Energy cannot be created or destroyed, Energy can be converted from one form to another
The universe is divided into system and surroundings.
DEFINE BOTH
System is a subset of the universe.
Surroundings are everything in the universe not part of the system
Systems can be closed or open.
DEFINE BOTH
Closed: systems exchange energy with surroundings
Open: systems exchange matter and energy with the surroundings
In energy transformations heat may be generated, work may be done.
T OR F?
First law does not predict + or - DE in a system
TRUE
TheSecond Law of Thermodynamics IS.....
In any energy transformation, entropy of the universe increases.
Entropy is a measure of disorder
T OR F ?
Living systems maintain a state of order by working against disorder, Keep entropy low.
TRUE
WHEN WATER FREZES, WHAT HAPPENS ENTROPY?
LOWERS
Combination of the first and second laws can be expressed mathematically...WHAT'S THE FORMULA?
-DH = DG + TDS
DS....entropy
DG....free energy (available to do work)
-DG is a measure of spontaneity of a reaction.
DG < 0, spontaneous reaction......Exergonic
DG > 0, reaction requires energy input .....Endergonic
DG < 0, spontaneous reaction
Exergonic OR Endergonic
Exergonic
DG > 0, reaction requires energy input
Exergonic OR Endergonic?
Endergonic
Cells are_______ thermodynamic systems
Open
(systems exchange matter and energy with the surroundings)
Cellular metabolism exists in a "steady state"...WHAT DOES THAT MEAN?
Concentrations of reactants to products remain constant, but not at equilibrium
New substrates enter; products removed.
Maintenance of steady state requires a constant input of energy
T OR F ?
Maintenance of steady state requires a constant input of energy
TRUE.
Maintaining equilibrium does not
IN A "STEADY STATE" WHAT IS THE CONCENTRATION OF ATP?
HIGH OR LOW?
HIGH.
ENZYMES CAN FUNCTION OUTSIDE OF CELLS, WHO DISCOVERED IT AND WHEN?
Hans and Eduard Buchner, 1897
WHO AND WHEN DISCOVERED ENZYMES ARE ALMOST ALWAYS PROTEINS?
James Sumner, 1926
Enzymes may be conjugated with protein & nonprotein
components...name them
Cofactors inorganic enzyme conjugates. EX:metals
carry out activities amino acids are not suited for.
Coenzymes: organic enzyme conjugates.
ENZYMES Cannot affect thermodynamics of a
reaction, only_______.
RATES
Reactants that reach the peak of activation energy barrier are in the _____ _______.
transition state
Potential energy is....DEFINE
stored energy--energy ready to go.
DEFINE KENETIC ENERGY
The kinetic energy of an object is the energy which it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
Catalysts like enzymes________ activation energy
LOWER
With a catalyst large proportions of substrates can reach the transition state
Charged R groups on the enzyme effect substrates...NAME 3 WAYS
ATTACK
BEND
LINK WITH
Cofactors of the enzyme increase the reactivity of the substrate by DOING WHAT ?
removing or donating protons
Inducing Strain in the Substrate..WHAT TYPE OF BONDS ARE STRAINED?
COLVALENT
Various changes in atomic and electronic structure occur in both enzyme and substrate
during reaction...NAME TWO WAYS TO VIEW THIS.
time-resolved crystalography
picosecond X-ray
DEFINE KINETICS
study of rates of enzymatic reactions under various experimental conditions
DEFINE THE TURNOVER NUMBER IN ENZYME KINETICS
The turnover number is number of substrate molecules converted to product/min/enzyme molecule at Vmax
DEFINE maximal velocity, Vmax
At saturation every enzyme molecule is working at maximal capacity
The velocity at saturation is called maximal velocity, Vmax
Enzyme Inhibitors...NAME THEM
Irreversible...... bind tightly to enzyme
Reversible.......bind loosely to enzyme
2 TYPES:
Competitive inhibitors: compete with enzyme for active sites.
Noncompetitive inhibitors: bind sites other than active site and inactivate enzyme
IF YOU HAVE AN ISSUE WITH REVERSIBLE, COMPETIVE INHIBITORS, HOW WOULD YOU OVERCOME IT?
can be overcome with high substrate/inhibitor ratios.
Of the following elements, which is likely to form the least polar covalent bonds with hydrogen:
A.nitrogen
B. oxygen
C. carbon
D. phosphorus
C. carbon
Of the following chemical bonds, which is the strongest in water?
A. HOH2C–CH2OH
The major cellular macromolecules include:
A. proteins, nucleic acids, carbohydrates, and lipids.
Which of the following has been used as evidence that primitive life forms lacked both DNA and enzymes?
A. RNA can both code genetic information and act as a
catalyst.
B. DNA and enzymes are only present in the most advanced cells.
C. Advanced cells lack RNA.
D. All of the above.
A. RNA can both code genetic information and act as a catalyst.
Of the following functional groups, which would make a carbon-based compound the least polar?
A. phosphate
B. methyl
C. carboxyl
D. amino
B. methyl
Cytoplasm has a pH of about 7. What is the concentration, in moles/liter, of the hydrogen ion?
1 x 10-7
Which of the following pairs of functional groups might form weak bonds with one another?
A. methyl and phosphate
B. phosphate and carboxyl
C. carboxyl and amino
D. carbonyl and methyl
C. carboxyl and amino
Proteins and macromolecular structures take on their higher order structures
A. by self-assembly.
B. with the help of molecular chaperones.
C. with the help of precursor sequences that are removed from the final structure.
D. all of the above.
A. by self-assembly.
Which amino acids would most likely reside in the membrane-anchoring domain of a membrane-embedded protein?
D. isoleucine, valine, and phenylalanine
ATP is from which general category of biomolecules?
A. polysaccharides
B. proteins
C. nucleotides
D. amino acids
C. nucleotides
LEAST LIKELY TO OCCUR IN A CELL?
A
DEFINE ENTROPY
THE GAIN/LOSS OF DISORDER
(DS)
DEFINE ENTHALPY
ENERGY GAIN OR NEEDED
(DH)
When sea water is evaporated leaving behind salt crystals, the entropy of the water is ________.
A. increased
B. decreased
C. unchanged
A. INCREASED
When a fertilized egg cell develops into an embryo, the entropy of the living system is ________.
A. increased
B. decreased
C. unchanged
B. decreased
Reactions that have positive standard free energy changes (ΔG'°>0) can be made to occur in cells by:
A. coupling them with exergonic reactions via a common intermediate.
B. manipulating the concentrations of products and reactants such that ΔG'<0.
C. coupling them to the hydrolysis of ATP.
D. all of the above.
D. all of the above.
Cellular metabolism is an example of:
A. equilibrium metabolism.
B. steady-state metabolism.
C. a series of reactions occurring under standard conditions.
D. a series of reactions that defy the second law of
thermodynamics.
B. steady-state metabolism.
Any system that is not at equilibrium:
A. is thermodynamically unstable, although it may be kinetically stable.
B. is kinetically unstable, although it may be thermodynamically stable.
C. is rushing toward equilibrium at a very rapid rate.
D. requires an enzyme to reach equilibrium.
A. is thermodynamically unstable, although it may be kinetically stable.
Protein catalysts:
A. increase the rates of chemical reactions in cells while remaining unchanged.
B. are sometimes referred to as ribozymes.
C. can change the standard free energy of a cellular
reaction.
D. all of the above.
A. increase the rates of chemical reactions in cells while remaining unchanged.
Which of the following statements is not true of enzymes?
A. Enzymes are proteins that bind to specific substrates and increase the velocity of reactions involving those substrates.
B. Enzymes function by overcoming the activation energy barrier of a reaction.
C. Enzymes can only make thermodynamically favorable reactions proceed; they cannot make unfavorable reactions occur.
D. Enzymes only function when they are in intact
cells.
D. Enzymes only function when they are in intact cells.
As opposed to an uncatalyzed reaction, in an enzymatically catalyzed reaction...what happens?
the activation energy of the reaction is lowered, and a larger proportion of substrate molecules has sufficient energy to overcome it.
A certain inhibitor of an enzymatic reaction was determined to act as a competitive inhibitor. Which one of following statements about the inhibitor is most probably true?
A. The inhibitor acts at a site other than the substrate binding
site.
B. The inhibitor increases KM but has no effect on
Vmax.
C. The inhibitor decreases KM but has no effect on Vmax.
D. The inhibitor lowers the maximum velocity of the
enzyme.
B. The inhibitor increases KM but has no effect on Vmax.
During glycolysis, a net of how many ATPs are produced for each glucose that enters the pathway?
A. 1
B. 2
C. 4
D. ≥35
B. 2
For most of the reactions of glycolysis, the ΔG under cellular conditions is close to 0. Why does the pathway continue in the direction of glucose catabolism?
There are three essentially irreversible (ΔG<<0) reactions that act as the “driving force” for the pathway.
All of the following techniques were used to study the mechanism of lysozyme action except:
D. site directed mutagenesis.
B. equilibrium thermodynamics.
JUST UNDERSTAND THIS:
JUST UNDERSTAND THIS:
Noncompetitive inhibitor ______ Vmax without affecting Km
REDUCES
Competitive inhibitor ________ Km without affecting Vmax
INCREASE
HOW DO Ab WORK?
targets:
bacterial metabolism, no harm to host
Enzymes involved in synthesis of the bacterial cell wall
genetic information transfers
Bacteria become resistant to antibiotics by acquiring genes from other bacteria...HOW?
Transformation,transduction, conjugation
T OR F ?
Pathways usually confined to specific cellular location but Enzymes of a given pathway may be physically linked to one another
TRUE
Catabolic pathways _______ ______complex substrates into simple end products..PROVIDE MATERIALS AND ENERGY
break down
Anabolic pathways ________complex end products from simple substrates, it ________energy.
synthesize
requires
Use ATP and NADPH from catabolic pathways
THE 3 STAGES OF METABOLISM.
NAME STRUCTURES IN EACH.
In redox pairs, the substrate that gains electrons is the _____
agent
oxidizing
The substrate that donates electrons is the _______ agent
reducing
With organic substrates redox involves atoms bound to ____.
CARBON
THERE ARE 2 STAGES IN THE CATABOLISM OF GLUCOSE..NAME THEM
GLYCOLYSIS FIRST IN CYTOPLASM
MAKES PYRUVATE ACID THEN TCA CYCLE
CARBON IN THE MOST REDUCED STATE IS ATTACHED TO WHAT? WHAT ABOUT MOST OXIDIZED STATE?
MOST REDUCED: 4 HYDROGENS, SINGLE BONDS.
MOST OXIDIZED: 2 OXYGEN
(DOUBLE BONDED TO EACH)
The oxidation state of a carbon atom...NAME THE GROUPS FROM MOST REDUCED TO MOST OXIDIZED.
WHEN YOU REDUCE ATOMS, WHAT DO YOU GET?
ENERGY
THINK Fats and carbohydrates are oxidized in cells to release energy to do work.
Chemical energy is transferred to form ATP
_________is the carbohydrate central to the
energy-producing pathways of cells
Glucose
T OR F ?
THE MORE A SUBSTANCE IS REDUCED THE MORE ENERGY CAN BE RELEASED.
TRUE
Kinase enzymes...FUNCTION
transfer phosphate groups
Substrate level phosphorylation occurs when ?
ATP is formed by a kinase enzyme
NAD+ IS AN OXIDIZING AGENT IN GLYCOLYSIS?
TRUE
DEFINE PHOSPHORYLATION
WHEN A PHOSOPHORUS GROUP IS ADDED TO A MOLECULE. IN GLYCOLYSIS, AN ENZYME ACT TO MOVE IT AROUND, KNOWN AS SUBSTRATE-PHOSPHORYLATION
hexokinase is an enzyme that does what ?
phosphorylates a six-carbon sugar, a hexose, to a hexose phosphate.
PHOSPATE FROM ATP.
1ST STEP OF GLYCOLYSIS.
THIS IS SUBSTRATE PHOSPHORYLATION
JUST KNOW THIS:
DEFINE Allosteric Feedback Inhibition
Flow of metabolites through metabolic pathway stops when end products inhibit the first enzyme in the pathway
Avoids wasting resources in the cell
Allosteric site binding causes conformational change and inhibits enzyme activity