Studied by 3 people
Percentage of CHON in an organism’s weight
A. 95.5%
B. 96%
C. 96.5%
96.5%
It is a crucial property of any bond, measured by the amount of energy that must be supplied to break the bonds. (expressed in kJ/mol or kcal/mol)
Bond strength
What are the four noncovalent attractions that help bring molecules together in cells?
Ionic bonds
hydrogen bonds
Van der Waals forces
hydrophobic forces
Acids, especially weak acids, will give up their protons more readily if the concentration of H3O+ in the solution is (high, low).
Low
Many biologically important molecules contain this functional group in weak bases
Amino (NH2) group
Its presence maintains the neutrality of the cell interior and keeps the cell environment relatively constant under a variety of conditions
Buffers
The four major families of small organic molecules
sugar
fatty acids
nucleotides
amino acids
T OR F.
Small organic molecules are more abundant than the organic macromolecules
False
These are less abundant, accounting for only about one-tenth of the total mass of the organic matter in the cell.
Principal building blocks from which a cell is constructed
Macromolecules
Three functions of proteins in cells
As catalysts (enzymes)
Structural components
Molecular motors
The reaction by which each polymer grows by the addition of a monomer onto the end of a growing chain
Condensation reaction
Enzyme-catalyzed reactions are connected in series, so that the product of one reaction becomes the _____ for the next reaction
Substrate
Another term for anabolic pathway
Biosynthetic pathway
Biological order is made possibly be the release of ____ from cells
Heat energy
Second law of thermodynamics
The degree of disorder always increases in the universe or any isolated system
T OR F.
Higher disorder = higher entropy
True
What does the first law of thermodynamics say?
Energy can be converted from one form to another, but it cannot be created or destroyed
The first law of thermodynamics tells us that the total amount of energy must always be the same
True
Cells obtain energy from the _____ of organic molecules
A. oxidation
B. hydrolysis
C. condensation
Oxidation
Reduction reaction has (lower, higher) CH bonds and (gains, loses) electrons.
Oxidation reaction has (lower, higher) CH bonds and (gains, loses) electrons.
Reduction - Higher CH bonds; gain of electrons
Oxidation - Lower CH bonds; loss of electrons
Each enzyme binds tightly to a substrate and greatly (a) increases (b) decreases the activation energy
(B) decreases
T OR F.
Activation energy is always negative
False
Activation energy is always positive, but the total energy change for the energetically favorable reaction is negative
T OR F.
An enzyme can speed up a reaction, but it cannot change its direction.
True
An enzyme cannot change the equilibrium point for a reaction. Since it lowers the activation energy for the reaction (Y-X), it also lowers the activation energy for the reaction (X-Y) by EXACTLY the same amount
Molecules are also in constant translational motion, which causes them to explore the space inside the cell through _____
A. translational motion
B. collisions
C. diffusion
Diffusion
T OR F.
The stronger the binding of the enzyme and substrate, the faster their rate of dissociation
False
Slower rate of dissociation
It is a measure of the spontaneity of a reaction
Free energy change (delta G)
T OR F.
A negative delta G means higher disorder and energetically unfavorable reaction
False
Energetically favorable
T OR F.
The concentration of reactants influences the free-energy change of a reaction, as well as its direction
True
For example, a reversible reaction Y ←→ X , a large excess of Y over X will tend to drive the reaction in the direction of Y → X. Thus, as the ratio of Y to X increases, the delta G becomes more negative for the transition Y → X
A measure for comparing the relative energies of different types of reactions
A. Free energy change
B. Standard free energy change
Standard free-energy change
Formula of delta G (free energy change) when standard free-energy change is given
R
T
delta G0
ln
[X], [Y]
delta G = delta G0 + RT ln [X] / [Y]
RT = 2.58 J/mole
X and Y = concentrations of reactants, mol/L
Formula for equilibrium constant, K
K = [X] / [Y]
Another term for activated carriers
A. Coenzymes
B. Cofactors
C. Ions
Coenzymes
The formation of an activated carrier is coupled to an _____ reaction
Energetically favorable
Spontaneous
Inside the cell, the ratio of NAD+ to NADH is kept (high, low) whereas the ratio of NADP+ to NADPH is kept (high, low).
High
Low
Activated form of coenzyme A
Acetyl CoA
Hydrolysis reaction (spontaneous) is coupled by ____ reaction for ATP hydrolysis
Condensation
Net gain of one round of glycolysis
2 3C pyruvate
-2 ATP +4 ATP = +2 ATP
2 NADH
During anaerobic conditions, the pyruvate and NADH from glycolysis stay in the ____
Cytosol
Fermentation will take place.
Why does fermentation require a higher glucose input than a normal oxidation process?
During anaerobic conditions, the cells cannot utilize oxygen to produce ATP. Since glycolysis has less ATP gain, the cell will need more glucose input to compensate the ATP it needs
What two steps in glycolysis that create high-energy phosphate linkage directly from Pi? This accounts for the net yield of 2 ATP and 2 NADH.
A. Glucose to G6P; G6P to F6P
B. DHAP to G3P; G3P to 1,3 BPG
C. G3P to 1,3 BPG; 1,3 BPG to 3-PG
Step 6 - G3P to 1,3 BPG
Step 7 - 1,3 BPG to 3-PG
Both plants and animals store food molecules through fats. But for short-term reserves, what reservoirs are they using?
Starch for plants
Glycogen for animals
Sugars and fats are both degraded to ____ in mitochondria for citric acid cycle
Acetyl CoA
Sugar → pyruvate → acetyl CoA, CO2, NADH
Fats → fatty acyl CoA → acetyl CoA, FADH2, NADH
The TCA accounts for about what fraction of the total oxidation of carbon compounds in most cells?
2/3
The TCA cycle does not use gaseous O2; instead, it uses oxygen atoms from ____
Water (H2O)
Net result of Krebs Cycle
3 NADH
1 FADH2
1 GTP
2 CO2
Site of:
Glycolysis
Krebs Cycle
ETC
Cytosol
Mitochondrial matrix
Inner mitochondrial membane
The total complete oxidation of a glucose molecule to water and carbon dioxide produces how many ATP molecules?
30 ATP
What are the 9 essential amino acids?
PVT TIM HALL
phenyalanine
valine
threonine
tryptophan
isoleucine
methionine
histidine
leucine
lysine
