Cellular energetics Flashcards
First law of thermodynamics
No energy can be lost within the universe
Energy can be converted from one form into another
Second law of thermodynamics
Every energy transfer increases the entropy (chaos) of the universe
Takes the environment into account
Cellular respiration
Metabolic process with which an organism obtains energy by oxidising nutrients and releasing waste products
Anabolism
Use energy to build complex molecules
Catabolism
Release energy through molecule breakdown
Example of anabolism?
Protein synthesis from amino acids
Example of catabolism?
Breakdown of glucose in glycolysis
Enzymes regulate…
Metabolism
What are metabolic pathways made up of?
A group of enzyme-catalysed reactions
Exergonic reaction
Energy released
Endergonic reaction
Energy required
Enzymes lower activation energy and are…
- pH dependent
- Regulated by gene expression and protein modification
- Often inhibited by end product (negative feedback)
When does ATP release energy?
When the outermost inorganic phosphate (P) is cleaved off and yields ADP
Where is energy stored?
In outermost Pi because negative charged repel each other
How is ATP formed?
Substrate-level phosphorylation (transfer of phosphate group)
Oxidative phosphorylation (chemiosmosis)
What is chemiosmosis?
Movement of ions down their electrochemical gradient across a semipermeable membrane
