Ch. 6 Flashcards
What is metabolism?
the overall chemical reactions occuring within an organism at a given time
consists of catabolic and anabolic pathways
What is a metabolic pathway?
a series of chemical reactions that either build or destroy complex molecules
2 types: catabolic and anabolic
What is an anabolic pathway?
consumes energy to synthesize a complex molecule from simpler molecules
What is a catabolic pathway?
releases energy by breaking down complex molecules to simpler molecules
What are bioenergetics?
the study of how energy flows through organisms
What is energy?
the ability to cause change, especially the ability to do work
What is kinetic energy?
energy in motion
What is potential energy?
stored energy
What is chemical energy?
a form of potential energy where it is available in molecules for release in a chemical reaction
What is the First Law of Thermodynamics?
“energy can be transferred and transformed, but cannot be created nor destroyed”
principle of conservation of energy
What is the Second Law of Thermodynamics?
“every energy transfer or transformation increases the entropy of the universe
usable forms of energy partly converted to heat
What are thermodynamics?
the study of the energy transformations that occur in a collection of matter
What is entropy?
a measure of molecular disorder or randomness
What is delta G?
the symbol for the change of free energy
delta G = G final state - G initial state
What is free energy?
the energy that is available to do work
What is an exergonic reaction?
a spontaneous chemical reaction that leads to a net release of free energy
energy-releasing process
What is an endergonic reaction?
a non-spontaneous chemical reaction; free energy is absorbed from its surroundings
energy-consuming process
Is cellular respiration exergonic or endergonic?
exergonic
Is photosynthesis exergonic or endergonic?
endergonic
What is adenosine triphosphate? (ATP)
a molecule that releases free energy when its phosphate bonds are hydrolyzed
What are the 3 kinds of cellular work?
- chemical work
- transport work
- mechanical work
What is chemical work?
pushing of endergonic reactions that would NOT occur spontaneously
What is transport work?
pumping of substances across a membrane against the direction of spontaneous movement
What is mechanical work?
cell motility and movement of structures within cells
What is the ATP cycle?
the process by which cells regenerate ATP
* ADP forms when a phosphate group is removed from ATP
* ATP forms again when ADP forms a phosphate group
What are catalysts?
chemical agents that speed up chemical reactions
What are enzymes?
a type of macromolecule (usually proteins) that serve as biological catalysts within living systems
What is activation energy?
the amount of energy that is needed for a chemical reaction to start
catalysts lower the EA for reactions –> speeds up reaction rate
What is a substrate?
the reactant on which an enzyme works
What is an active site?
a region on an enzyme that binds to a protein or other substance during a reaction
What is an allosteric site?
a site that allows molecules to either activate or inhibit (or turn off) enzyme activity
What is a competitive inhibitor?
substances that reduce the activity of an enzyme by entering the active site in place of the substrate, who structure it imitates
What is a noncompetitive inhibitor?
substances that reduce the activity of an enzyme by binding to an allosteric site separate from the active site
binds its target enzyme regardless of the presence of a bound substrate
What is feedback inhibition?
- where an enzyme’s activity is inhibited by the enzyme’s end product
- allows cells to regulate how much of an enzyme’s end product is produced
