Biology Unit 3
Terms
undefined, object
copy deck
- First law of thermodynamics
- total energy in the universe is constant (energy is neither created nor destroyed)
- second law
- total usuable energy in a system decreases as energy conversions take place (given off as heat). This increases entropy (randomness, disorder)
- free energy
- amount of energy available to break and reform bonds
- Delta G
- -=exergonic reaction, energy releasing
- coupled reaction
- endergonic reactions can occur when coupled to series or pathways of reactions that are exergonic ("domino effect")
- active sites on enzymes
- a place or area on a protein that is determined by its tertiary structure
- substrates
- bind to specific active site of a specific protein. (after a substrate binds it shifts tertiary strucutre which may enhance of inhibit further bonding. known as induced fit
- How do enzymes lower activation energy?
-
-increase local concentration of molecules
-position molecules in relation to each other so they can bond - competitive inhibition
- a molecule other than the usual substrate binds in the active site and blocks normal product formation
- allosteric effects
-
molecules bind on enzyme somewhere other than the active site but still affect aite by altering tertiary structure
-non-competitive inhibition - cofactors
- molecules that assit in enzyme function
- metal ions
- can pull electrons away from substrate molecules because of their charge
- coenzymes
- cofactors that are non-protein organic molecules. often operate to transfer electrons between molecules, therefore are redox pairs
- multienzyme complexes
- increase efficiency of catalytic events by increasing concentration of reactants, decreasing competeing reactions, operating as a unit
- ATP structure
-
-one nitrogen base-adenine
-one sugar-ribose
-one-three phosphate group - ATP hydrolysis
-
-liberates 7 Kcal/bond
-drives endergonic reactions
-phosphorylates-add a phosphate functional group
-can cause couple reactions - glycolysis
-
sugar splitting, occurs in the cytoplasm of all cells
-energy obtained from breaking the C-H bonds of glucose - Glycolysis reaction
-
6 carbons (glucose) yields 2 molecules of pyruvic acid (3 carbons)
-net yield= 2 ATP, 2 NADH - Kreb's cycle
-
-occurs in the matrix of the mitochondria
-1 ATP per turn - electron transport chain
-
electrons are passed from glucose to oxygen in a series of steps with electrons "falling", releasing stored energy at each step.
-occurs in the inner inner mitochondrial membrane, the cristae - cellular respiration of fats
-
in the matrix lipids either become
1. glycerol or fatty acid
2. broken down into fatty acids (chains)->2 carbon pieces (acetyl groups) -> acetyl CoA - Fermentation
-
-anaerobic respiration
-conversion of pyruvic acid to either ethanol or lactic acid
-small amount of ATP made - chloroplasts
- the only pigment that directly converts light energy to chemical energy by boosting electrons to higher energy levels
- CAM
- stomates stay closed during the day, but open at night