Bio Unit 3

What is energy?

the ability to do work

What are the two different forms of energy?

potential and kinetic

What is electrical energy?

movement of charged particles

What is thermal energy?

energy of motion in ions and molecules

What is potential energy?

energy related to position

What is kinetic energy?

energy related to movement

What is mechanical energy?

movement of mass

What is free energy?

total energy available to do work, combination of entropy and amount of thermal and potential energy involved

What is change in free energy?

final minus initial free energy

What is important about free energy in relation to reactions?

reactions are spontaneous when free energy of products is less than the free energy in reactants

What is ATP?

adenosine triphosphate, source of energy, adenine with 3 phosphate groups

Why is ATP important?

high in potential energy due to negative charges in phosphate that repel each other

What is energetic coupling?

when phosphorylation raises the potential energy of a molecule to make chemical reaction happen that was non spontaneous at first

How does phosphorylation affect spontaneity of a reaction?

phosphorylation helps make a nonspontaneous reaction spontaneous because it raises the free energy of the reactants

What is thermodynamics?

study of energy flow during chemical and physical reactions

What are the 2 laws of thermodynamics?

1. total amount of energy within a system remains constant, energy cannot be created or destroyed, only transferred or transformed

   1. total entropy of the system and its surroundings always increases

What is an exergonic reaction?

reaction in which free energy is released, products have less free energy than the reactant, reaction is spontaneous and denoted as -ΔG

What is an endergonic reaction?

reaction in which free energy is required, the products have more free energy than the reactions, the reaction is nonspontaneous and is denoted as +ΔG

What are enzymes?

proteins that act as catalysis’s, make reactions go faster but aren’t change by said reaction

What is an enzyme active site?

area on an enzyme in which a particular chemical reaction takes place, enzymes catalyze only a specific reaction due to the shape size and chemical composition of the active site

What is activation energy?

amount of energy require to get a chemical reaction through the transition state

How do enzymes affect reactions?

lower activation energy needed for the reaction to occur

What is a competitive enzyme inhibitor?

inhibitor that binds to the active site on the enzyme and competes with the actual substrate

What is a non-competitive/allosteric enzyme inhibitor?

inhibitor that binds to the allosteric site (site away from active site) of an enzyme and causes the enzyme to change shape and therefore its active site

What is the general sequence of cell signaling?

reception → transduction → response

signaling molecule is released in response to stimulus, signal is synthesized and stored, messenger travels from source cells to target cells, signal binds to receptor in target cell, receptor protein changes shape and triggers events that lead to cell changing activity

What is a hormone?

molecule that acts as a long-distance signal between cells in the same multicellular individual

What is a ligand?

any molecule that binds to a receptor

What are the types of molecules that function as cell signals?

amines, peptides, steroids

What are amines?

amino acids

What are peptides?

small proteins

What are steroids?

lipid with four fused rings, synthesized from cholesterol

What is lipid soluble?

molecule is small and hydrophobic, can enter interior of target cell to receptor

What is water soluble?

molecule is large and hydrophilic, cannot enter interior of target cell so binds to receptor on membrane

What is an intracellular receptor?

receptor in cell that binds to a hydrophobic ligand

What is a membrane receptor?

receptor in membrane that binds to a hydrophilic ligand

What is signal transduction?

events that convert one type of signal to another type

What is kinase?

enzyme that catalyzes the addition of a phosphate group from ATP to another molecule