Week 5 Flashcards
(23 cards)
What are the mitochondria?
The main site for cellular energy generation
What is the role of the mitochondria?
Generates energy by oxidative phosphorylation, which is the process that takes place in the mitochondria
What breaks down into acetyl-CoA?
Carbohydrates, proteins, lipids
What is the role of acetyl-CoA?
To generate ATP, NADH and FADH2 in the citric acid cycle
Why are NADH and FADH2 important during the oxidative phosphorylation process?
NADH and FADH2 are important because they generate energy
Where does the citric acid cycle operate?
In the mitochondria, only under aerobic conditions
Summarise the citric acid cycle
Acetyl (2C) bonds to oxaloacetate (4C) to form citrate (6C)
Oxidation and decarboxylation converts citric to oxaloacetate
oxaloacetate bonds with another acetyl to repeat the cycle
What are the roles of the regulation of the citric acid cycle?
Low levels of ATP stimulate the formation of acetyl CoA for the citric acid cycle
High levels of ATP and NADH decrease the formation of acetyl CoA and down the citric acid cycle
What is the oxidative phosphorylation process?
A process that requires oxygen to convert ADP to ATP through the addition of a third phosphorous (known as phosphorylation)
How does the oxidative phosphorylation process occur?
AN electron chain utilises NADH and FADH2 to drive an enzyme that creates ATP
What is the role of electron carriers?
To accept hydrogen and reduced coenzymes NADH and FADH2, which then are oxidised and reduced to provide energy for the synthesis of ATP
Where is the electron transport system located?
It is attached to the inner membrane of the mitochondrion
Identify each protein complex.
Complex I: NADH dehydrogenases
Complex II: succinate dehydrogenase
Compex III: CoQ-Cytochrome c reductase
Complex IV: cytochrome c oxidase
What is the process of the chemiosmotic model?
Step 1: complexes I, III and IV pump protons into intermembrane space, creating a proton gradient
Step 2: protons must pass through ATP synthase to return to the matrix
Step 3: the flow of protons through ATP synthase, provides energy for ATP synthesis (oxidative phosphorylation): ADP + Pi + energy ———-> ATP
What occurs during ATP synthase?
Protons flow back to a matrix through the channel in F0 complex
What is the role of proton flow?
To provide energy that drives the ATP synthesis by F1 complex
What happens in the F1 complex of ATP synthase?
A centre subunit (y) is surrounded by three protein subunits: loose (L), tight (T), open (O)
Energy from protein flow through F0, turns the centre subunit (y), chain the shape (conformation) of the three subunits
- Powered by H+ and generating ATP
Whats happens during ATP synthesis?
Step 1: ADP and Pi enter loose (L) site
Step 2: the centre subunits turns to change the L site to a tight (T) conformation, forming ATP
Step 3: the centre subunit changes the T site to an open (O) site, releasing the ATP
What happens during electron transport?
The energy level decrease for electrons:
From NADH (complex I) provides energy for 3 ATP:
NADH + 3 ADP + 3 Pi ———-> NAD+ + 3 ATP
From FADH2 (complex II) provides energy for 2 ATP:
FADH2 + 2 ATP + 2 Pi ———> FAD + 2 ATP
What to the process of regulation of electron transport?
Low levels of ADP, P, oxygen, NADH decrease electron transport activity
High levels of ADP activate electron transport
ATP energy from glucose?
The complete oxidation of glucose yields: 6 CO2, 6 H2O, 36 ATP
What do glucose molecules that have undergone complete oxidation provides?
Glycolysis: 2 ATP + 2 NADH (FADH2)
2 Pyruvate: 2 NADH
2 Acetyl-CoA: 6 NADH, 2 FADH2, 2 GTP
C6H12O6 + 6 O2 + 36 ADP + 36 Pi ———–> 6 CO2 + 6 H2O + 36 ATP
Overview of energy from carbohydrates
Saccharides —-> glucose (digestion)
Glucose —-> pyruvate + ATP (glycolysis)
Pyruvate —-> acetyl-CoA + NADH (oxidation)
Acetyl-CoA —-> ATP + NADH + FADH2 (citric acid cycle)
NADH/FADH2 —-> ATP (oxidative phosphorylation)
