Part 3: Cellular Energetics Flashcards
Enzymes
Biological catalysts; enable cells to break chemical bonds without using (much) energy; speed up reaction without changing it by lowering the reaction’s activation energy
Bioenergetics
The study of how cells carry out the processes necessary for life, and the way in which cells release energy when they need it and store it when they don’t; how energy from the sun is transformed into energy in living things
Exergonic reactions
Products have less energy than reactions, energy is given off during reaction
Endergonic reactions
Reactions that require an input of energy; products have more energy than reactants
Activation energy
Energy required to start a reaction and break the chemical bonds of the reactants; energy barrier
Enzyme specificity
Property of enzymes that they can only catalyze one type of reaction; each enzyme can only bind to one specific substrate
Substrate
Targeted molecules in an enzymatic reaction
Active site
Place on the enzyme that a substrate binds to
Enzyme-substrate complex
Molecule formed by the binding of a substrate onto an enzyme
Induced fit
Enzyme slightly changes shape to accommodate substrate
Coenzymes
Organic factors that aid an enzyme in catalyzing a reaction; accept electrons and pass them on to another substrate; ex. Vitamins
Cofactors
Inorganic molecules that help catalyze reactions; usually metal ions (Fe+2)
Allosteric sites
Sites other than the active site that other substances can bind to
Allosteric regulators
The “other substances” that can bind to the allosteric site to inhibit or activate enzymes
Allosteric inhibitor
Allosteric regulator that inactivates the enzyme
Allosteric activator
Allosteric regulator that induces an enzymes function
Feedback inhibition
Formation of an end product inhibits an earlier reaction in the sequence
Competitive inhibition
A substance that has the shape that fits the active site of an enzyme blocks the substrate from binding to the active site and inactivates enzyme
Noncompetitive inhibition
Inhibitor binds with enzyme at a place other than the active site and inactivates enzyme by changing its shape
First law of thermodynamics
Energy cannot be created or destroyed
Second law of thermodynamics
Energy transfer leads to less organization; universe tends toward chaos (entropy)
Entropy
Chaos, disorder
Photosynthesis
Transformation of solar energy into chemical energy
6CO2 + 6H2O + sunlight –> C6H12O6 + 6O2
Cellular respiration
C6H12O6 + 6O2 –> 6CO2 + 6H2O + ATP
Way to synthesize ATP
Aerobic or anaerobic
Aerobic respiration
Cell resp. in the presence of O2
Anaerobic respiration
Cell resp. not in the presence O2
Glycolysis
Splitting of glucose; stage one of cell resp.; occurs in cytoplasm, net 2 ATP, products: 2 pyruvate (3C molecules) and 2 NADH
Pyruvic acid (pyruvate)
3-Carbon molecules, formed from glucose in glycolysis
4 fates: acetyl CoA (aerobic), lactic acid (anaerobic), glucose (glyconeogenesis), or
Parts of the mitochondria
Matrix- innermost area
Inner mit. Memb.
Intermemb. Space
Outer mit. Memb.
Acetyl CoA
2C molecule formed from pyruvate during transition reaction
Krebs cycle (citric acid cycle)
acetyl CoA combines with oxaloacetate (4C) to form citric acid (6C) and continues thru cycle
Products: 1 ATP, 3 NADH, 1FADH2, 2CO2 per pyruvate (x2 to get per glucose)
Cytochromes
Iron-containing carrier molecules in the electron transport chain
pH gradient (proton gradient)
Created by pumping H ions into the intermemb. space, energy from gradient responsible for the production of ATP
ATP synthase
Channels on the inner mit. memb. that H+ ions pass through to generate ATP
Oxidative phosphorylation
The process by which ATP is synthesized as a result of the flow of protons through the ATP synthase in the mitochondria 34 ATP (NADH makes 3, FADH makes 2)
Fermentation
Anaerobic resp.- pyruvate converted to either lactic acid (animals) or ethanol (plants)
