Respiration Flashcards
Aerobic & Anaerobic respiration
Why do we need energy?
- active transport
- endocytosis
- exocytosis
- DNA replication
- movement (of cell/ within)
- cell division
- synthesis of large molecules
ATP
Adenosine triphosphate
nucleotide w/ 2 extra phosphates and an adenine nitrogenous base
Mitochondria
- matrix
- cristae
- inner membrane
- outer membrane
- intermembrane space
Aerobic Respiration
The splitting of a respiratory substrate to release CO2 (as a waste), and the reuniting of hydrogen w oxygen to release a large amount of energy.
Glycolysis
AEROBIC RESPIRATION
FIRST STAGE OF AEROBIC RESPIRATION:
Splitting of glucose to form 2x pyruvate (uses 2xATP)
IN CYTOPLASM
other products:
* 2x NADH
* (net gain) 2x ATP
NAD
Coenzyme for dehydrogenase enzymes
Phosphorylation
The addition of phosphate
The link reaction
SECOND STAGE OF RESPIRATION:
Pyruvate is decarboxylated and dehydrogenated:
IN THE MATRIX
Products:
* 2x NADH
* 2x CO2
* 2x Acetyl coenzyme A
Decarboxylation
Removal of carboxyl group from a substrate moelcule
Dehydrogenation
Removal of hydrogen atom from a substrate molecule
Substrate- level phosphorylation
Production of ATP from ADP and Pi during glycolysis and krebs cycle
The Krebs cycle
THIRD STAGE OF RESPIRATION:
Series of enzyme-catalysed reactions that oxidise acetate
Involves decarboxylation, dehhydrogenation, and substrate level phosphorylation.
IN MATRIX
Products for both cycles (one glucose):
* 6x NADH
* 4x CO2
* 2x ATP
* 2x FADH2
Oxidative Phosphorylation
LAST STAGE OF AEROBIC RESPIRATION
use of ATP synthase and energy derived from H+ gradient to make ATP
IN THE INNER MITOCHONDRIAL MEMBRANE
Products:
* Water
* (36)ATP
Electron transport chain (ETC)
Series of protein electron transporters embedded in the inner mitochondrial membrane that shuttles electrons
Dissociation
Respiration
FIRST STAGE OF OXIDATIVE PHOSPHORYLATION (last stage of aerobic resp.)
1. Hydrogen atoms are donated by NADH and FADH2 from the **krebs cycle **
2. H atoms then splits into protons and electrons
3. The high energy electrons enter the ETC and relese energy as they move along the ETC
Chemiosmosis
DEFINITION
The movement of ions across a semipermeable membrane bound structure, down an electrochemical gradient
Chemiosmosis
PROCESS
SECOND STAGE OF OXIDATIVE PHOSPHORYLATION (last stage of aerobic resp.)
4. Released energy is used to transport H+ across the inner mito. membrane from the matrix to the intermembrane space
5. A conc. gradient of protons is established between the intermembran space and matrix
6. the protons return to the matrix via facillitated diffusion through the channel protein, ATP synthase
7. The movement of H+ down their conc. grad./ provided energy for ATP synthesis (ATP is generated0
Formation of water
THIRD STAGE OF OXIDATIVE PHOSPHORYLATION (last stage of aerobic resp.)
O2 acts as the ‘final electron acceptor’ and combines with H+ and electrons at the end of the ETC to form water.
Energy yield
Theorectical yield= 36 ATP (eukaryotes), 38 ATP (bacteria)
Actual yield=
* ~30 ATP
* Some energy used to transport NADH to mitochondria
* Some ATP used for active transport of pyruvate
* ‘leaky’ membranes to protons
Anaerobic Respiration
Respiration in the abscence of O2. This is an emergency measure for ATP production when oxygen levels are low as the oxygen can’t act as the final e- acceptor.
Glycolysis
ANAEROBIC RESPIRATION - mammals
THE ONLY STEP OF ANAEROBIC RESPIRATION
Splitting of glucose to form 2x lactate
Pyruvate is formed but a hydrogen from NADH (makes it reversible) is added which forms the lactate.
IN CYTOPLASM
Products:
* 2x lactate
* Net gain 2x ATP
What happens to lactate after its been formed?
- Can be converted to pyruvate again and then enter the krebs cycle via the link reaction.
- Can be recycled to glucose & glycogen.
- If the lactate is not removed from muscles,pH would lower, inhibiting enzyme action.
Anaerobic Respiration- Glycolysis
PLANTS/ FUNGI
THE ONLY STEP OF ANAEROBIC RESPIRATION
Splitting of glucose to form 2x ethanol
Pyruvate is formed but CO2 is removed (gas lost so non-reversible) to form ethanal. Hydrogen from NADH is added which forms the ethanol.
IN CYTOPLASM
Products:
* 2x ethanol
* Net gain 2x ATP