CELLULAR RESPIRATION Flashcards
ATP definiton and functionr
- Adenosine Triphosphate
- is an energy carrier
- controlled release of energy
The cell needs energy for:
Mechanical work
- motor proteins
To make new materials
- for growth and replacement
For transport
- transport of molecules across membrane - conc gradient
To maintain order
- having organelles in order requires energy
The conversion of chemical energy:
C6H12O6 ———> 6CO2 + 6H20 + Energy
CO2 molecules are…
Low energy
How many mitochondria per cell
1-1000s per cell (depends on energy demand)
- muscle cell needs a lot of mitochondria - a less active cell wont
How long is a mitochnediria
1- 10 micrometers
Structure of the mitochondrion
- Contains mitochondrial DNA and ribosomes (produces some but not all mitochondrial proteins)
- Has two membranes:
- inner and outer mitochondrial membrane
- inner membrane highly folded
- inter membrane space
- mitochondrial matrix inside the inner memebrane
Cellular respiration: stage 1 glycolysis
- occurs in the cytosol
Glucose is split into 2, 3 carbon pyruvate molecule which produces 2ATP (energy carrier)
- Electrons are transferred to the high energy electron carrier - NAD+ making NADH
(Atp is produced through substrate level phosphorylation)
Cellular respiration: stage 2 - pyruvate oxidation and citric acid cycle
- in the matrix
Pyruvate is oxidised and converted into 2 Acetyl CoA releasing:
- CO2
- 2 NADH
Acetyl CoA enters the citric acid cycle
(Co2 is produced during citric acid cycle)
Output is energy Carrie ATP and high energy electron carriers NADH and FADH2
(Atp is produced through substrate level phosphorylation)
Two parts of stage 3: Oxidative phosphorylation
- Electron transport chain
-electrons from NADH and FADH2 - Chemiosmosis
-ATP production
- stage 3 involves getting the electrons back from energy carrying molecules and putting them down the electron transport chain- inner membrane proteins accept electrons
- ATP can be stored in a protein gradient in the membrane
Make-up of the inner mitochondrial membrane
inner membrane is highly folded (critstae)
- allows space for protein complexes to sit
Inter membrane space
- build a proton gradient - store energy and make ATP
The electron transport chain
- Electron carriers (NADH and FADH2) shuttle high energy electrons to the inner mitochondrial membrane
- These high energy electrons move through protein complexes embedded in the inner membrane
- As the electrons move (H+) are pumped across the membrane (and elections lose energy as the energy is now stored in the protein gradient)
What happens to the electrons after the transport chain?
- they go to oxygen to make water
- if there is no oxygen respiration can not occur as the electrons can’t leave the transport chain
How is a proton gradient in oxidative phosporlation in cellular respiration generated in cellular respiration ?
- Protons (H+) accumulate in the inter membrane space
- Making the proton concentration on either side of the inner mitochondrial membrane
- The compartments of the mitochondrion are essential for this to happen
Oxidative phosporlation - cellular respiration: CHEMIOSMOSIS
- The inner mitochondrial membrane contains the protein complex: ATP synthase
- the complex spans the memebrane from the inter membrane space to the mitochondrial matrix
- the proton gradient across the inner membrane powers atp synthesis (protons move through ATP synthase and it catalyses the production of ATP)
