Metabolism and Bioenergetics Flashcards
What is metabolism?
Describes all the chemical activities that support life in all cells and organisms
-enables cells to transform energy - extract/transfer chemical energy from food/light, use chemical energy to synthesise macroimolecules and perform biological work
What are chemotrophs?
Transform chemical energy as - humans
What are heterotrophs?
Need some pre-formed organic nutrients
What are phototrophs?
Transform light energy
What are autotrophs?
Synthesise all molecules from CO2 e.g plants
How do phototrophs/plants store energy?
In the form of simple sugars
How do chemotrophs get their energy?
Oxidation of the simple sugars
-electrons passed to from O2 to H20 and CO2 - uses O2 to make energy
What is anabolism?
Input energy
inorganic precursors react to form small organic molecules that are used to synthesize carbs, lipid, protein, nucleic acids
What is metabolome?
A term for all the metabolites in a cell or system
What is metabolomics?
Systemic characteristics of metabolome including under specific conditions
Catabolism vs Anabolism
Catabolism- breakdown
-convergent - releases energy - transforms fuel into cell energy e.g ATP, NADH
Anabolism- building
-divergent - require and use cell energy e.g ATP, NADH etc to synthesise diverse macromolecules from small precursor molecules
What diseases does defective metabolism cause?
diabetes, cancer, neurodegeneration, heart disease, infection, inflammation, immunological dysfunction
What is bioenergectics?
Quantitative study of energy transductions in living cells/organisms/systems
What is the thermodynamics in biology considered in terms of?
Change in Gibbs free energy - triangke G
If triangle G is negative?
Exergonic - often releases energy
-reaction occurs spontaneously
If triangle G is positive?
-reaction cant occur spontaneously
-endergonic - requires energy input
What is triangle G the same as?
K’eq - product/reactant
If K’eq is greater than 1?
Then triangle G is negative - reaction is exergonic and proceeds forward
ATP usage wit regards to catabolism and anabolism
-Catabolic pathways produce ATP
-Anabolic pathways and cellular work use ATP
ATP structure
-Adenine nucleotide contains adenine, ribose and triphosphate
-Phosphate groups strong neg charge sp repel each other
-The phosphoanhydride bond is ‘ready to be broken’
-The breaking/cleavage of this bond creates/transfers energy
Energy production in ATP
ATP is hydrolysed at phosphoanhydride bonds
-Each phosphoanhydride bond break/hydrolysis has a high neg triangle G0 energy - 30 kJ/mol
Where is ATP mostly synthesised?
in the mitochondria
Oxidative phosphorylation vs substrate level phosphorylation?
-Transfer of catabolic free energy via electron transfer propels the enzyme ATP-synthase to synthesise ATP in presence of O2 - oxidative
-Smaller amounts of ATP made directly from substrates - substrate level phosphorylation
Other energy molecules besides ATP?
Other phosphorylated compounds - phosphoenolpyruvate, phosphocreatine
Non phosphorylated compounds - thioesters
What major reaction type transforms energy in metabolism?
Oxidation/reduction
Oxidation vs Reduction
Oxidation forms basis of catabolism- giving energy
-energy provision
-growth/ respiration/ ATP production
Reduction forms basis of anabolism - using-taking energy
-cells to work, building, biomolecules synthesis
How does electron transfer take place?
By electron motive force EMF
What does G0 relate to with regards to electrons
G0 directly relates to the numnber of electrons transferred in metabnolic reaction
G0= -nFtriangleE
What are 4 ways electrons are transferred in metabolism from electron donor to electron acceptor?
1) Directly as electrons
2) As hydrogen atoms (hydrogen atom consists of 1 proton 1 electron)
3) As hydride ion (neg form of H) - has 2 electrons - NAD
4) By direct combination of organic reductants with O2
What does biological oxidations in catabolism often involve?
The removal of hydrogen atoms using dehydrogenases
What is the terminal electron acceptor?
Oxygen as it is the most electronegative
What do biological reductions in anabolism often involve?
Addition of hydrogen by hydrogenases
Why do some biomolecules release more energy than others?
-More hydrogens present
What does NAD stand for?
Nicotinamide Adenine Dinucleotide
NAD and NADP are soluble electron carriers
NAD - catabolism
NADP- anabolism
What are NAD and NADP derived from?
Vitamin niacin which is vit B3
-in tuna, salmon, halibut, vanison, asparagus
What does deficiency of niacin cause?
Pellagra in humans
-dermatitis, diarrhea, dementia
How does NAD/NADP work as electron carriers?
Nicotinamide ring accepts a hydride ion - 2 electrons and 1 proton
NAD+ or NADP+ accept a hydride ion from a reduced susbtrate
NADH or NADPH donate a hydride ion to an oxidized substrate
NAD with alcohol dehydrogenase
Ethanol is oxidised from an alcohol to an aldehyde by enzyme alcohol dehydrogenase
-alcohol dehydrogenase is in the lining of the stomach and liver - allows comsu,ptionm of alcohol
What does FAD and FMN stand for? Structure?
Flavin Adenine Dinucleotide
Flavin MonoNucleotide
-are very tightly and sometimes covalently bound to dehydrogenases called flavoproteins
-isoalloxazine ring structure accepts 1 or 2 electrons
What is FAD and FMN derived from?
Riboflavin Vit B2
-milk, cheese, beans, leafy greens
