Cellular respiration Flashcards
ATP structure
A base binded to an adenine, a phosphate sugar, 3 phosphate groups
What is ATPase
The enzyme that catalyses the breakdown of ATP
Advantages of ATP
Instant sources of energy in the cell
Releases energy in small amounts as needed
Resynthesized
It is mobile and transports chemical energy to where it is needed in the cell
Universal energy carrier and can be used in many different chemical reactions
Uses of ATP
Muscle contraction
Control of cytoskeleton
Active transport
Photosynthesis
RNA synthesis
Protein synthesis
DNA synthesis
What are the stages of respiration
Glycolysis
Link reaction
Krebs cycle
Electron transport chain
Process of glycolysis
Glucose
2ATP - 2ADP
Unstable 6 carbon molecule
2GP
2NAD - 2NADH
4ADP - 4ATP
2 pyruvate
Where does glycolysis take place
In the cytoplasm of the cell
Pyruvate in the absence of oxygen
Pyruvate remians in the cytoplasm of the cell and is converted into (animals - lactate) or (plants - ethanol)
This produces little ATP
Glycolysis in the presence of oxygen
Pyruvate is actively transported into the matrix of the mitochondria
Entering the link reaction
Pyruvate enters the mitochondria from the cytoplasm by active transport via carrier proteins and ATP
The link reaction begins in the matrix of the mitochondria
The link reaction
Pyruvate is oxidised by enzymes to producce acetate (used) and CO2 (released - decarboxylation)
This requires the reduction of NAD to NADH
Combination with Coenzyme A to form acetyl Coenzyme A (2 carbon molecule)
Krebs cycle
2 carbon Acetyl CoA enters circular pathway from the link reaction
4 carbon oxaloacetate accepts 2C Acetyl to form 6C citrate
Citrate is then converted back into oxaloacetate through redox reactions
Products of the krebs cycle
ATP
3 NADH
1 FADH
2 CO2
What is oxidative phosphorylation
Energy being released in the presence of oxygen to allow phosphorylation of ADP
Occurs in the electron transport chain
Process of oxidative phosphorylation
Reduced NAD / FAD transfer H ions / electrons along an electron transport chain (from carrier to carrier) by a series of redox reactions
These reactions are driven by oxygen as the terminal acceptor of electrons
H ions passed into the intermembrane space
H ions flow back through stalked particles (ATP synthase) by chemiosmosis
This energy is used to synthesise ATP from ADP and inorganic phosphate by a condensation reaction
What is anaerobic respiration
Takes place in the absence of oxygen
NADH is oxidised by fermentation (a process in which no more ATP molecules are generated)
What are the 2 types of anaerobic fermentation
Ethanol fermentation
Lactate fermentation
Ethanol fermentation
2 pyruvate
2NADH - 2NAD
2 CO2 released
2 ethanol (2C)
Lactate fermentation
2 pyruvate
2NADH - 2NAD
2 lactate (3C)
Consequences of no oxygen in anaerobic respiration
There is no final acceptor of electrons in the electron transport chain
Electron transport chain stops functioning
No more ATP is produced via oxidative phosphorylation
Reduced NAD and FAD aren’t oxidised by an electron carrier
No oxidised NAD and FAD are available for dehydrogenation in the krebs cycle
Krebs cycle stops
Anaerobic pathways
Some cells are able to oxidise the reduced NAD produced during glycolysis so it can be used for further hydrogen transport
Glycolysis can still continue and small amount of ATP are still produced
This is by fermentation
