Overview of Metabolism Flashcards
What is metabolism ?
A series of enzyme reaction within cells which converts fuel molecules to useful energy.
These enzyme reactions involve synthesis, breakdown and interconversion into essential biomolecules.
What is catabolism?
Ends in “lysis” ( glycolysis, lipolysis, glycolysis)
Generates ATP, NADH
Mitochondrial
What is anabolism?
Ends in “genesis” (gluconeogenesis, lipogenesis, glycogenesis)
Uses ATP, GTP,UTP
Cytosol
Describe what respiration entails?
Pathways of glycolysis and TCA acting together
Converting glucose into CO2
Through mitochondrial respiration provides energy for tissues
C6H12O6 + 6O2 ———> 6CO2 + 6H20 + 30 ATP + 2 GTP
Describe how fatty acids are transported into the cytosol?
FATTY ACIDS- diffuse into the cell by simple diffusion into the cell by diffusion across the CSM.
- can be even more specific in the sense that there can be specific carriers (albumin) - this is really good because it can be controlled
The fatty acids are then available to be stored or broken down.
Describe how glucose can be transported into the cytosol?
Glucose moves into he cell by diffusion through glucose transporters- SPECIFIC
How can electrons be transported across the cell membrane?
through electron transport chain- without it leaking
Describe ATP
Andenosine triphosphate-
chemically stable at pH 6-9
Structural features recognised by specific proteins and enzymes
Made out of ribose, adenine, 3 phosphates
Anhydride bonds have high energy
ATP —–> ADP + Pi + H+ + ENERGY
How do you use the ATP in cells?
ATP hydrolysis can shift the equilibria of a coupled reaction by factor 10^8
A + ATP + H20 —-> B +ADP + H+ + Pi
Where is ATP used?
Used directly in cell motility and contraction-
eg. with myosin and dynein
Used in metabolism to add Pi to metabolic intermediates
Glucose + ATP —> Glucose-6-phosphate + ADP
Used in Na/K+ pumps, AT transport, metabolic control
Describe metabolic pathways
Each reaction is coupled to the next reaction
Enzyme 1 is usually a control enzyme- it catalyses the reaction and it usually controls the pathway.
The rate of the biochemical reaction is dependant on enzyme activity
the direction of the reaction is dependant on these properties
How can the rate of a reaction be regulated?
- interconversion of ‘active’ and ‘inactive’ forms of the key enzymes
eg. by covalent modification-
INACTIVE ENZYME —> ACTIVE ENZYME-Pi
through ATP and protein kinase
NB the opposite is done through protein phosphatase
-Alter the availability of the substrate- increasing the transport system into the cell
-Increasing the amount of the enzyme present in the cell, by increasing the rate of transcription
( up regulation or down regulation)
-Allsoteric enzymes (those that will have an activating and inhibitory site)
Metabolic Reactions require-
fuel molecules
enzyme catalysts
Cofactors - activating ions or Coenzymes/prosthetic groups
eg. ATP for kinase enzyme
eg. UTP for synthesis of complex sugars
eg. GTP for synthesis of proteins
