Chapter 12 Flashcards
What are the two different types of respiration?
Aerobic
Anaerobic
When does Aerobic respiration take place and what are the products?
Requires O2
Produces CO2 + H2O and much ATP
When does anaerobic respiration take place and what are the products?
Absence of O2
Produces: Lactate, Ethanol + CO2 + Little ATP
What are the four stages of aerobic respiration?
1) Glycolysis
2) Links Reaction
3) Krebs Cycle
4) Oxidative Phosphorylation
Summarise the process of Glycolysis
The splitting of 6-carbon molecule into two 3-pyruvate molecule
Summarise the process of Links Reaction
3-carbon pyruvate molecules enter a series of reaction which leads to the formation of acetyl-coenzyme A
Summarise the process of Krebs Cycle
Introduction of acetyl coenzyme A into a cycle of oxidation-reduction reactions that yield some ATP + Large quantity of NAD + FAD
Summarise the process of Oxidative Phosphorylation
Use of electrons, associated with Reduced NAD and FAD, released from the Krebs cycle to synthesize ATP with water produced as a by-product
Where does glycolysis occur within the cell?
Cytoplasm
State the four stages of glycolysis?
Stage 1: Phosphorylation of gluscose to glucose phosphate
Stage 2: Splitting of the phosphorylated glucose
Stage 3: Oxidation of triose phosphate
Stage 4: the production of ATP
What is the overall yield from glycolysis?
- 2 molecules of ATP
- 2 molecules of reduced NAD
- 2 Molecules of pyruvate
In what way are pyruvate molecules oxidized, Before the Krebs cycle?
Through Links Reaction
In eukaryotic cells where do the Krebs cycle and links reaction take place?
Mitochondria
matrix
What series of reactions does pyruvate go through during links reaction?
- Pyruvate is oxidized to acetate
- 2-carbon acetate combines with a Coenzyme A to produce acetyl-coenzyme A
What is the overall reaction of pyruvate during links reaction?
Pyruvate
Summarise the Krebs cycle?
- 2-carbon acetyl coenzyme combines with a 4-carbon molecule to produce ab 6-carbon molecule
- In a series of reactions the 6-carbon molecule loses CO2 + Hydrogen to give a 4-carbon molecule + a single molecule of ATP produce as a result of SUBSTRATE LEVEL PHOSPHORYLATION
- The 4-carbon molecule can now combine with a new molecule of acetyl coenzyme A to begin the cycle again
For each pyruvate what do the links reaction and Krebs cycle produce?
- Reduced Coenzymes (NAD, FAD)
- 1 molecule of ATP
- 3 molecules of CO2
Are coenzymes enzymes?
NO
What are coenzymes?
Molecules that some enzymes require in order tio function
Coenzymes play a major role in photosynthesis where they carry H atom from 1 molecule to another?
Give an example of when coenzymes carry H atom from 1 molecule to another?
- NAD (Respiration)
- FAD (Krebs Cycle)
- NADH (Photosynthesis)
Why does the Krebs cycle perform an important role in cells?
- Breaks down macromolecules into smaller ones
-Produce H atoms that are carried by NAD to electron transfer chain + provide energy for oxidative phosphorylation
leads to the production of ATP provides energy for the cell
-Regenerates 4-carbon molecule that combines with acetyle coenzyme A, which would toherwise accumulate
-Source of intermediate compounds used by cells
What coenzymes carry H atoms to oxidative phosphorylation?
NAD
FAD
What is oxidative phosphorylation?
The mechanism by which some energy of the energy electrons within H atoms is conserved in the formation of ATP
Where does oxidative phosphorylation take place?
Mitochondria
What is within the cristae that are involved in oxidative phosphorylation and hence ATP synthesis?
enzymes and other protein
The synthesis of ATP by oxidative phosphorylation involves the transfer of electrons down a series of electron carrier molecules which together form the
Electron transfer chain
Describe the process of the synthesis of ATP and oxidative phosphorylation?
- H atoms (from glycolysis + krebs cycle) combine with coenzymes NAD + FAD
- Reduced NAD and FAD donate the electrons of the H atoms they are carrying to the first molecule in the Electron Transfer Carrier
- electrons pass along a chain of ETC molecules in a series of OXIDATION-REDUCTION reactions
- As electrons flow along the chains, the energy they release causes the active transport of protons across the inner mitochondrial + inner intermembrane space
- Protons accumulate in the Intermembranal space before they diffuse back into the mitochondrial matrix through ATP synthase channels embedded in the inner mitochondrial membrane
- At the end of the chain the e- combine with these protons + o2 TO FORM H2O
- O2 is, therefore, the final acceptor of e- in the ETC
What is the theory called for the synthesis of ATP and oxidative phosphorylation?
Chemiosmotic theory of oxidative phosphorylation
What is the importance of oxygen in respiration?
Is to act as a final acceptor of the H atoms produced in glycolysis + Krebs cycle
Without it Ha atoms + electrons would ‘back up’ along the chain + the process of respiration would come to a halt
How is energy released in stages? how is it useful?
The energy released little at a time, more can be harvested for the benefit of the organism
- therefore, electrons carried by NAD and FAD are not transferred in one explosive step
- They are carried along with a series of ETC molecules each of which is slightly lower energy level
- therefore electrons move down a gradient
- Transfer of gradient allows their energy + therefore more useful
What are alternative respiratory substances?
Lipids + proteins
What must be done to the lipids before respiration?
Lipids are hydrolyzed to glycerol + fatty acids
Describe how lipids are used to be respired?
- Glycerol is then phosphorylated + converted to triose phosphate which enters the glycolysis pathway and subsequently the Krebs cycle
- Fatty acid component is broken down into 2 carbon fragments of carb + many H atoms
- H atoms are used to produce ATP during oxidative phosphorylation
Describe how proteins are used for respiration?
- Hydrolyzed to AA
- They have their amino group removed (deamination) entering the respiratory pathway at different points depending on C atoms they contain 2-c compound converted to pyruvate
- 4 and 5 carbon compounds are converted to intermediates in the Krebs Cycle
Why is it that during the absence of O2 The Krebs cycle and electron transfer chain cannot continue?
FAD and Nad will be reduced
nor will be available to take up H+ produced during K cycle + o enzymes stop working
During the absence of O2, how do you produce ATP?
Aerobic respiration is the only potential way of producing ATP
