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

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