Chapter 7 Vocab Flashcards
What do cells do with energy?
convert it from one form to another
what is radiant energy?
the ultimate source of energy (photosynthesis; sun’s energy –> chemical energy)
what is matter?
anything at has mass and takes up space
what is energy?
the capacity to do work (change in state or motion of matter)
how much energy do photosynthetic organisms capture?
about 0.02%
how is energy expressed in units of work?
kilojoules, kJ
how is energy expressed in units of heat energy?
kilocalories, kcal
what does 1 kcal equal?
4.184kJ
what is thermodynamics?
heat and temperature and its relation to energy and work
mass is technically energy, what is the equation?
E=mc^2
what is potential energy?
the capacity to do work as a result of position or state (water behind a dam)
what is kinetic energy?
energy of motions is used, work is performed (water falling through a turbine)
what is an energy transformation?
occurs in series, kinetic energy is converted to potential energy or potential energy to kinetic
what is chemical energy?
potential energy stored in chemical bonds (food –>mechanical energy for muscles)
what does thermodynamics govern?
all activities of the universe
biological systems are?
open systems that exchange energy with their surroundings
what type of system is the universe?
closed
what is the first law of thermodynamics?
energy cannot be created or destroyed, only transferred or converted
-energy is the system plus sits surrounding
how do organisms obey the first law of thermodynamics?
by capturing energy from the environment and transforming it to a form that can be used for biological systems
according to the first law of thermodynamics, what happens to mass-energy of an object?
mass-energy does not change, it can only go from one form to another
what is the second law of thermodynamics?
during energy transformations, usable energy/energy available to do work is converted into heat and given off
what is heat
the kinetic energy of randomly moving particles or less- usable energy “disorganized energy”
what happens to usable energy according the second law of thermodynamics?
as heat is loss, the amount of usable energy available decreases over time
what is entropy?
the measure of the disorder or randomness of energy, organized and disorganized (Unusable energy in a system)
what is organized/order energy?
usable energy that has a low entropy
what is disorganized/disorder energy?
energy (like heat) that has a high entropy
what happens to total energy over time?
the total entropy of the universe always increases over time
energy conversion are never?
100%
what is entropy (S)?
the quantitative measure of the increase in disorder or randomness that occurs with energy transformation
equation for the first and second law of thermodynamics
H=G+S
Enthalpy (H), Entropy (S), Free Energy (G)
what is free energy?
energy that is available to do cellular work, chemical reaction involve change in free energy (deltaG)
What is the relationship between free energy and entropy?
inversely related
total free energy in a system cannot be measure, but what can?
changes in free energy
deltaG=deltaH - T deltaS
relationship between total energy and entropy?
total energy is constant and entropy always increases
what is metabolism?
all chemical reactions taking place in an organism (also includes intersecting chemical reactions like anabolism + catabolism)
what is anabolism?
pathways in which complex molecules are synthesized from simpler substance (REQUIRES ENERGY)
what is catabolism?
pathways in which larger molecules are broken down into smaller ones (GIVES OFF ENERGY)
what is an exergonic reaction?
a reaction that releases energy and is a “downhill” reaction, from higher to lower free energy ; deltaG is negative
what is activation energy?
energy needed to initiate every reaction even spontaneous ones, energy required to break existing bonds and begin a reactions
what is an endergonic reaction?
a reaction in which there is a gain of free energy, delta G is positive and the free energy of the products is greater than the free energy of reactants (REQUIRES AN INPUT OF ENERGY)
what is the relationship between exergonic and endergonic reactions?
exergonic reactions supply energy for endergonic reactions
what type of reaction is diffusion?
exergonic, the movement. of particles down their concentration gradient creates energy
what is a concentration gradient?
an orderly state with a region of higher concentration and another region of lower concentration (cells must expend energy to produce a gradient)
endergonic reactions couple with?
exergonic reactions
what is a coupled reaction?
thermodynamically favorable exergonic reaction provides energy require to drive a thermodynamically unfavorable endergonic reaction
what do exergonic reactions in cells involve?
the breakdown of ATP
what is Adenosine Triphosphate (ATP)
nucleotide consisting of adenine, ribose, and 3 phosphate groups; used to temporarily store energy in cells, hydrolysis of ATP yields ADP and inorganic phosphate
what is the ratio of ATP to ADP in a cell
more than 10 ATP for every ADP
what do high levels of ATP do?
make the hydrolysis reaction more strongly exergonic, and more able to drive coupled endergonic reactions
why is ATP constantly used and replaced?
the cell cannot store large quantities of ATP
how much ATP do humans use?
45Kg ATP a day
how many ATP do cells make per second?
10 million ATP per second
what is a redox reaction?
a series of electron transfers (cellular respiration, photosynthesis, etc)
what is oxidation?
when a substance loses electrons
what is reduction?
when a substance gains electrons
redox reaction in cells usually involve?
the transfer of H+
what happens to an electrons free energy as it is transferred to different acceptors?
free energy is progressively lost
what does NADH do in cellular respiration?
tranfers elections, the energy is then transfered in a series to reaction to form ATP
where is NADPH used?
used in photosynthesis
what is Flavin adenine dinucleotide (FAD)?
nucleotide that accepts hydrogen atoms and their electrons (reduced form is FADH2)
what are cytochromes?
proteins that contain iron, iron accepts electrons from H+ atoms and transfers them to another compounds
what are enzymes?
increase the speed of a chemical reaction without being consumes by the reaction
what is catalase?
has the highest known catalytic rate, protects cells by destroying H2O2
what is an Enzyme Substrate complex?
an unstable complex which breaks up and releases product
The ES complex contains?
an enzyme + substrate
what is an active site?
the region where a substrate binds on an enzyme
what is induced fit?
binding of a substrate to the enzyme causes a change in enzyme shape (distort the chemical bonds of a substrate)
what facilitates the breakage and formation of products?
proximity and orientation of reactants plus strains in chemical bonds
what makes enzymes specific?
shape of the active site, specific to certain chemical bonds, protein structure
what are the two components of enzymes?
apoenzyme and cofactor (non protein)
what is a cofactor?
a specific metal ion (iron, copper, zinc, and manganese)
what cofactors does the enzyme DNA polymerase have?
magnesium and zinc
what are coenzymes?
organic nonpolypeptide compounds that bind to the apoenzyme and serves as a cofactor
what carrier molecules do most coenzymes contain?
NADH, NADPH, FADH2 (transfer electrons); ATP (to transfer phosphate groups); coenzyme A (transfer group derived from organic acids)
what are most vitamins?
coenzymes or components of coenzymes
what do enzymes have regarding temperature?
optimal temperature
what are heat tolerant archaea?
certain archaea that have enzymes allowing them to survive extreme habitats
what is the optimal pH for human enzymes?
between 6 to 8
Enzymes are specific to what?
temperature, pH, and shape
what are metabolic pathways?
the product of one enzyme-controlled reaction serves as substrate for the next series of reactions
what does the removal and intermediate and final products do?
drive the sequence of reaction in a particular direction
what is a multi enzyme complex?
when enzymes bind to one another; transfers intermediate in the pathway from one active site to another
what is gene control?
when a specific gene directs synthesis of each type of enzyme; genes can be turned on by a signal (hormone or molecule), amounts of the enzymes influence overall cell reaction rate
what can limit rate of reaction?
enzyme concentration or substrate concentration
relationship between rate of reaction and enzyme concentration?
directly proportional
how is rate of reaction measured?
at different enzyme concentrations with an excess of substrate present (temp and pH are constant)
the product of one enzymatic reaction can?
fuel the next reaction
what is feedback inhibition?
enzyme regulation in which the formation of a product inhibits an earlier reaction in the sequence
what is an allosteric site?
modifies the enzyme activity when the enzyme is bound to it “another space”. keeps the enzyme in an inactive states
what do allosteric activators do?
result in a functional active site
what is competitive inhibition?
the inhibitor competes with the normal substrate for the active site of the enzyme (occupies the active site temporarily)
what is a noncompetitive inhibitor?
the inhibitor binds with the enzyme at a site other than the active site, altering the shape of the enzyme and thereby activating it
what is irreversible inhibition?
inhibitor permanently inactivates or destroys an enzyme when the inhibitor combines with one of the enzyme’s functional groups (at the active site or elsewhere), most poison (mercury, lead, nerve gases, cyanide)
