Metabolism Flashcards
1
Q
Metabolism
A
“The whole range of biochemical processes that occur within a living organism.”
2
Q
Functions of metabolism
A
- providing energy for cells via high energy electrons with a negative redox potential
- providing reductive power for anabolic processes via high energy electrons
- providing carbon to build cellular components
3
Q
Where does all energy come from?
A
the sun
- the gas in plasma formed in the sun goes through fusion, creating energy for plants
- this allows for plants to synthesise macromolecules including glucose and oxygen (photosynthesis)
- catabolic reaction
- macromolecules oxidised to produce ATP
- ATP can then drive biosynthetic reactions
- as long as there is oxygen in the sun, the energy transfer is continuous
4
Q
What is this energy used for?
A
- With energy from the sun, plants can synthesise macromolecules
- This is an example of a catabolic pathway, in which the macromolecules are oxidised to produce ATP
- This ATP can then go on to drive biosynthetic reactions
5
Q
Which two types of reactions make up metabolism?
A
Catabolism and anabolism
6
Q
Catabolism
A
- Large complex organic molecules are broken down into smaller molecules
- Degradative
- Oxidative (mostly oxygen is lost)
- Energy released (ATP)
- there is energy bonds being broken and so there must be energy being liberated
- Converging (all protein and fat is made into carbon dioxide)
7
Q
Anabolism
A
- Small molecules are constructed to for larger complex organic molecules
- disordered to ordered
- Biosynthetic
- Reductive
- Requires energy
- Diverging
8
Q
Oxidation - reduction reactions
A
- redox (electrons are transferred from one molecule to another)
- OIL RIG (Oxidation is loss, reduction is gain)
- As one molecule is oxidised (loses an electron), another is reduced (gains an electron) and so are called a ‘redox pair’
- reduced compound is called a reducing agent because it causes the reduction of compound B
- oxidised compound is called oxidising agent as it causes oxidation of compound A
- oxidised compound becomes reduced
- reduced compound becomes oxidised
9
Q
Most reduced state of carbon
A
Methane
10
Q
Most oxidised state of carbon
A
Carbon Dioxide
11
Q
The steps of glucose oxidation
A
- change in free energy, if this decreases then will become oxidised and energy will be released
- The activation energy is reduced so that the reaction can occur at the optimum temperature of 37° C
- The released free energy is reduced – this can be coupled to endergonic reactions and does not damage the cell
- Convenient control points are provided
- Can be integrated with other cellular metabolism
- the first few stages the energy is increased, decreasing the stability of the bonds
12
Q
Electron flow in chemotrophs
A
- chemotrophs obtain the energy of other cells
- Organic compounds, such as carbohydrates, amino acids and lipids, are oxidised to release high energy electrons
- Organic cofactors act as electron carriers
- NAD+ + 2H+ is reduced to NADH + H+
- FAD + 2H+ is reduced to FADH2
- A terminal electron acceptor is reduced aerobically: O2 → H2O
- the electron acceptor is oxygen which is reduced to water
13
Q
Enzymes
A
- Proteins
- Biological catalysts that facilitate the conversion of a substrate into a product
- Often require co-enzymes, e.g. ATP
- Are present in most chemical reactions in cells
- The name of an enzyme is derived from its substrate and its action: substrate action-ase
14
Q
Oxidoreductase
A
- all enzymes catalysing oxido-reductions
- e.g. alcohol dehydrogenase
15
Q
Transferases
A
- transfer a group onto a substrate
- e.g. UMP kinase
