Lecture 6: Energy and Enzymes Flashcards
What is energy?
the capacity to do work
(exists in different forms; heat, light, electric, mechanical, chemical, nuclear)
Kinetic energy
The energy of motion, or the form of energy that is actually doing work
Potential energy
A form of stored energy, the capacity to preform work (ex. water behind a dam, fossil fuels)
Chemical energy
All chemical molecules store energy
Thermodynamics
the study of energy transformations that occur in a collection (thermodynamic system)
First law of Thermodynamics (the law of energy conservation)
The total amount of energy in the universe remains constant (energy can be changed from one form to another)
Second law of thermodynamics (the law of energy conservations)
reducing the order of the universe, increasing its entropy (randomness- the amount of disorder in a system)
Cellular metabolism
the sum of chemical activities within a living cell
Metabolic pathways
sequences of enzyme-catalyzed reactions (Anabolism and Catabolism)
Anabolism
refers to the various pathways in which complex molecules are synthesized from simple substrates
Catabolism
includes the pathways in which larger molecules are broken down in smaller ones
Chemical reaction
the change in the composition or distribution of atoms of a substance, involving the making and/or breaking of chemical bonds with consequent alterations in properties
Free energy
the amount of a systems energy that can preform work when temperature and pressure are uniform throughout the system, as in a living cell
spontaneous reaction
a chemical reaction which will proceed on its own, without any outside influence
exergonic reaction
an energy-releasing chemical reaction yielding products that contain less potential energy than their reactants
endergonic reaction
an energy-requiring chemical reaction yielding products rich in potential energy
energy coupling reaction
the use of energy released from exergonic reactions to drive essential endergonic reaction
Energy of reaction
the amount of energy that reactants must absorb before a chemical reaction will start (represents the energy barrier)
enzyme
a protein that serves as a biological catalyst
Cofactor
these are inorganic ions such as iron, copper, or zinc that bind to certain enzymes
coenzyme
small carbon-containing molecules such as coenzyme A (CoA), NAD, FAD, or ATP
prosthetic group
these distinctive molecular groups are permanently bound to their enzymes such as heme or flavin
ATP
(Adenosine 5’- triphosphate)
the energy currency/shuttle of the living cell
structure of ATP
A nucleotide consisting of 3 parts:
- adenine
- ribose
- 3 phosphate groups
function of ATP
hydrolysis of ATP- an exergonic reaction
ATP + H20 —-> ADP + Pi + TriangleG
ATP donates energy through the transfer of a phosphate group
generation of ATP by 2 ways:
-substrate-level phosphorylation
- chemiosmosis
Oxidative phosphorylation
ATP synthesis driven by electron transfer to oxygen
Photophosphorylation
ATP synthesis driven by light
oxidation
the chemical process in which a substance loses electrons
reduction
the complementary process to oxidation in which a substance gains electrons
redox reactions
oxidation and reduction occurring together simultaneously
[NAD^+ - NADP]
Nicotinamide adenine dinucleotide
[NADP^+ - NADPH]
nicotinamide adenine dinucleotide phosphate
[FAD^+ - FADH2]
flavin adenine dinucleotide
2 important structure (organelles) involved in cellular energy conversion
Chloroplast + mitochondrion
