Biology 6 - General Biology I » Spring 2021 » Exam 2

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Question #1
An enzyme is specific to its substrate because _________________________.
A.   it has to be the same size as the substrate
B.   its polarity has to be similar to the product's polarity
C.   the shape of its active site has to match the shape of the substrate
D.   its subunit molecules need to match the subunit molecules of the substrate
Question #2
Consider an energy-requiring metabolic pathway: A -> B -> C -> D Which statement is false?
A.   It is a anabolic.
B.   A is the initial substrate whereas D is the final product of the pathway.
C.   B & C are intermediates of the pathway.
D.   D is much smaller than A.
Question #3
When cell processes require energy to do work, ___________________________.
A.   ADP & phosphate are covalently bonded to make ATP
B.   Cell respiration enzymes are inhibited
C.   ATP gets converted to cyclic AMP & pyrophosphate
D.   High energy phosphate bond breaks off from ATP
Question #4
Consider the metabolic pathway “ A -> B -> C -> D ”. How many different kinds of enzymes are required to complete the metabolic pathway?
A.   5
B.   4
C.   2
D.   3
E.   1
Question #5
Which statement is true regarding life and the second law of thermodynamics (law of entropy)?
A.   As a consequence of being alive, organisms convert “useful” energy into dissipated (high entropy) heat.
B.   Living organisms do not actually obey the law of entropy.
C.   Life obeys the second law of thermodynamics but not the first law of conservation of energy.
D.   Living organisms decrease entropy in the universe while alive but increase entropy after they die.
Question #6
ATP is synthesized in all of the following metabolic pathways except ______________________.
A.   Krebs (Citric acid) cycle
B.   glycolysis
C.   light-independent reactions (Calvin cycle) of photosynthesis
D.   light-dependent reactions (cyclic & noncylcic electron flow) of photosynthesis
E.   Electron transport chain & chemiosmosis
Question #7
The action of enzymes is noncompetitively (allosterically) inhibited by certain poisons by _____________.
A.   binding to the enzyme and modifying the shape of the enzyme’s active site
B.   stabilizing the protein subunits of the enzymes
C.   pulling the substrates away from the enzyme
D.   filling the active sites and thus preventing the normal substrate to bind with the enzyme
Question #8
High amounts of __________ are able to turn off aerobic cell respiration.
A.   glucose and pyruvate
B.   H2O and O2
C.   ATP and citric acid
D.   NAD+ and FAD+
Question #9
Which event happens during Krebs (Citric acid) cycle?
A.   Glucose is split into two pyruvates.
B.   The product of glycolysis is further broken down to release more energy.
C.   Oxygen gas is used to make carbon dioxide.
D.   Glucose is synthesized using ADP & phosphate
Question #10
Which process in eukaryotic cells will proceed normally whether oxygen gas (O2) is present or absent?
A.   Krebs (Citric acid) cycle
B.   Electron transport chain
C.   Glycolysis
D.   Oxidative phosphorylation
Question #11
From “energy” perspective, which statement best describes the relationship between photosynthesis and respiration?
A.   Photosynthesis occurs only in plants and respiration occurs only in animals.
B.   Respiration runs the biochemical pathways of photosynthesis in reverse.
C.   ATP molecules are produced in photosynthesis and used up in respiration.
D.   Photosynthesis stores energy in complex organic molecules, whereas respiration releases it.
Question #12
In the absence of sugars, cells may use fats as fuel for respiration. Where do the 2-carbon catabolic products of fatty acid breakdown enter the aerobic respiration pathway?
A.   Krebs cycle
B.   Electron transport chain & chemiosmosis
C.   Calvin cycle
D.   Glycolysis
Question #13
Where in the cell do Krebs cycle & Electron transport chain occur?
A.   mitochondrion
B.   plasma membrane
C.   chloroplast
D.   cytoplasm
E.   nucleus
Question #14
In human cells, what ultimately happens to the high energy electron released during glycolysis if the person is not able to breathe properly?
A.   It combines with pyruvate to produce a fermentation product
B.   It is used as a raw material to synthesize fat molecules.
C.   It gets reused & goes through glycolysis a second time.
D.   It enters the mitochondria to combine with oxygen gas
Question #15
Which event does NOT occur during glycolysis?
A.   intermediates get oxidized by NAD+
B.   energy is released to produce ATP
C.   glucose is broken down into 2 three-carbon sugar
D.   pyruvate is converted into lactic acid
Question #16
In the thylakoid membrane, what is the main direct role of antenna pigment molecules in photosystems I & II?
A.   harvest light & transfer energy to the reaction-center special chlorophyll a
B.   synthesize sugar from carbon dioxide & water
C.   synthesize ATP from ADP and phosphate
D.   split water and release oxygen gas
Question #17
CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they ___________________________.
A.   fix CO2 into pyruvate in leaf epidermal cells
B.   use a different enzyme which outcompetes rubisco for CO2
C.   fix CO2 in mesophyll cells then export intermediates to the bundle-sheath cells where CO2 is recovered
D.   fix CO2 into organic acids during the night
Question #18
The leaves of a plant being green implies __________________________.
A.   photosynthesis uses green light as a source of energy
B.   photosynthesis must occur in plant leaves
C.   green light is absorbed by the leaves
D.   leaves are colored green under light & dark conditions
Question #19
When stomates are closed, which molecule accumulates inside the leaves undergoing photosynthesis? This condition may harm plants.
A.   water
B.   oxygen gas
C.   carbon dioxide
D.   glucose
Question #20
Photosynthesis involves the conversion of ____________________.
A.   glucose into lactic acid
B.   light into oxygen gas
C.   carbon dioxide int oxygen gas
D.   light into chemical energy
Question #21
Which molecules coming from the light dependent reactions of photosynthesis are utilized in the Calvin cycle?
A.   H2O and O2
B.   ATP and NADPH
C.   CO2 and glucose
D.   ADP and NADP+
Question #22
Which is a substrate of the light-dependent reaction (linear electron flow) of photosynthesis?
A.   glucose
B.   NADPH
C.   water
D.   ATP
Question #23
________________ is the enzyme that converts ATP into cyclic AMP, an important second messenger during signal transduction.
A.   Catalase
B.   Kinase
C.   Caspase
D.   Adenylyl cyclase
Question #24
A hormone binds with a G protein-coupled receptor of a target cell. What immediately happens next?
A.   A relay protein is phosphorylated.
B.   Conformational change in the receptor activates the G protein.
C.   The target protein is deactivated.
D.   Hormone replaces GTP with ATP in the G protein
Question #25
A pair of tyrosine kinases (that form a dimer) embedded in the plasma membrane serve as___________ of the signal pathway.
A.   local regulator
B.   second messenger
C.   relay protein
D.   hormone
E.   receptors
Question #26
Key to the cell’s continuing “receptiveness” to regulation is the _________________________.
A.   type of receptors the cell uses for communication
B.   reversibility of the binding of signaling molecules to their receptors
C.   role of cyclic AMP and calcium ions in signal transduction
D.   presence of enzyme inhibitors
Question #27
Which one best explains the fact that most signal transduction pathways have multiple (cascade) steps?
A.   Multiple steps in a pathway require the least amount of ATP.
B.   Each of the steps allow for flexible response.
C.   Each step can be activated by several G proteins simultaneously.
D.   Multiple steps provide for greater amplification of a signal.
Question #28
Which type of signaling molecules tend to have intracellular receptors?
A.   lipid-based such as steroids
B.   peptide-based such as insulin
C.   small & polar such as Ca ions
D.   local regulators
Question #29
_________________ catalyzes the reactions that phosphorylate proteins during the signal transduction pathway.
A.   Protein kinase
B.   Phosphatase
C.   Second messenger
D.   Catalase
Question #30
In the lab exercise on cell respiration in peas, the vial with __________ was a control for the possible unexpected changes in gas volume not related to cell respiration.
A.   soaked peas only
B.   soaked peas & beads
C.   beads only
D.   dry peas & beads
Question #31
Which evidence demonstrated that enzymes catalyze chemical reactions?
A.   Only the tube with starch by itself turned orange when tested with Benedict’s.
B.   Only the tube with starch & saliva combined turned orange when tested with Benedict’s.
C.   All tubes tested with Benedict’s reagent turned orange in color.
D.   All tubes tested with iodine remained blue/black in color.
Question #32
What is the role of the sugar in the lab exercise that combined it with water & yeast? It was the ____________________.
A.   substrate
B.   enzyme
C.   product
D.   intermediate
Question #33
Baker's yeasts ferment sugar for what purpose?
A.   to prepare the cell for aerobic respiration
B.   to convert sugar into starch
C.   to release energy needed to make ATP
D.   to produce carbon dioxide & alcohol
Question #34
Which was the most nonpolar pigment?
A.   yellow carotene
B.   yellow green chlorophyll b
C.   purple anthocyanin
D.   grass green chlorophyll a
Question #35
Hot ___________ bath was used to extract (remove) the green pigment from the leaf.
A.   alcohol
B.   iodine
C.   acetone & petroleum ether
D.   water
Question #36
Which observed evidence was used to support the hypothesis that chlorophyll is needed to produce starch?
A.   Bubbles showed up after soaking the leaf in iodine solution.
B.   The dark purple areas (after iodine was added) were located in what used to be in the white edges in the leaf.
C.   Coagulation occurred in the center of the leaf.
D.   The dark purple areas (after iodine was added) were located in what used to be the green areas in the leaf.
Question #37
The bubbles released from the test tube containing liver & H2O2 were the result of the ____________________.
A.   enzymes getting denatured
B.   release of O2 from the reaction
C.   boiling of living tissues
D.   H2O2 evaporating
Question #38
Use the given data to answer the next question: Rf of A = 0.38 Rf of B = 0.45 Rf of C = 0.80 Rf of D = 0.98 Which was the most polar pigment?
A.   A
B.   D
C.   C
D.   B
Question #39
Consider the experiment that tested the hypothesis that enzyme catalyzes chemical reactions. A tube with milk by itself and tube with milk with rennin (rennet) were set up. What was the independent variable?
A.   presence/absence of rennin (rennet)
B.   presence/absence of milk protein
C.   color of the solution inside the test tubes
D.   coagulation
Question #40
The inflated balloon & foamy suspension from the bottle containing yeast, sugar & water indicated that _______________is occurring.
A.   fermentation
B.   signal transduction
C.   photosynthesis
D.   aerobic respiration
Question #41
Identify “pouch-shaped” region on the surface of an enzyme where substrates dock and eventually get converted into products.
A.   Carbon dioxide and alcohol
B.   metabolism
C.   lactic acid
D.   active site
Question #42
Identify chemical reactions in cells required by organisms to assimilate energy to be used for growth and reproduction
A.   Carbon dioxide and alcohol
B.   metabolism
C.   active site
D.   lactic acid
Question #43
Identify fermentation product when human cells do not get sufficient oxygen gas
A.   Carbon dioxide and alcohol
B.   active site
C.   metabolism
D.   lactic acid
Question #44
Identify two molecules produced when Baker's yeast cells are grown under anaerobic conditions
A.   Carbon dioxide and alcohol
B.   metabolism
C.   active site
D.   lactic acid
Question #45
Identify the enzyme that covalently bonds inorganic phosphate to ADP from energy released when H+ diffuses back into mitochondrial matrix.
A.   ATP synthase
B.   phosphatase 
C.   catalase
D.   rubisco
Question #46
Identify the enzyme that breaks down hydrogen peroxide into water & oxygen gas.
A.   rubisco
B.   caspases
C.   catalase
D.   phosphatase 
Question #47
Identify the enzyme that fixes ("attaches") carbon dioxide to ribulose bisphosphate (RuBP) to initiate the Calvin cycle.
A.   ATP synthase
B.   rubisco
C.   phosphatase 
D.   caspases
Question #48
Identify the enzyme that remove phosphate to deactivate relay proteins during signal transduction.
A.   caspases
B.   phosphatase 
C.   ATP synthase
D.   catalase
Question #49
Identify the enzyme that is responsible for genetically programmed & cell-regulated suicide.
A.   ATP synthase
B.   catalase
C.   caspases
D.   rubisco
Question #50
Describe a specific example of a signal molecule communicating with a target cell by the name of the signal molecule.
A.   tyrosine kinase receptor
B.   insulin
C.   uptake of glucose inside the cell
Question #51
Describe a specific example of a signal molecule communicating with a target cell by type of receptor that matches it, if known.
A.   insulin
B.   tyrosine kinase receptor
C.   uptake of glucose inside the cell
Question #52
Describe a specific example of a signal molecule communicating with a target cell by type of response of the target cell.
A.   tyrosine kinase receptor
B.   insulin
C.   uptake of glucose inside the cell

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