BIOL 150 Unit 3 Questions

Autotrophs typically obtain their carbon from:
a. ATP.
b.CH4.
c.CH3OH.
d.C6H12O6.
e.CO2.

Animals such as humans would be classified as:
a. photoautotrophs.
b.chemoheterotrophs.
c.chemoautotrophs.
d.photoheterotrophs.

The sum of all chemical reactions in a cell is referred to as ____________.

Which one of the following is an example of potential energy?
a.heat
b.wind
c.an electrochemical gradient
d.light
e.a moving muscle

Which of the following is a component of a molecule of ATP? Select all correct choices.
a.three phosphate groups
b.three phosphate groups and ribose
c.ribose
d.adenine

ATP is chemically related most closely to which of the following?
a.glucose
b.tryptophan amino acid
c.testosterone
d.phospholipid
e.thymine nucleotide

Which of the following statements reflects the second law of thermodynamics?
a.The entropy of the starting materials for a reaction will always be greater than the entropy of the products
b.The entropy of the products of a reaction will always be greater than the entropy of the starting materials.
c.The amount of useable energy resulting from a reaction will always be less than the total energy available in the starting materials.
d.The energy of the starting materials for a reaction will equal the sum of energies of the products plus energy released as heat and disorder.

Based on what you know of ATP’s chemistry, which of the following might be most likely to have possible similar uses in energy-management processes?
a. phospholipids
b.potassium ions (K+)
c.lysine (amino acid)
d.guanine nucleotide
e.steroids

Suppose you use a match to ignite a sheet of paper from your notebook, and allow the fire to continue until the burning stops. If you could measure all the energy in the resulting combustion products, and all the energy in the heat released (including whatever increase in disorder has occurred), would you predict this amount to be more than, less than, or the same amount as the amount of potential energy in the starting sheet of paper? (You should ignore the activation energy provided by the match to light the paper.)

a.more energy than the paper
b.less energy than the paper
c.the same energy as the paper

Which of the following reactions would you predict could be coupled to ATP hydrolysis to ADP + Pi to make it energetically favorable, or spontaneous?

a.glutamic acid + NH3 → glutamine, ∆G +3.4 kcal/mol
b.creatine phosphate + H2O → creatine + Pi, ∆G -10.3 kcal/mol
c.glucose 1-phosphate + H2O → glucose + Pi, ∆G -5.0 kcal/mol
d.phosphoenolpyruvate + H2O → pyruvate + Pi, ∆G -14.8 kcal/mol
e.glucose 6-phosphate + H2O → glucose + Pi, ∆G -3.3 kcal/mol

Autotrophs typically obtain their carbon from:

a.CH4.
b.ATP.
c.CH3OH.
d.C6H12O6.
e.CO2.

Which of the following is the most precise description of the role of enzymes in catalyzing biochemical reactions?

a.Enzymes decrease the ∆G of the reactions making them proceed rapidly.
b.Enzymes cut hard to break bonds allowing the reaction to proceed.
c.Enzymes increase the ∆G of the reactions making them proceed rapidly.
d.Enzymes stabilize the transition state and decrease its free energy.
e.Enzymes provide the necessary activation energy to overcome the transition state.

Which of the following reactions is most likely to be exergonic?

a.the replication of DNA from free nucleotides
b.the digestion of protein from food into amino acids
c.the synthesis of a phospholipid from glycerol and fatty acids
d.the formation of cellulose from individual glucose molecules

Which of the following statements is NOT one of the laws of thermodynamics?

a.The energy available to do work decreases as energy is transferred from one form to another.
b.None of the statements in these choices is a law of thermodynamics.
c.The amount of energy in the universe is constant.
d.All cells arise from pre-existing cells.

The amount of energy in a system that cannot be used to perform work is referred to as ____________.

The highest free energy of a reaction is found in the ____________(s) of that reaction.

a.substrate
b.transition state
c.product

True or False: an anabolic reaction decreases entropy within the system because the reaction results in a more ordered macromolecule.
a.true
b.false

Which of the following is a net product of glycolysis? Select all correct choices.

a.2 NADH
b.2 ATP
c.2 pyruvate

In most living cells, which one of the following is not a product of cellular respiration?

a.All of these choices are products of cellular respiration in most living cells.
b.ATP
c.carbon dioxide
d.water
e.oxygen

The loss of electrons is referred to as ____________.

In eukaryotic cells, the oxidation of pyruvate occurs in:

a.the cytoplasm.
b.the endoplasmic reticulum.
c.the matrix of the mitochondria.
d.vacuoles.
e.the nucleus.

In eukaryotic cells, glycolysis occurs in:

a.vacuoles.
b.the endoplasmic reticulum.
c.the cytoplasm.
d.the matrix of the mitochondria.
e.the nucleus.

True or False: a cellular reaction with a ΔG of 8.5 kcal/mol could be effectively coupled to the hydrolysis of a single molecule of ATP.

a.true
b.false

Which of the following is the most precise description of the role of enzymes in catalyzing biochemical reactions?

a.Enzymes increase the ∆G of the reactions making them proceed rapidly.
b.Enzymes provide the necessary activation energy to overcome the transition state.
c.Enzymes cut hard to break bonds allowing the reaction to proceed.
d.Enzymes stabilize the transition state and decrease its free energy.
e.Enzymes decrease the ∆G of the reactions making them proceed rapidly.

Example Exam Question: Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate?

a.citrate
b.acetyl CoA
c.glyceraldehydes-3-phosphate
d.oxaloacetate
e.lactate

______ allow reactions to proceed at suitable rates at moderate temperatures by reducing the activation energy barrier

a.Carbohydrates
b.Enzymes
c.Entropy
d.Gibbs Free Energy
e.Substrates

In which of the following molecules are the electrons of the atoms shared in covalent bonds at the furthest distance from the nucleus?

a.carbon dioxide
b.glucose
c.water

Which of these summarizes the overall reactions of cellular respiration?

a.C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy
b.6 CO2 + 6 O2 → C6H12O6 + 6 H2O
c.C6H12O6 + 6 O2 + energy → 6 CO2 + 12 H2O
d.6 CO2 + 6 H2O + energy → C6H12O6 + 6 O2
e.H2O → 2 H+ + 1/2 O2 + 2e-

Which of the following describes ATP hydrolysis? Select all correct choices.

a.spontaneous
b.often coupled to a reaction that has a positive ΔG
c.exergonic

Example Exam Question: In the final step of alcohol fermentation, NADH is oxidized to NAD+ and ________ is reduced to _______

a.pyruvate/ethanol
b.acetaldehyde/ethanol
c.lactate/pyruvate
d.acetate/ethanol
e.pyruvate/lactate

You are trying to find the best maximum source of energy for an organism. Which of the following compounds would you choose?
a.pyruvate
b.ATP
c.oxygen
d.NADH
e.glucose

Photorespiration results in:
a.the loss of CO2.
b.All of these choices are correct.
c.the consumption of ATP and the loss of CO2.
d.the inactivation of rubisco.
e.the consumption of ATP.

During photosynthesis in plants and algae, ____________ is oxidized and ____________ is reduced.

a.O2; CO2
b.NADPH; ATP
c.CO2; H2O
d.H2O; O2
e.H2O; CO2

The reducing agent during the Calvin cycle is:
a.oxygen.
b.ATP.
c.FADH2.
d.NADPH.
e.NADH

In plants and algae, ____________ is the source of the electrons needed for photosynthesis.

a.CO2
b.H2O
c.H+
d.NADPH
e.O2

True or false: Eukaryotes conduct all of the photosynthesis that occurs in the ocean.
a.true
b.false

Which regulatory mechanism is activated when the overall energy availability of a cell is high?

a.ATP inhibits phosphofructokinase 1.
b.AMP up-regulates phosphofructokinase 1.
c.ADP up-regulates phosphofructokinase 1.
d.Citrate inhibits phosphofructokinase 1.

When fats are used as an energy source, the fatty acids are broken down to acetyl-CoA. That means that fats bypass the reactions of ____________ and enter the respiratory pathway at ____________.

a.glycolysis; the citric acid cycle
b.fermentation; glycolysis
c.the citric acid cycle; oxidative phosphorylation
d.the citric acid cycle; glycolysis
e.oxidative phosphorylation; fermentation

Each round of the citric acid cycle begins when the 4-carbon molecule oxaloacetate is converted to the 6-carbon molecule citrate. As the cycle progresses, two carbons are eliminated to regenerate the oxaloacetate. The added carbon is supplied by ____________ and the two eliminated carbons are released as ____________.

a.ATP; acetyl-CoA
b.acetyl-CoA; CO2
c.CO2; acetyl-CoA
d.CO2; NADH
e.CO2; pyruvate

The breakdown of one glucose molecule during glycolysis results in 2 molecules of pyruvate, which are then oxidized to 2 molecules of acetyl-CoA, and these, in turn, are substrates for the citric acid cycle. If all three fatty acids of a triacylglycerol molecule (a fat molecule) are palmitic acid (C16, having 16 carbons), how many acetyl-CoA molecules would result from beta-oxidation of all of these fatty acids?

a.32
b.16
c.8
d.24
e.4

Which regulatory mechanism is important in keeping glycolysis and the citric acid cycle in relative balance to each other?

a.Citrate inhibits phosphofructokinase 1.
b.ATP inhibits phosphofructokinase 1.
c.AMP inhibits phosphofructokinase 1.
d.ADP up-regulates phosphofructokinase 1.

In human cells such as muscle tissue, the product of anaerobic respiration is:

a.lactic acid.
b.FADH2.
c.acetic acid.
d.ethanol.
e.pyruvate.

During glycolysis and the TCA cycle, NADH2 is produced from NAD. Is NAD reduced or oxidized to form NADH2?
a.NAD is reduced
b.NAD is oxidized
c.NAD is metabolized

Very low concentrations of detergent make membranes leaky to small molecules and ions without damaging proteins. In isolated mitochondria exposed to detergent, the molecules of the electron transport chain and of ATP synthase remain intact. Do you expect ATP synthesis to continue in the presence of low concentrations of detergent?

a.Yes, because all enzymes and electron carriers are functional.
b.No, because leaky membranes inhibit glycolysis.
c.No, because with a leaky membrane, H+ gradient cannot be maintained.
d.No, because leaky membranes do not allow NADH and FADH2 to donate their electrons to the electron transport chain.

What happens to pyruvate during the process of fermentation?

a.It is oxidized to ethanol.
b.It is converted to acetyl Co-A.
c.It gets converted to pyruvic acid.
d.It is reduced to ethanol.
e.It is oxidized to lactic acid.

Animals breathe in air containing oxygen and breathe out air with less oxygen. The consumed oxygen is used:

a.in the glycolysis pathway.
b.in the conversion of pyruvate to acetyl Co-A.
c.in photosynthesis.
d.as an electron acceptor in the respiratory electron transport chain.
e.in the Krebs cycle.

In eukaryotic cells, the oxidation of pyruvate occurs in:
a.the matrix of the mitochondria.
b.the cytoplasm.
c.the endoplasmic reticulum.
d.vacuoles.
e.the nucleus.

The citric acid cycle begins when acetyl-CoA combines with ____________ to form ____________.

a.oxaloacetate; citrate
b.pyruvate; citrate
c.citrate; cis-aconitate
d.oxaloacetate; malate
e.malate; oxaloacetate

Following the citric acid cycle but before the electron transport chain and oxidative phosphorylation, most of the energy from the original glucose molecule is found in ____________.

a.ATP
b.NADH
c.pyruvate
d.acetyl-CoA
e.CO2

Atractyloside is a poison that inhibits the transport of ADP from the cytosol across the mitochondrial membranes and into the mitochondrial matrix. The direct effect of this drug is to stop ATP synthesis because:

a.it prevents electron transfer from NADH to complex I.
b.ADP is a necessary substrate for the reaction catalyzed by ATP synthase.
c.it prevents electron transfer to O2.
d.it prevents proton pumping across the inner mitochondrial membrane.

Which of the following is a net product of the citric acid cycle for each molecule of pyruvate generated in glycolysis? Select all correct choices.

a.3 NADH
b.1 FADH2
c.1 ATP

As adults, insulin signaling through its receptor kinase enables virtually every cell in our body to transport glucose across the plasma membrane into the cytosol. Use the following five terms to complete the sentences below. Terms (1-4) may be used once, more than once or not at all.

1. receptor binding
2. receptor activation
3. signal transduction and amplification
4. response
5. termination

Autophosphorlyation of transmembrane proteins caused by insulin association with those proteins is an example of ____________.
____________ occurs when the proteins that are phosphorylated after insulin associates with the cell-surface protein become dephosphorylated.
The noncovalent association of insulin with specific proteins on the surface of a cell is an example of ____________.
Activated proteins in the nucleus causing transcription (and eventually translation in the cytosol) of proteins needed for cell division is an example of ____________.
____________ occurs when the insulin receptors phosphorylate each other causing other proteins in the cytoplasm to bind to them, including a protein called insulin-receptor substrate 1 (or IRS-1).
____________ occurs when the phosphorylated cytosolic protein IRS-1 binds to other cytosolic proteins to activate them, which in turn bind to others to activate them.
One consequence of IRS-1 stimulation is the exchange of GDP for GTP in Ras, which is an example of ____________.
____________ occurs when the GTP bound to Ras is hydrolyzed to GDP.
One consequence of IRS-1 stimulation is the uptake of glucose by the cell, which is an example of ____________.

a.1, 3, 3, 4, 2, 1, 3, 4, 1
b.4, 3, 1, 1, 2, 4, 3, 1, 3
c.2, 5, 1, 4, 3, 3, 3, 5, 4
d.2, 1, 4, 4, 5, 1, 2, 2, 1

A chemical that binds to a cell to cause its activity to change is an example of which of the following elements of cellular communication?

a.None of these choices are correct.
b.a receptor molecule
c.a signaling cell
d.a responding cell
e.a signaling molecule

A cell that responds to an environmental condition by the release of a chemical is an example of which of the following elements of cellular communication?

a.a signaling cell
b.a responding cell
c.a receptor molecule
d.None of these choices are correct.
e.a signaling molecule

A new experimental pesticide is being tested by a large agricultural chemical company. An unfortunate side effect in plants treated with this new product is a decrease in ATP production in the chloroplasts. (Interestingly, production of ATP in the mitochondria is unaffected.) Given this observation, which of the following would you expect to be DIRECTLY affected by the new pesticide?

a.the rate of photorespiration
b.the carboxylation of RuBP by rubisco
c.the oxidation of RuBP by rubisco
d.the transport of electrons along the photosynthetic electron transport chain

A protein on a cell surface that binds to a signaling molecule is an example of which of the following elements of cellular communication?

a.a receptor molecule
b.a signaling cell
c.a responding cell
d.None of these choices are correct.
e.a signaling molecule

Choose from the following terms to fill in the blanks in the correct order.

1. ligand
2. signaling cell
3. receptor
4. responding cell

In communication between cells, the ____________ produces the signaling molecule, also known as the ____________; the ____________ produces the ____________, to which the signaling molecule binds.

a.4, 3, 2, 1
b.2, 3, 1, 4
c.1, 2, 3, 4
d.2, 1, 4, 3

In the chloroplast, cytochrome b6f is an important complex in the photosynthetic electron transport chain because it accepts electrons from photosystem II and donates them to photosystem I. Another vital function of cytochrome b6f is that during its reduction-oxidation cycle it pumps ____________ from the ____________.

a.hydrogen ions; stroma into the thylakoid
b.electrons; thylakoid into the stroma
c.hydrogen ions; thylakoid into the stroma
d.electrons; stroma into the thylakoid

The pH in the stroma of the chloroplast should be ____________ compared to the thylakoids due to the ____________.

a.higher; lower concentration of hydrogen ions in the thylakoid
b.higher; higher concentration of hydrogen ions in the thylakoid
c.lower; lower concentration of hydrogen ions in the thylakoid
d.lower; higher concentration of hydrogen ions in the thylakoid

Photorespiration in chloroplasts differs from cellular respiration in mitochondria in that ____________.

a.NADH supplies high-energy electrons in mitochondrial respiration, whereas RuBP supplies the electrons necessary for photorespiration
b.ATP is required for photorespiration but is a product of mitochondrial respiration
c.carbon dioxide is produced in mitochondrial respiration, and oxygen is produced in photorespiration
d.photorespiration supplies plant cells with ATP. Mitochondrial respiration supplies animal cells with ATP.

Predict which of the following would happen if a plant was exposed to a toxin that made the thylakoid membranes permeable to hydrogen ions.

a.The oxidation and reduction of the protein complexes in the electron transport would be prevented.
b.The hydrogen ion gradient across thylakoid membrane would be eliminated.
c.The hydrogen ions necessary to generate NADPH from NADP+ would no longer be present.
d.A reversal of the hydrogen ion gradient across the thylakoid membrane would result in a higher pH in the thylakoid lumen than in the surrounding stoma.

A new experimental pesticide is being tested by a large agricultural chemical company. An unfortunate side effect in plants treated with this new product is the partial inhibition of ferredoxin-NADP+ reductase. Given this observation, which of the following would you expect to observe in the photosynthetic cells of these plants?

a.decreased rate of cyclic electron transport
b.decreased levels of ATP in the chloroplast
c.decreased rate of triose phosphate production
d.decreased levels of NADP+ in the chloroplast

Which of the following is NOT part of the general response of cells during cellular communication?

a.A cell-surface receptor molecule becomes activated by binding to its molecular signal.
b.A receptor on the outside of the cell binds to a specific signal molecule that it is designed to capture.
c.The cell automatically returns to its normal activities after the signal has exerted its effect.
d.The signal is carried and amplified inside the cell by binding to a series of specific proteins, affecting cellular activities according to the type of signal involved.
e.An activated cell-surface receptor transfers the signal to the interior of the cell.

A new experimental pesticide is being tested by a large agricultural chemical company. An unfortunate side effect in plants treated with this new product is a decrease in NADPH production in the chloroplasts. (Interestingly, reduction of NAD+ to NADH in the mitochondria is unaffected.) Given this observation, which of the following would you expect to observe in the chloroplasts of these plants?

a.a decrease in 3-phosphoglycerate levels and an increase in RuBP
b.an increase in 3-phosphoglycerate production and an increase in RuBP
c.an increase in glyceraldehyde-3-phosphate production
d.an increase in 3-phosphoglycerate levels and a decrease in RuBP production

Normally, the xanthophylls present in the thylakoid membrane are associated mainly with photosystem II. If a mutation occurred that caused xanthophylls to be randomly distributed in the thylakoid membrane, which of the following would you predict would happen?

a.NADPH production would increase under conditions of intense light.
b.Levels of reactive oxygen species in the thylakoid lumen would drop dramatically.
c.The frequency of nonspecific oxidation of molecules in the cell would increase.
d.The rate of cyclic electron transport would increase.

Both starch and sucrose are assembled from glucose synthesized in the cholorplast. But, when you tap a sugar maple tree, you will find sucrose but not starch. Why is sugar transported as sucrose and not as starch?

a.most starch is used to assemble cell walls, so it cannot be transported in the plant.
b.starch contains less potential energy than water so the plant transports sucrose.
c.starch is not soluble in water so it cannot be transported in the plant

In plants, the ultimate electron donor in photosynthesis is ___________.

Photosynthesis is the pathway used to synthesize carbohydrates from:

a.sunlight.
b.sunlight and carbon dioxide.
c.sunlight, carbon dioxide, and oxygen.
d.oxygen.
e.carbon dioxide.

During photosynthesis, ___________ is reduced to ___________.

a.carbon dioxide; glucose
b.carbon dioxide; oxygen
c.water; carbon dioxide
d.glucose; oxygen
e.oxygen; water

True or False: not all photosynthetic organisms are plants, but one thing they all have in common is that they can only be found within a narrow temperature and moisture range.

a.False
b.True

True or False: like mitochondria, the inner membranes of chloroplasts are highly convoluted so as to greatly increase surface area.

a.true
b.false