Biology 1 Test 2
The passive movement of a substance along its concentration gradient is termed:
diffusion
In a reaction in which the rate of the reverse reaction is equal to the rate of the forward reaction, a state of __________ is attained.
dynamic equilibrium
During chemiosmosis, __________ are transferred from NADH and FADH2 to electron acceptor molecules, and the energy released is used to create a(n) __________ gradient across the inner mitochondrial membrane.
electrons; proton
The transfer of electrons from one compound to another is equivalent to __________ transfer.
energy
Every type of chemical bond contains a certain amount of energy. The total bond energy, which is essentially equivalent to the total potential energy of the system, is a quantity known as:
enthalpy
Which word is defined by this statement: A measure of this disorder, or randomness?
entropy
The reaction ATP + H2O → ADP + Pi is classified as an:
exergonic reaction
Select the enzyme that does not match the reaction:
kinase-breaks peptide bonds
Select the molecule that contains the most stored chemical energy:
lactate
The life and death of cells are governed by:
laws of thermodynamics
12 H2O + 12 NADP+ + 18 ADP + Pi → 6 O2 + 12 NADPH + 18 ATP summarizes the __________ reactions of photosynthesis.
light dependent
The reactions that occur in the thylakoid membranes are:
light dependent reactions
The reactions of photosynthesis are divided into two categories:
light-dependent reactions and carbon fixation reactions
One gram of __________ contains more than twice the amount of energy of a gram of glucose.
lipids
An electron absorbs a photon of light energy and becomes energized; the electron shifts from a __________ atomic orbital to a __________ atomic orbital.
lower energy; higher energy
Enzymes are important biological catalysts because they:
lower the activation energy of a biochemical reaction
The higher the concentration of solute in a solution, the __________ the effective water concentration and the __________ the osmotic pressure.
lower, higher
The thylakoid membrane encloses a space called the:
lumen
Integral proteins are
made by ribosomes located on the rough endoplasmic reticulum.
In C4 plants, reactions that fix CO2 into four-carbon compounds occur in:
mesophyll cells
The sum of all chemical activities taking place in an organism is:
metabolism
Which of the following accurately represents the relationship between the terms anabolism, catabolism, and metabolism?
metabolism = catabolism + anabolism
conditions are aerobic, pyruvate flows directly into the __________ where some of its atoms are converted next to __________.
mitochondia; acetyl coenzyme A
Select the hydrogen acceptor molecule that stores electrons in the process of photosynthesis:
nicotinamide adenine dinucleotide phosphate (NADP+)
Receptor-mediated endocytosis:
occurs when specific molecules combine with receptor proteins in the plasma membrane.
Which of the following membrane activities does NOT require the expenditure of energy by the cell?
osmosis
__________ is a process where energy (as electrons) is released, whereas __________ is a process where energy (as electrons) is accepted.
oxidation-reduction
In aerobic respiration, glucose is completely:
oxidized to carbon dioxide
XH2 + NAD+ → X + NADH + H+. In the preceding equation, NAD+ is said to be in a ____________ state and NADH is in a __________ state.
oxidized, reduced
In aerobic respiration, the electrons associated with the hydrogen atoms in glucose are ultimately transferred to:
oxygen in a series of steps
A human white blood cell engulfs a bacterial cell by:
phagocytosis
The synthesis of ATP during photosynthesis or respiration occurs as a result of:
phosphorylation of ADP
Plants, algae, and certain prokaryotes are:
photoautotrophs
Light behaves not only as waves, but also as particles called:
photons
The process by which light energy is converted into the stored chemical energy of organic molecules is:
photosynthesis
By definition, substances that absorb visible light are called
pigments
The __________ of a chlorophyll molecule is(are) responsible for absorbing light.
porphyrin ring
Energy stored within the molecules of ATP is in the form of __________ energy.
potential
In glycolysis, a six-carbon glucose molecule is converted to two three-carbon molecules of:
pyruvate
Aerobic respiration is classified as:
redox process
In the overall reactions of photosynthesis, it appears that hydrogen atoms are transferred from water to carbon dioxide to form a carbohydrate. This type of reaction is classified as:
redox reaction
During aerobic respiration, oxygen is:
reduced
Aerobic respiration, anaerobic respiration, and fermentation:
release free energy
facilitated diffusion
requires a specific transport protein
A bottle of perfume is opened on the opposite side of the room and within minutes you begin to smell the perfume. This phenomenon is a classic example of:
simple diffusion
Biological membranes are normally permeable to:
small hydrophobic molecules
Simple diffusion may involve the movement of __________ through the plasma membrane down a concentration gradient.
small nonpolar molecules
In the cotransport of glucose and sodium ions:
sodium ions are transported down their concentration gradient
An exergonic reaction is considered to be:
spontaneous
In a chloroplast, there is an outer and an inner membrane. The inner membrane encloses a fluid filled region called the:
stroma
The substance on which an enzyme acts is called the:
substrate
The ultimate source of energy for almost all living organisms is:
sun
Competitive inhibitors inhibit enzymatic reactions by:
temporarily bonding into the active site.
The chemical reaction illustrated in the figure is:
the energy investing phase of glycolysis.
The transfer of electrons from glucose to oxygen during aerobic respiration takes place in a stepwise fashion through a number of intermediates rather than by direct transfer. This is because:
the energy of the electrons can be used to make ATP
The role of the oxygen molecules required for aerobic respiration is:
to accept the low energy electrons at the end of the electron transport chain
integral proteins
Are amphipathic.
Figure 9-1 Use the figure to answer the corresponding question(s).
Gas exchange
The chlorophyll molecule has a porphyrin ring that contains a single atom of:
Magnesium
Which of the following statements concerning enzymes is FALSE?
Most enzymes are RNA molecules
Select the reduced molecule:
NADH
Which of the following is not one of the intermediates or products of the carbon fixation reactions?
NADPH
Which of the following statements is not correct about lactic acid fermentation?
Oxygen is the final electron acceptor of this pathway.
Which of the following molecules is least likely to cross a cellular membrane by simple diffusion?
Potassium ion
Figure 9-2 Use the figure to answer the corresponding question(s).
Red and blue wavelengths
The first step in the Calvin cycle is the attachment of carbon dioxide to:
RuBP (ribulose bisphosphate)
Who proposed the fluid mosaic model of cell membrane structure in 1972?
Singer and Nicholson
Consider a U-tube that initially contains pure water on one side of a selectively permeable membrane and water plus solute on the other side. Which of the following best describes what will happen next
Some water molecules become "bound up" with solute molecules and do not diffuse freely.
Engelmann concluded that chlorophyll in the chloroplasts is responsible for photosynthesis based on the following results:
The action spectrum of photosynthesis matched the maximum production of oxygen by Spirogyra, observed by the greatest accumulation of bacteria in the blue and red regions of the spectrum.
Which of the following statements is true of spontaneous reactions?
The amount of free energy after the reaction is less than before the reaction.
Which of the following is not a characteristic of aquaporins?
They cause dehydration
Which of the following statements concerning phospholipids is FALSE?
They contain three fatty acids chains.
Which of the following statements concerning decarboxylation reactions is FALSE?
They involve the removal of two protons and two electrons.
Which of the following statements concerning anabolic reactions is FALSE?
They may split complex molecules into their components.
In the experiment in which Frye and Edidin fused the plasma membranes of a mouse and a human cell, what happened to the membrane proteins?
They moved laterally across the cell surface.
Which of the following statements is contrary to the first law of thermodynamics?
When gasoline is burned, its energy is destroyed.
Catabolic reactions involve the:
breakdown of large organic molecules to simple building blocks
Organismal body heat is a:
byproduct of exergonic reactions
glucose molecule that is metabolized via aerobic respiration has been completely broken down and released as CO2 by the end of:
citric acid cycle
Select the processes that are matched with the incorrect amount of ATP produced by that process per glucose molecule.
citric acid cycle-4 ATP
Which refers to an organic, nonpolypeptide compound that binds to the apoenzyme and serves as a cofactor?
coenzyme
During the citric acid cycle, each acetyl group entering the cycle yields:
1 ATP, 3 NADH, 1 FADH2
Figure 9-3 Use the figure to answer the corresponding question(s).
3
Figure 9-1 Use the figure to answer the corresponding question(s).
3 an 4
When one molecule of glucose is completely oxidized in aerobic respiration, the net amount of ATP produced is:
36-38
In the skeletal muscle cells of vertebrates, as many as __________ molecules of ATP are produced from one molecule of glucose. This is less than might be expected, because electrons from NADH produced during glycolysis must be shuttled through the ____________ membrane at a cost.
36; mitochondrial
Figure 9-3 Use the figure to answer the corresponding question(s).
4
In the citric acid cycle, two acetyl CoA molecules are metabolized to:
4 CO2 + 6 NADH + 2 FADH2 + 2 ATP
The overall reactions of photosynthesis are best summarized as:
6 CO2 + 12 H2O → C6H12O6 + 6 O2 + 6 H2O
Select the compound that contains the most energy:
ATP
Thylakoid membranes are involved in __________ synthesis.
ATP
Which of the following is an end product of glycolysis?
ATP
the electron transport chain, exergonic redox processes drive the endergonic reaction in which:
ATP is produced by phosphorylation of ADP
chemiosmosis, ATP is produced as hydrogen ions (protons) pass through:
ATP synthase
Chlorophyll
Absorbs red and blue light and reflects green light.
Figure 9-2 Use the figure to answer the corresponding question(s).
Absorption spectra for chlorophylis a and b.
Which of the following are accessory photosynthetic pigments that expand the spectrum of light that provides energy for photosynthesis:
Both carotenoids and chlorophyll b.
The overall reaction for the aerobic respiration of glucose is summarized as:
C6H12O6 + 6 O2 + 6 H2O --> 6 CO2 + 12 H2O + energy
During the reactions of photosynthesis, __________ is reduced and __________ is oxidized.
CO2 and H2O
The reactants of the Calvin cycle are:
CO2, ATP, NADPH
Which of the following is not associated with the thylakoid membranes?
Calvin Cycle
Which of the following statements concerning activation energy is FALSE?
Catalysts raise a reaction's activation energy.
Which of the following describes how facilitated diffusion is powered?
Energy is required to do the work of establishing and maintaining a concentration gradient.
Noncyclic electron transport needs a constant supply of electrons. These are obtained from:
H2O
Oxygen produced by photosynthesis comes directly from:
H2O
The reactants of the light-dependent reactions are:
H2O, ADP, NADP+
What is meant by the term "fluid mosaic model"?
It is the movement of proteins within the phospholipid bilayer.
Which of the following statements concerning ATP is FALSE?
It stores energy for long periods
Which of the following statements about the sodium-potassium pump is true?
It transports 3 sodium ions out of the cell in exchange for 2 potassium ions.
Select the receptor mediated endocytosis events that are in the correct (before, after) order
Ligand binds to receptors; coated vesicle forms by endocytosis.
In photosynthesis, ATP and NADPH are produced during:
Light dependent phase
Select the molecule that contains the least stored chemical energy:
Oxygen
In cells that are constantly involved in secretion, an equivalent amount of membrane must be returned to the interior of the cell for each vesicle that fuses with the plasma membrane; if this does not occur, then what would happen?
The cell surface will keep expanding.
Which of the following statements about the electron transport chain is true?
The proton gradient established during electron transport is a form of potential energy.
Figure 7-1 Use the figure to answer the corresponding question(s).
The reaction is endergonic, and also the products have more free energy than the reactants.
Hydrolases are one important class of enzyme that function to catalyze:
The splitting of a molecule using water
Figure 5-1 Use the figure to answer the corresponding question(s).
These red blood cells have shrunken in response to a hypertonic external solution.
If phospholipids form a spherical structure when placed in water, then which of the following is the most logical conclusion about those phosopholipid molecules?
They are cone-shaped.
Parts of the enzyme molecule that interact with a substrate are called:
active sites
Even though a bacterium contains a higher concentration of sodium ions than in the surrounding pond water, the sodium ions continue to enter the bacterium. Evidently, sodium ions are entering the cell by:
active transport
Peter Mitchell demonstrated ATP production by aerobic bacteria by placing the bacteria in:
an acidic environment
When the free energy of the reactants is greater than the free energy of the products, such a reaction is referred to as:
an exergonic reaction
An organism can exchange matter and energy with its surroundings. Thus, any change in an organism's energy content must be balanced by a corresponding change in the energy content of the surroundings. As such, an organism is referred to as:
an open system
Pathways that have an overall energy requirement are referred to as:
anabolic reactions
Saturated fatty acids store more energy than unsaturated fatty acids. Based on your knowledge of aerobic respiration, you draw this conclusion because saturated fatty acids:
are more highly reduced.
During fermentation, the immediate fate of the electrons in NADH is that they:
are transferred to an organic molecule.
All of the following are functions of the cell membrane EXCEPT:
being freely permeable to all substances
Chlorophyll absorbs primarily __________ and __________ regions of the visible spectrum.
blue and red
Peripheral proteins are linked to either surface of the plasma membrane by:
bonding to integral proteins through noncovalent interactions.
Carrier proteins are involved in:
both facilitated diffusion and active transport
Anaerobic respiration differs from aerobic respiration in that anaerobic respiration:
can utilize NO3- as the terminal electron acceptor.
Cellular respiration is most accurately described as a(n) __________ process.
catabolic
The splitting of molecules into smaller components is referred to as:
catabolism
Because enzymes affect the speed of chemical reactions without being consumed, they are referred to as:
catalysts
Figure 7-2 Use the figure to answer the corresponding question(s).
change in free energy.
When hydrogen ions (protons) are pumped across the inner mitochondrial membrane, they form a proton gradient. ATP is then formed by a process known as:
chemiosmosis
Which of the following is common to both photosynthesis and aerobic respiration
chemiosmosis
Animals, fungi, and many bacteria that use organic molecules as a source of both energy and carbon are:
chemoheterotrophs
The most important pigment(s) for the process of photosynthesis is(are):
chlorophyll a
Reaction center complexes of the light-dependent reactions contain __________ and __________, which receive energy from __________.
chlorophyll; proteins; antenna complexes
The action spectrum of photosynthesis best matches the absorption spectrum of:
chlorophylls a and b
One product of the initial (first) reaction of the citric acid cycle is:
citrate
Consider the following two chemical equations: A. glucose + fructose → sucrose + H2O, ΔG = +27kJ/mole (or +6.5 kcal/mole) B. glucose + fructose + ATP → sucrose + ADP + Pi, ΔG = -5kJ/mole (or -1.2 kcal/mole)
combining an endergonic and an exergonic reaction.
A transmembrane protein differs from other membrane proteins because it:
completely extends through the membrane.
In order for a cell to maintain a high degree of order, it must:
constantly use energy
In eukaryotes, glycolysis occurs in the:
cytosol
Select the anaerobic pathway
fermentation
The production of alcohol or lactate from pyruvate during __________ occurs as a means of regenerating __________ from _________
fermentation; NAD+; NADH
Cholesterol within membranes functions as a(n) __________ through its interactions with both hydrophobic and hydrophilic parts of phospholipids.
fluidity buffer
Electrons that are excited to a higher energy level may be transferred to an electron acceptor or may return to a ground state. If the latter occurs, energy can be released as an emission of light in a process known as:
fluorescence
Considering only glycolysis and the conversion of pyruvate molecules to acetyl CoA molecules, how many NADH molecules will be produced from one glucose molecule?
four
What is the correct sequence of wavelengths (beginning with the shortest)?
gamma rays, x-rays, UV, visible light, infrared, microwaves, TV and radio waves
Plasmodesmata of plant cells are functionally equivalent to __________ of animal cells.
gap junctions
Select the phosphorylation reaction:
glucose + ATP → glucose-P + ADP
Studies of glucose transport in liposomes have revealed that:
glucose binds to the carrier protein causing the carrier protein to change its shape during the transport process.
Which of the following molecules can provide energy through cellular respiration?
glucose, lipids, proteins
Which process does not match the location in a typical eukaryotic cell?
glycolysis-mitochondrion
A group of thylakoid discs make up:
granum
A patient who has had a severe hemorrhage accidentally receives a large transfusion of distilled water directly into a major blood vessel. You would expect this mistake to:
have serious, perhaps fatal consequences because the red blood cells could swell and burst.
Which of the following does not represent a method by which cells regulate enzyme activity?
heat denaturation of the enzyme
ATP is formed when __________ the thylakoid lumen.
hydrogen ions leave
FAD and cytochromes are classified as:
hydrogen or electron acceptors
Which of the following is not one of the four stages of the aerobic respiration of glucose?
hydrolysis
In a lipid bilayer, __________ fatty acid tails face each other within the bilayer and form a region that excludes water.
hydrophobic
If the concentration of solutes in a cell is less than the concentration of solutes in the surrounding fluid, then the extracellular fluid is said to be:
hypertonic
Penicillin is toxic to certain dividing bacterial cells because it prevents cell wall formation, causing the cells to burst. This indicates that the bacteria live in:
hypotonic medium
If one continues to increase the temperature in an enzyme-catalyzed reaction, the rate of the reaction:
increases and then decreases rapidly.
What refers to the situation in which the binding of a substrate to the enzyme causes a change in the enzyme's shape, facilitating an enzyme's function?
induced fit
One important regulation point in the aerobic respiration of mammals occurs in glycolysis at the site of the enzyme phosphofructokinase, which is:
inhibited by high levels of ATP
Penicillin is a drug that acts by:
irreversibly inhibiting transpeptidase
A wilted flower placed in a vase of water for several hours became stiff and stood erect. When a fresh flower was placed in a salt solution, it wilted. From this information we can say that:
the fresh water is hypotonic and the salt solution is hypertonic to the cells of the flower.
The maintenance of a high ATP to ADP ratio within cells ensures that:
the hydrolysis of ATP to ADP will be strongly exergonic.
A drowning death would be most directly due to:
the lack of oxygen to accept hydrogen
Pinocytosis
the nonspecific uptake of fluids by pinching inward of the plasma membrane.
Although glucose molecules constantly diffuse into a cell along their concentration gradient, equilibrium is never reached and glucose continues to enter the cell. This is a direct result of:
the rapid and continuous formation of glucose phosphates within the cell.
Which of the following statements about lipid bilayers is FALSE?
they are inflexible
The electron transport chain of photosynthesis is located in the:
thylakoid membrane
Chlorophyll and accessory photosynthetic pigments are associated with the:
thylakoid membranes
Coenzyme Q:
transfers electrons
Glycolysis yields a net energy profit of __________ ATP molecules per molecule of glucose.
two
How many electrons are needed to reduce one molecule of NADP+ to NADPH?
two
Deamination of amino acids in mammals yields amino groups that are converted to __________, which is(are) excreted, and __________, which is(are) converted to one of the reactants of glycolysis or the citric acid cycle.
urea; carbon chains
An ABC transporter:
uses the energy of ATP to transport solutes
Most components of energy conversion systems evolved very early; thus, the most fundamental aspects of energy metabolism tend to be:
very similar in a wide range of different organisms
During the light-dependent reactions of photosynthesis, a constant supply of electrons is provided by:
water
The electrons lost by the P680 reactive center are replaced from:
water molecule
The ability of some bacteria to produce lactate is exploited by humans to make:
yogurt and sauerkraut
