Bio Exam 2
A + B --> C + D Given the Gibb's Free Energy (G) values listed below, what is the ∆G for the reaction listed above and how would this reaction best be characterized? A + B = 12 kcal/mol C + D = 18 kcal/mol
+6 kcal/mol; endergonic
On the enzyme diagram below, identify what A, B, and C are labelling (in order).
Active site, substrate, allosteric site
Mitochondria are found in ___ and chloroplasts are found in ___. - For this statement, please ignore cells such as red blood cells which may be exceptions.
All eukaryotic cells; photosynthetic eukaryotic cells
Which statement about the dark reactions (light independent reactions) of photosynthesis is accurate?
During the dark reactions carbon is fixed and then reduced.
What is the correct sequence for secreted protein movement through the endomembrane system?
ER, cis-Golgi, trans-Golgi, vesicles
Which produce the most ATP?
ETC and chemiosmosis
Which stage of glucose metabolism produces the most ATP?
Electron transport and chemiosmosis
Which of the following statements about photosynthesis is accurate?
Electrons taken from water during the light reactions are used to reduce carbon during the Calvin cycle.
Which enzyme below is being allosterically inhibited?
Enzyme D
Can a catalyst alone make a nonspontaneous reaction occur spontaneously? Explain why or why not.
No, a catalyst affects only the activation energy, not the overall change in Gibbs free energy.
How many molecules of ATP would you need to hydrolyze to make a reaction with a ΔG = -12 kcal/mol go in a biological system?
None because no ATP would be needed to make that reaction go in a biological system.
net input of oxidative phosphorylation
O2, NADH, ADP
Photosystem II Only:
Oxidation of water; reduction of electron transport chain between two photosystems
ATP is produced during the light reactions of photosynthesis using a mechanism very similar to one observed during cellular respiration. Which mechanism from cellular respiration is this?
Oxidative phosphorylation
During the process of glycolysis the carbon in glucose is ____; to complete the complementary redox reaction, we see ____ produced in this process
Oxidized; NADH
While the electron transport chain is running NADH is ____ when it gives its electrons to complex I; to complete the complementary redox reaction, we see ____ produced by electron transport chain proteins.
Oxidized; Water
Which of the following would not be considered a reactant for the citric acid cycle?
Oxygen
During the Calvin cycle, carbon dioxide is _____ to drive the formation of sugars.
reduced
When a compound accepts (gains) electrons, that compound becomes ___________. Such a compound is often referred to as an electron acceptor.
reduced
Enzymes work by _____.
reducing EA (activation energy)
Photosystem I Only:
reduction of NADP+; oxidation of electron transport chain between two photosystems
PS II & PS I:
reduction of electron acceptor; light absorption
Which features are common to all cells?
cytoskeleton; ribosomes; genetic information (DNA); the cytoplasm; the plasma membrane
Which of the following in the figure would be the same in either an enzyme-catalyzed or a noncatalyzed reaction?
d
An enzyme is _______________ when it loses its native conformation and its biological activity.
denatured
A chemical reaction that has a positive ΔG is best described as _____.
endergonic
Why is measuring the rate of oxygen production in chloroplasts appropriate for estimating the rate of photosynthesis?
Oxygen is produced by "splitting" water in the photosystem II complex.
The evolution of eukaryotic cells most likely involved _____.
endosymbiosis of an aerobic bacterium in a larger host cell—the endosymbiont evolved into mitochondria
When the noncompetitive inhibitor is bonded to the enzyme, the shape of the _________ is distorted.
enzyme
When ATP is hydrolyzed into ADP and inorganic phosphate, _____.
free energy is released
During cellular respiration ____.
glucose is oxidized and there is net production of ATP
In glycolysis, the carbon-containing compound that functions as the electron donor is __________.
glucose.
In eukaryotes, the components of the electron transport chain are located in the ____.
inner mitochondrial membrane
between:
inter-
Endocytosis moves materials _____ a cell via _____.
into ... membranous vesicles
Which of the following statements best describes the relationship between photosynthesis and respiration?
Photosynthesis stores energy in complex organic molecules; respiration releases energy from complex organic molecules
K + Br --> K+ + Br -
Potassium is oxidized; Bromine is reduced
How are proteins transported to their correct location in the cell?
Proteins contain molecular "zip codes" that allow them to be shipped to the correct cellular compartment.
If a photosynthetic pigment were to absorb all wavelengths of light from 450nm to 800nm, what color would you expect that pigment to be?
Purple
Which of the following products of glycolysis is/are transported into the mitochondrion as the process of respiration runs its course?
Pyruvate and NADH
Which steps are responsible for glucose oxidation?
Pyruvate processing; Glycolysis; Citric acid cycle
Net output of glycolysis
Pyruvate, NADH, ATP
This cellular component: 1) is present in both prokaryotic cells and all eukaryotic cells, and 2) performs the same function in both cell types.
Ribosome
Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH 8 solution. What would most likely happen?
The isolated chloroplasts would make ATP.
Which set of reactions uses H2O and produces O2?
The light-dependent reactions
Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis?
The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.
What is the importance of the light-independent reactions in terms of carbon flow in the biosphere?
The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.
Usually, a(n) ___________ inhibitor forms a covalent bond with an amino acid side group within the active site, which prevents the substrate from entering the active site or prevents catalytic activity.
irreversible
As a result of its involvement in a reaction, an enzyme _____.
is unchanged
Asbestos is a material that was once used extensively in construction. One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers. Cells will phagocytize asbestos, but are not able to degrade it. As a result, asbestos fibers accumulate in _____.
lysosomes
Which of the following cell structures would you expect to be required for this function of the cells?
lysosomes
Which are specific to just animals?
lysosomes; lack a cell wall
Which are specific to all eukaryotes?
mitochondria; endoplasmic reticulum; nucleus
Which organelle is the primary site of ATP synthesis in eukaryotic cells?
mitochondrion
Which plant cell organelle contains its own DNA and ribosomes?
mitochondrion
Both Animal and Plant Cells:
mitochondrion; endoplasmic reticulum; Golgi apparatus; cytoskeleton; nucleus; plasma membrane
Which of the following statements about prokaryotic / eukaryotic cells is not accurate?
The number of chromosomes in prokaryotes and eukaryotes is the same.
For living organisms, which of the following is an important consequence of the first law of thermodynamics?
The organism ultimately must obtain all of the necessary energy for life from its environment.
Select the reaction graph (Free Energy vs. Reaction Progress) that would depict a reaction with a ∆G = 17 kcal/mol.
The second graph
A(n) __________ _________ binds to a site on the enzyme that is not the active site.
noncompetitive inhibitor
Molecules move into and out of the nucleus through the _____.
nuclear pores
For each of the proteins described, would you expect it to be produced on a ribosome in the cytosol (ribosome) or a ribosome associated with the rough endoplasmic reticulum (RER)? - A hydrolysis enzyme that will be utilized in the lysosome - Microtubulin units that will be used in the cytoplasm to create microtubules during mitosis in a plant cell - A protein produced in a bacterium which plays a role in protection from heat - A sodium/potassium pump that a cell in a human uses to conduct active transport
- RER - ribosome - ribosome - RER
If the ATP hydrolysis reaction below were coupled to a different reaction with an overall ∆G = 3 kcal/mol, what would be the coupled ∆G? +7.3 kcal/mol
-4.3 kcal/mol
little, small:
-elle
body:
-some (or soma-)
How many molecules of ATP would you need to hydrolyze to make a reaction with a ΔG = 16 kcal/mol go in a biological system?
3.00
Which of these equations best summarizes photosynthesis?
6 CO2 + 6 H2O → C6H12O6 + 6 O2
How many molecules of ATP would you need to hydrolyze to make a reaction with a ΔG = 4 kcal/mol go in a biological system?
1.00
Based on the data from the pulse-chase experiment shown in the graph in Figure 7.20b, which is the best estimate for the time it takes for proteins to pass through the Golgi apparatus?
10-37 min; This is the time elapsed from when significant amounts of labeled proteins first appear in the Golgi apparatus (0 to 7 min) until they first appear in secretory vesicles (17 to 37 min). This is a reasonable estimate for the time it takes proteins to pass through the Golgi apparatus.
Net input of glycolysis
ADP, NAD+, glucose
Net output of Calvin Cycle:
ADP, NADP+, G3P
At the end of cellular respiration, protons flow through a protein called _____, which drives the formation of ATP from ADP and inorganic phosphate.
ATP synthase
Net output of light reactions:
ATP, NADPH, O2
Which of these enters the citric acid cycle?
Acetyl CoA
This molecule contains the carbon remaining from glucose which can still be oxidized at the beginning of the citric acid cycle step of cellular respiration.
Acetyl-CoA
Which of the following is an example of potential rather than kinetic energy? A. a crawling beetle foraging for food B. a molecule of glucose C. the muscle contractions of a person mowing grass D. light flashes emitted by a firefly E. water rushing over Niagara Falls
B
How would anaerobic conditions (when no O2 is present) affect the rate of electron transport and ATP production during oxidative phosphorylation? (Note that you should not consider the effect on ATP synthesis in glycolysis or the citric acid cycle.)
Both electron transport and ATP synthesis would stop.
Net input of Calvin Cycle:
CO2, ATP, NADPH
The electrons derived from this oxidation reaction in the Calvin Cycle are used to reduce _____ to _____.
CO2; G3P
Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?
Carbon dioxide
Which of the statements about the light reactions (light dependent reactions) of photosynthesis is not accurate?
Carbon dioxide is split by one of the photosystems and produces oxygen.
C3H8 + O2 --> CO2 + H2O
Carbon is oxidized; Oxygen is reduced
What central theme of biology helps explain why various cells can look so different from one another?
Cells correlate structure with function.
Which of the following statements is representative of the second law of thermodynamics?
Cells require a constant input of energy to maintain their high level of organization.
Where do plant cells and cyanobacteria (also photosynthetic) get the ATP they need to power their regular cellular processes?
Cellular respiration
What happens in box 9?
Citric Acid Cycle
Which answer correctly associates a process in cellular respiration with (1) what goes in and (2) what comes out?
Citric acid cycle: (1) Acetyl CoA; (2) NADH, ATP (or GTP), FADH2, and CO2
Which of the following is true for all exergonic reactions? A. The products have more total energy than the reactants. B. The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants. C. The reactions are rapid. D. The reaction proceeds with a net release of free energy. E. A net input of energy from the surroundings is required for the reactions to proceed.
D
Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?
Fermentation
Which statement best explains why more ATP is made per molecule of NADH than per molecule of FADH2?
Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor.
Which molecule is metabolized in a cell to produce energy "currency" in the form of ATP?
Glucose
Which statement is true of the following reaction? C6H12O6 + 6 O2 →→ 6 CO2 + 6 H2O
Glucose carbons are oxidized to carbon dioxide
What happens in box 2?
Glycolysis
Which step of the cellular respiration pathway can take place in the absence of oxygen?
Glycolysis
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
H2O → NADPH → Calvin cycle
In the light reactions, light energy is used to oxidize _____ to _____.
H2O; O2
Which statement most accurately explains how allosteric regulation can change an enzyme's catalytic activity?
In allosteric activation, a regulatory molecule binds to a location other than the active site, resulting in a change in enzyme shape that allows the active site to bind substrate.
Why is ATP an important molecule in metabolism?
It provides energy coupling between exergonic and endergonic reactions.
What purpose does fermentation serve?
It regenerates NAD+ from NADH to keep glycolysis going in the absence of oxygen.
Which of the following most appropriately list the products of the fermentation process in humans?
Lactic acid and NAD+
Glycolysis
Location: Cytoplasm
Citric Acid Cycle:
Location: Mitochondrial Matrix
Electron Transport and Oxidative Phosphorylation:
Location: Mitochondrial Matrix
Pyruvate Processing:
Location: Mitochondrial Matrix
Calvin Cycle:
Location: Stroma
Light-dependent Reactions:
Location: Thylakoid Membrane
Stage of cellular respiration: glycolysis
Location: cytosol
Stage of cellular respiration: oxidation phosphorylation
Location: inner mitochondrial membrane
Stage of cellular respiration: acetyl CoA formation
Location: mitochondrial matrix
Stage of cellular respiration: citric acid cycle
Location: mitochondrial matrix
For eukaryotic cells, which answer best describes the function of the indicated component?
Lysosome: waste-processing and recycling center
__________ is the compound that functions as the electron acceptor in glycolysis.
NAD+
Net output of oxidative phosphorylation
NAD+, ATP, water
Based on the data in Figure 9.13, which of the energy-storing molecules produced during glucose oxidation is expected to carry the highest amount of chemical energy?
NADH
The reduced form of the electron acceptor in glycolysis is _________.
NADH
Which of the following statements about the electron transport chain is true?
NADH and FADH2 donate their electrons to the chain.
The electrons derived from this oxidation reaction in the light reactions are used to reduce ____ to _____.
NADP+; NADPH
The light-independent reactions of plants function to make organic molecules using carbon dioxide as a carbon source. What is the electron source that helps reduce carbon dioxide to sugars and other organic molecules?
NADPH
Which of the following molecules is the primary product of photosystem I?
NADPH
What two molecules produced during the light-capturing reactions of photosynthesis are used in the Calvin cycle?
NADPH and ATP
During the light reactions, the captured light energy in Photosystem I is used ultimately to create ________, while the captured light energy in Photosystem II is used to ultimately create _________.
NADPH; ATP
The Calvin Cycle oxidizes the light-reactions products _____ to _____.
NADPH; NADP+
2 NO3- --> N2 + 3 O2
Nitrogen is reduced; Oxygen is oxidized
The pituitary gland produces growth hormones (GH) which is a protein-based hormone and the thymus produces cortisol which is a lipid-based hormone. Both of these hormones are secreted after being produced to provide systemic stimulus in the body. To accomplish this production, the pituitary gland will need a higher proportion of ___ and the thymus will need a higher proportion of ___.
Rough ER; Smooth ER
Which molecule is regenerated in the regeneration phase of the Calvin cycle? Without regeneration of this molecule, the Calvin cycle would stop.
RuBP
Over the course of the reaction below:
Sodium is oxidized
Researchers discover a novel organism which appears to produce its ATP in an unbelievable one-step process by breaking the bonds in higher energy creatine phosphate molecules (∆G = -10.3 kcal/mol) found in its environment. Based upon our understanding, we would expect this ATP to be produced in a way most similar to which mechanism that we use?
Substrate-level phosphorylation
Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst?
The catalyzed reaction will have the same ∆G.
Which statement most accurately describes what happens to proteins that lack an ER signal sequence?
They are released into the cytosol.
What is the biological significance of the light-independent reactions of photosynthesis?
They convert carbon dioxide to sugar.
Which statement is true for all redox reactions?
They involve the transfer of electrons.
True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
True
True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups.
True
True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria.
True
Which scenario demonstrates the highest level of entropy?
Water as a gas in the air
Select the reaction graph (Free Energy vs. Reaction Progress) that would depict a reaction with a ∆G = -14 kcal/mol.
a
Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as ________.
a cofactor necessary for enzyme activity
A prokaryotic cell is distinct from a eukaryotic cell because a prokaryotic cell lacks _____.
a nucleus
Spherocytosis is a human blood disorder associated with a defective cytoskeletal protein in the red blood cells (RBCs). What do you suspect is the consequence of such a defect?
abnormally shaped RBCs
Which of these is NOT a product of the citric acid cycle?
acetyl CoA
What three distinct elements make up the cytoskeleton in eukaryotic cells?
actin filaments (microfilaments), intermediate filaments, and microtubules
A substrate binds to an enzyme at the ____________ _____, where the reaction occurs.
active site
The competitive inhibitor competes with the substrate for the ______ ______ on the enzyme.
active site
water:
aqu- (or aqua-)
two:
bi-
Which of the following represents the activation energy required for a noncatalyzed reaction in the figure?
c
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
catabolism (catabolic pathways)
An enzyme is considered a _____________ because it speeds up chemical reactions without being used up.
catalyst
Animal Cell Only:
centriole
An allosteric inhibitor decreases the rate of an enzyme reaction by ________.
changing the shape of the enzyme's active site
Plant Cell Only:
chloroplast; cellulose cell wall; central vacuole
Which of the following cell structures is only found in algal and plant cells?
chloroplasts
color:
chrom-
A ______________, such as a vitamin, binds to an enzyme and plays a role in catalysis.
cofactor
HIV is the virus that causes AIDS. In the mid-1990s, researchers discovered an enzyme in HIV called protease. Once the enzyme's structure was known, researchers began looking for drugs that would fit into the active site and block it. If this strategy for stopping HIV infections were successful, it would be an example of what phenomenon?
competitive inhibition
A(n) ____________ __________ has a structure that is so similar to the substrate that it can bond to the enzyme just like the substrate.
competitive inhibitor
When properly aligned, the enzyme and substrate form an enzyme-substrate (ES) ___________.
complex
Which of the following mitochondrial activities would most likely be inhibited?
oxidative phosphorylation
When a compound donates (loses) electrons, that compound becomes ____________. Such a compound is often referred to as an electron donor.
oxidized
What molecule is released when water is split in the light reactions of photosynthesis?
oxygen
A white blood cell engulfing a bacterium is an example of _____.
phagocytosis
Which process produces oxygen?
photosynthesis
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
proteins
Once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called ____________.
pyruvate
Electrons tend to have more potential energy when ____.
they are in electron shells far from the nucleus
A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. Since the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed. If the power fails and the lights go dark, CO2 levels will _____.
rise as a result of both animal and plant respiration
Which structure is the site of the synthesis of proteins that may be exported from the cell?
rough ER
The enzyme that catalyzes the fixation of carbon dioxide in photosynthesis is _____.
rubisco
Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?
smooth endoplasmic reticulum
An enzyme is considered ______________ because of its ability to recognize the shape of a particular molecule.
specific
Enzyme inhibitors disrupt normal interactions between an enzyme and its ___________.
substrate
In a catalyzed reaction a reactant is often called a _____________.
substrate
What name is given to the reactants in an enzymatically catalyzed reaction?
substrate
In the citric acid cycle, ATP molecules are produced by _____.
substrate-level phosphorylation
During photosynthesis, the light energy from the sun is captured and stored in the bonds of _____.
sugars
Reactions that require CO2 take place in _____.
the Calvin cycle alone
A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because _____.
the activation energy barrier for this reaction cannot easily be surmounted at room temperature
You can recognize the process of pinocytosis when _____.
the cell is engulfing extracellular fluid
Which are specific to just prokaryotes?
the nucleoid (single, supercoiled chromosome)
In mitochondrial electron transport, what is the direct role of O2?
to function as the final electron acceptor in the electron transport chain
across:
trans-
For each molecule of glucose processed during glycolysis, the net yield is ____.
two molecules of NADH, two of ATP, and two of pyruvate
Rank these by reaction rate, as measured by the rate of product formation per unit time, from lowest reaction rate to highest reaction rate. To rank items as equivalent, overlap them.
uncatalyzed reaction; reaction catalyzed by enzyme A; reaction catalyzed by enzyme B
If you were to expose cells that are undergoing cellular respiration to a radioactive oxygen isotope in the form of O2, which of the following molecules would you expect to be radiolabeled?
water
The electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?
water
The light reactions of photosynthesis use _____ and produce _____.
water ... NADPH
Net input of light reactions:
water, light, NADP+, ADP
In the Z-scheme ____ is the initial electron donor and ____ is the final electron acceptor.
water; NADP+
During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a ∆G of −20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the ∆G for the new reaction?
−20 kcal/mol