Test Two: BIOL 1105 LIPSCOMB
with 100% correct
answers(graded A+)
What is thermodynamics? - answer The branch of chemistry
concerned with energy changes, heat changes especially.
Cells are ________, and as such they are governed by the laws of
chemistry and physics. - answer Chemical systems
Energy is- - answer The capacity to do work
What are the two states of energy? - answer Kinetic: energy of
motion
Potential: Stored
What are the forms of energy? - answer Mechanical, heat, sound,
electric current, light, and radioactivity.
What is the best way to measure energy? - answer by measuring
heat
What are the units when heat is measured? - answer calories. 1
calorie= Heat required to raise 1 gram of water 1 degree
Ion gradients represent ________ for active transport - answer
potential energy
,Energy flows into the biological World from the sun and then- -
answer Photosynthetic organisms capture this energy, convert it
into potential energy in chemical bonds. Energy is stored in the
covalent bonds of sugar, the more bonds the more energy.
Cells commonly convert one form of chemical energy into another
through- - answer chemical energy
What is oxidation? - answer Atom loses an electron, lower energy
What is reduction? - answer Atom gains an electron, more energy
What is the first law of thermodynamics? - answer Energy cannot
be created or destroyed, it can only change from one form to
another. The total amount of energy in the universe remains
constant
During conversions some energy is- - answer lost as heat (KE)
What is the second law of thermodynamics? - answer Entropy
(disorder) is continuously increasing. Energy transformations
proceed spontaneously to convert matter from a more ordered (less
stable) form to a less ordered (more stable)
What is the Gibbs Free Energy equation? - answer G= H - TS
G: Energy available to do work
H: enthalpy, energy in a molecule's bonds
T: absolute temperature
S: entropy, unavailable energy
What is Enthalpy? - answer Energy in a molecule's chemical bonds
,What does delta G predict? - answer Whether or not the reaction
will be spontaneous.
What does a positive delta G mean? - answer Energy is required to
proceed, because the products have more energy than the
reactants. Not spontaneous, termed Endergonic.
What does a negative delta G mean? - answer Tends to occur
spontaneously, products have less free energy than reactions,
termed Exergonic. Often need energy input to start.
What is activation energy? - answer Extra energy needed to
initiate a chemical reaction. The energy destabilizes existing bonds.
An exergonic's reaction rate depends on- - answer the activation
energy require. The larger the AE, the slower the reaction rate since
it is more difficult for molecules to overcome the initial activation
requirement.
How can you increase the reaction rate? - answer Increase energy
of reactant molecule (add heat)
Use a catalyst to lower AE.
Why do cells rely on catalysts? - answer Cells have a limited
temperature range, due to potential denaturation.
What is a catalyst? - answer Substances that influence chemical
bonds, they cannot violate the laws of thermodynamics though
(cannot make an endergonic reaction spontaneous)
What is Adenosine Triphosphate? - answer Source of chemical
potential energy, the main energy currency for all cells. This is
, because it has a low AE, bonds are easy to break. It is a nucleotide
with high energy bonds between phosphate groups.
Enzymes are- - answer Biological catalysts
What macromolecule are enzymes? - answer Many are proteins,
and some are RNA.
What does an enzyme do to catalyze a reaction? - answer An
enzyme orients and stresses bonds in substrates to lower AE. This
process does not change the enzyme. They differ cell-to-cell, and
may be soluble/ associated with membranes.
What is the active site? - answer Pocket or cleft for substrate
binding through which the enzyme-substrate complex is formed. It
has a precise fit for a substrate, and applies stress to distort bonds
to lower AE.
What is an induced fit? - answer When an enzyme changes its
shape to maximize contact with substrate.
What is a Multi-Enzyme complex? - answer A group of subunits that
work together to form a molecular machine. The product is
delivered easily to the next enzyme, unwanted side reactions are
prevented, and reactions can be controlled as a unit.
What are Ribozymes? - answer Non-protein enzymes that catalyze
peptide bond formation.
What factors influence enzyme function? - answer Concentration of
substrate and concentration of enzyme
any condition that affects structure can also affect rate (temp, pH,
regulatory molecules)
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