Metabolism Flashcards
what are the functions of metabolism
Cells need a source of energy
This energy is provided by electrons with negative redox potential. (high energy electrons)
Cells need anabolic reductive power for anabolic processes (provided by high energy electrons)
Cells need a source of carbon to build cellular components
how do plants synthesise macromolecules
using sunlight as energy
Metabolism =?
Catabolism + Anabolism
Catabolism
Large complex organic molecules are decomposed into small molecules
It is degradative
It is oxidative
Energy is liberated
It is converging
Anabolism
Large complex organic molecules are constructed from small molecules
It is biosynthetic
It is reductive
Energy is required
It is diverging
what is referred to as a redox reaction
Oxidation-reduction reaction, this is where electrons are transferred from one molecule to another
Oxidation states of carbon
(Most reduced state with the highest free energy) alkane> alcohol> aldehyde>carboxylic acid> carbon dioxide> (final product or catabolism)
glucose oxidation in steps
Reduces the activation energy so that reaction can happen at 37’C
Reduces the free energy released
Can be coupled to endergonic reactions in cells
Does not damage the cell
Provides convenient control points
Can be integrated with other cellular communication
Electron flow in chemotrophs
Organic compounds (carbohydrates, amino acids, lipids) are oxidised to release high energy electrons
Organic cofactors act as electron carriers
NAD+ + 2 H+ is reduced to NADH + H+
FAD + 2H+ is reduced to FADH2
A terminal electron acceptor is reduced
aerobically: O2 —> H2O
Energy-centred view of metabolism
Nutrients such as glucose+O2 are catabolized, oxidative exergonic, and turn to CO2 +H2O
ADP+Pi are catabolized to atp,
ATP is anabolised to ADP+Pi
Enzymes
They are proteins that catalyse the conversion of a substrate into a product
They often require co-enzymes, ATP
They perform most chemical reactions in cells
What is the simple rule in naming enzymes
The enzyme name is derived from its substrate and its action:
Substrate action- ase
What is a function and an example of a oxidoreductases?
Function: All the enzymes catalyzing oxide-reductions
Example: Alcohol dehydrogenase
what are a function and an example of a transferase?
Function: Transfer a group onto a substrate
Example: UMP kinase
what are a function and an example of a hydrolase
Function: Catalyse the hydrolysis of various bond
Example: aminoacyl- tRNA hydrolase
what are a function and an example of a Lysases
Function: Cleave C-C, C-O, C-N, and other bonds by other means by then by hydrolysis or oxidation
Example: pyruvate decarboxylase
what are a function and an example of an isomerase
Function: Catalyse changes within one molecule
Example: DNA topoisomerase
what are a function and an example of a Ligase
Function: Catalyse the joining of two molecules with concomitant hydrolysis of diphosphate bond in ATP or a similar triphosphate
Example: DNA ligase (ATP)
what is the name and give an example of an enzyme that transfers phosphate groups
Name: Kinase
Example: Phosphofructokinase
what is the name and give an example of an enzyme that rearranges molecules
Name: Isomerase
Example: Isomerase
what is the name and give an example of an enzyme that makes a molecule from parts
Name: Synthase
Example: ATP synthase
what is the name and give an example of an enzyme that removes hydrogen
Name: Dehydrogenase
Example: Isocitrate dehydrogenase
what is the name and give an example of an enzyme that removes phosphate from proteins
Name: Phosphate
Example: Dual specificity phosphate.
What is a function and example of transferases
Function: Transfer a group onto a substrate
Example: UMP kinase
how does glucose transport into cells
via passive facilitated diffusion through glucose transporters
GLUT1
Tissue: Brain
Characteristics: Low Km
GLUT2
Tissue: Liver, pancreatic beta cells
Characteristics: High Km, insulin dependent
GLUT3
Tissue: Brain
Characteristics: Low Km
GLUT4
Tissue Muscle, adipose tissue
Characteristics: Insulin dependent
GLUT
Tissue: Gut
Characteristics: Fructose dependent
