
Krebs Cycle;
Electron transport chain.
Where does glycolysis occur?
In the cytosol
Does Glycolysis require oxygen?
No
Outline the stages of glycolysis
(6C)Glucose
↓(phosphorylation)
(6C)Hexose biphosphate
↓
(3C)Triose phosphate x 2
↓(oxidation)
(3C)Pyruvate x2
What are the products of Glycolysis?
Net yield of 2 ATP;
2 molecules of reduced NAD (NADH2);
2 pyruvates
How does pyruvate from glycolysis enter the mitochondria
Active transport
Where does the link reaction occur?
Mitochondrial matrix
Outline the link reaction
(3C)Pyruvate
↓(oxidative decarboxylation) →CO2
(2C)Acetate + Coenzyme A
↓
(2C)Acetyl Coenzyme A
Where does the krebs cycle occur?
Mitochondrial matrix
What is the Krebs Cycle?
A series of oxidation-reduction reactions in the matrix of the mitochondria in which acetyl coenzyme A is oxidised, generating reduced NAD, reduced FAD, ATP and carbon dioxide
Outline the stages of the Krebs Cycle
Acetyl Coenzyme A → Coenzyme A
↘
(4C)Acid → (6C) Acid
↗ ↘
(4C)Acid (5C)Acid
↑ ↓
(4C)Acid ← (4C)Acid
How many times does the Krebs cycle take place for one molecule of glucose
2
Where does the electron transport chain occur?
Inner mitochondrial membrane
What is the electron transport chain?
A series of electron carrier proteins that transfer electrons in a chain of oxidation- reduction reaction, releasing energy
First step in the electron transport chain(ETC)
Reduced NAD and FAD deliver pairs of hydrogen atoms to the ETC.
Second step in the electron transport chain(ETC)
They are oxidised, delivering protons(H+) and high energy electrons to proton pump on the inner mitochondrial membrane.
Third step in the electron transport chain(ETC)
Reduced NAD utilises all 3 proton pumps and so 3xATP are released.
Reduced FAD utilises only 2 protons pumps and 2xATP are releases
What is the role of Oxygen in the ETC?
Acts as the final electron acceptor
Describe the role of reduced NAD and FAD in the electron transport chain
They are a source of electrons and protons.
How many NAD and FAD does the complete oxidation of one glucose molecule yield
10 reduced NAD
2 reduced FAD
Describe the role of reduced NAD and reduced FAD in the electron transport chain
They are the source of electrons and protons
Where are proton pumps and electron carriers located?
In the inner mitochondrial membrane
Where does the high concentration of H+ build up?
Inter-membrane space
Where is ATP synthetase located?
in stalked particles on the cristae
How many H+ are needed to produce 1 ATP?
2
What is the Chemiosmotic theory?
The process of moving ions(e.g protons) to the other side of a biological membrane, and as a result an electrochemical gradient is generated.
How does chemiosmosis produce ATP during aerobic respiration?
Protons flow down their concentration gradient from the intermembrane space into the mitochondrial matrix via ATP synthetase.
ATP synthetase phosphorylates ADP to form ATP as protons flow through it.
What is Oxidative phosphorylation?
the process where energy is harnessed through a series of protein complexes embedded in the inner-membrane of mitochondria (called the electron transport chain and chemiosmosis) to create ATP.
Basically, it’s just the ETC + chemiosmosis.
How many ATP are produced from the oxidation of reduced NAD in aerobic respiration?
3 ATP
How many ATP are produced from the oxidation of reduced NAD in aerobic respiration?
2 ATP
Define Anaerobic Respiration
A form of cellular respiration that takes place in the absence of oxygen
Which of the 4 respiratory reactions occur during anaerobic respiration?
Glycolysis (i.e substrate level phosphorylation)
Why does glycolysis occur during anaerobic respiration
It doesn’t require oxygen to produce ATP
Why do the other 3 reactions not take place during anaerobic respiration?
The reduced Nad and FAD cannot be re-oxidised, so they are not made available to pick up more hydrogen.
2 types of Anaerobic Respiration
Fermentation;
Lactic acid formation
Outline process of Fermentation
Glucose
2xNADH/H+ ← ↓→2xATP
↓ 2x Pyruvate
2xNAD ←↓ ↓→2xCO2
↓ 2x Ethanal
2xH2 → ↓
2x Ethanol
Overall equation of Fermentation
Glucose → 2xEthanol + 2xCO2 + 2xATP
Outline process of Lactic Acid Formation
Glucose
2XH2←↓ →2xATP
2xPyruvate
2xH2→ ↓
2xLactate
Where in the body is lactic acid broken down?
Liver
What is most of the lactic acid converted into?
Glycogen
Define Oxygen Debt
The oxygen required to break down the lactate.
Total ATP yield of aerobic respiration and show your working
Process- ATP yield-
GLYCOLYSIS:
- 2 ATP(directly) → 2
- 2 NADH/H+ → 6
LINK REACTION:
- 2 NADH/H+ → 6
KREBS CYCLE:
- 2 ATP(directly) → 2
- 6 NADH/H+ → 18
- 2 FADH2 → 4
TOTAL ATP YIELD : 2+6+6+2+18+4 = 38
Name two molecules that can be used as alternative respiratory substrates
Lipids;
Proteins (during starvation only)
Explain how lipids are used in respiration
—– Glycerol → Triose phosphate → Glycolysis
↗
FAT
↘
Fatty Acids
↓
(2C)Acetate fragments
↓
Acetyl coenzyme A → Krebs Cycle
Explain how proteins are used in respiration
Glucose
—- Ammonia→Urea→Kidneys ↓
↗ Triose phosphate
Protein ↓
↘ ↱——————–> Pyruvate
Keto Acids ↓
↓ ↳———————> Acetyl CoA
↓
↳——–> Krebs Cycle
