Exam 2

The overall reaction for photosynthesis is: 3CO2 + 3 H2O + Energy C3H6O3 + 3 O2. Which of the following statements describes what happens to electrons from the original CO2 in this reaction? 1. Electrons from CO2 are pulled closer to carbon, and carbon is reduced. 2. Electrons from CO2 are pulled closer to oxygen, and oxygen is reduced. 3. Electrons from CO2 are pulled closer to hydrogen, and hydrogen is oxidized. 4. Electrons from CO2 are pulled further away from carbon, and carbon is oxidized.

1. Electrons from CO2 are pulled closer to carbon, and carbon is reduced.

Why is ATP an important molecule in metabolism? 1. It provides energy coupling between exergonic and endergonic reactions. 2. Its terminal phosphate group contains a strong covalent bond that, when hydrolyzed, releases free energy. 3. Its hydrolysis provides an input of free energy for exergonic reactions. 4. It is one of the four building blocks for DNA synthesis

1. It provides energy coupling between exergonic and endergonic reactions.

The products of Photosystem I and Photosystem II are, respectively, 1. NADPH, ATP, and O2. 2. NADH, ATP, and CO2. 3. ATP, CO2, and NADPH 4. RuBP and a simple sugar. 5. a simple sugar and RuBP

1. NADPH, ATP, and O2

Mitochondria and chloroplasts are double-membrane organelles that have both an inner and an outer compartment. How might the presence of two compartments contribute to the function of these organelles? 1. The two compartments permit different, but complementary functions, to be accomplished in these organelles. 2. The double-membrane feature is not important, it's just a leftover characteristic of cellular evolution. 3. The double-membrane feature assures that ribosomes remain separated from the functional compartment of mitochondria and chloroplasts. 4. The two compartments might provide extra protection against dehydration.

1. The two compartments permit different, but complementary functions, to be accomplished in these organelles.

In the cells of some organisms, mitosis occurs without cytokinesis. This results in 1. cells with more than one nucleus. 2. cells that are unusually small. 3. cells lacking nuclei. 4. cell cycles lacking an S phase.

1. cells with more than one nucleus

A chemical reaction that has a negative ΔG is best described as non-spontaneous. 1. exergonic. 2. endergonic. 3. entropic.

1. exergonic

The phases of the Calvin cycle, in the correct sequence, are 1. fixation of CO2, reduction of carbon, regeneration of RuBP. 2. fixation of CO2, reduction of carbon, regeneration of oxaloacetate. 3. regeneration of RuBP, fixation of CO2, oxidation of carbon. 4. fixation of CO2, oxidation of carbon, regeneration of RuBP.

1. fixation of CO2, reduction of carbon, regeneration of RuBP.

Many reactions used by cells involve oxidation and reduction. Oxidation involves 1. loss of electrons. 2. loss of hydrogen ions. 3. gain of hydrogen ions. 4. gain of electrons.

1. loss of electrons

If a cell has accumulated too much DNA damage, it is unlikely to 1. pass the G2 checkpoint. 2. activate DNA repair mechanisms. 3. enter G1 from mitosis. 4. synthesize RNA.

1. pass the G2 checkpoint

In addition to pyruvate, which of the following are the end products of glycolysis? 1. 6 CO2 and 12 H2O 2. 2 NADH and 2 ATP 3. 6 NADH and 2 FADH2 4. 29 ATP and 12 H2O

2. 2 NADH and 2 ATP

Which answer correctly associates a phase of mitosis with what happens to sister chromatids during that phase? 1. Prophase: Chromosomes are replicated. 2. Anaphase: Sister chromatids separate. 3. Prometaphase: Chromosomes complete their migration to the middle of the cell. 4. Telophase: Chromosomes condense.

2. Anaphase: sister chromatids separate.

Which structure—function pair is mismatched? 1. nucleolus—production of ribosomal subunits 2. lysosome—energy production 3. ribosome—protein synthesis 4. vacuoles - storage

2. Lysosome- energy production

How is plant cell cytokinesis different from animal cell cytokinesis? 1. The contractile filaments found in plant cells are structures composed of carbohydrates; the cleavage furrow in animal cells is composed of contractile phospholipids. 2. Plant cells deposit vesicles containing cell-wall building blocks in the cell center; animal cells form a cleavage furrow. 3. The structural proteins of plant cells separate the two cells; in animal cells, a cell membrane separates the two daughter cells. 4. Plant cells divide after metaphase but before anaphase; animal cells divide after anaphase.

2. Plant cells deposit vesicles containing cell-wall building blocks in the cell center; animal cells form a cleavage furrow.

Which answer correctly associates a phase of mitosis with what happens during that phase? 1. Cytokinesis: formation of the cell plate. 2. Prometaphase: the nuclear membrane disintegrates 3. Prophase: the nuclear membrane disintegrates 4. Telophase: the nuclear membrane disintegrates 5. Metaphase: sister chromatids are separated

2. Prometaphase: the nuclear membrane disintegrates

Why are fermentation reactions important for cells? 1. They produce alcohol, which enhances the permeability of their mitochondrial membranes to proton translocation. 2. They regenerate NAD+ so that glycolysis can continue to operate. 3. They allow the cell to conserve oxygen for the citric acid cycle. 4. They generate oxygen.

2. They regenerate NAD+ so that glycolysis can continue to operate.

Why are there several structurally different pigments in the reaction centers of photosystems? 1. Excited electrons must pass through several pigments before they can be transferred to electron acceptors of the electron transport chain. 2. This arrangement enables the plant to absorb light energy of a variety of wavelengths. 3. They enable the plant to absorb more photons from light energy, all of which are at the same wavelength. 4. They enable the reaction center to excite electrons to a higher energy level.

2. This arrangement enables the plant to absorb light energy of a variety of wavelengths

The oxygen consumed during cellular respiration is directly involved in which process or event? 1. glycolysis 2. accepting electrons at the end of the electron transport chain 3. the citric acid cycle 4. the oxidation of pyruvate to acetyl CoA 5. the phosphorylation of ADP to form ATP

2. accepting electrons at the end of the electron transport chain

A competitive inhibitor decreases the rate of an enzyme reaction by 1. changing the shape of the enzyme's active site. 2. binding at the active site of the enzyme and blocking substrate binding. 3. changing the overall free-energy of the reaction. 4. acting as a coenzyme for the reaction and holding high energy electrons.

2. binding at the active site of the enzyme and blocking substrate binding

Which of the following organelles does not have at least one membrane? 1. nucleus 2. cytoskeleton 3. mitochondria 4. endoplasmic reticulum

2. cytoskeleton

Enzymes 1. make the reactions more exergonic. 2. lower the activation energy of reactions. 3. reduce the rate of reverse reactions. 4. make the rate of a reaction independent of substrate concentrations

2. lower the activation energy of reactions

Which compounds below represent the net output for the complete breakdown of one molecule of glucose? 1. 6 CO2, 12 H2O, and ~29 ATP 2. 2 pyruvate, 2 ATP, and 2 NADH 3. 2 ATP, 4 CO2, 6 NADH, and 2 FADH2 4. 6 CO2, 12 H2O, 8 NADH, 2 FADH2, and 4 ATP

3. 2 ATP, 4 CO2, 6 NADH, and 2 FADH2

Which of the following combinations of products would result from two acetyl-CoA molecules entering the citric acid cycle? 1. 1 ATP, 2 CO2, 3 NADH, and 1 FADH2 2. 1 ATP, 2 CO2, 6 NADH, and 1 FADH2 3. 2 ATP, 4 CO2, 6 NADH, and 2 FADH2 4. 2 ATP, 6 CO2, 9 NADH, and 2 FADH2

3. 2 ATP, 4 CO2, 6 NADH, and 2 FADH2

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle? 1. CO2 and glucose 2. H2O and O2 3. ATP and NADPH 4. ATP and NADH

3. ATP and NADPH

What do substrate-level phosphorylation and oxidative phosphorylation have in common? 1. Both processes produce NADPH from NADH and Pi 2. Both processes occur in the matrix of mitochondria. 3. Both processes produce ATP from ADP and Pi. 4. Both processes occur under the action of ATP synthase.

3. Both processes produce ATP from ADP and Pi

You collect data on the effect of pH on the function of the enzyme catalase in human cells. Which of the following graphs would you expect? Note that the y axis represents increasing enzyme function, and the x axis represents increasing pH, starting from pH 3.0. 1. A 2. B 3. C 4. D

3. C

Which of the following is a statement of the first law of thermodynamics? 1. The entropy of the universe is decreasing. 2. The entropy of the universe is constant 3. Energy cannot be created or destroyed. 4. Kinetic energy is stored energy that results from the specific arrangement of matter. 5. Energy cannot be transferred or transformed.

3. Energy cannot be created or destroyed

Which of these statements describes a major difference between prokaryotic and eukaryotic cells? 1. Prokaryotes are a more homogenous group of organisms than eukaryotes, which include protozoa, plants, and animals. 2. Prokaryotes, not eukaryotes, have cell walls. 3. Eukaryotic cells tend to have much more extensive inner membrane systems and larger numbers of intracellular organelles than do prokaryotes. 4. Prokaryotes are unable to carry out protein synthesis, because they have no RER.

3. Eukaryotic cells tend to have much more extensive inner membrane systems and larger numbers of intracellular organelles than do prokaryotes.

Which of the following statements about NAD+ is TRUE? 1. NAD+ has more chemical energy than NADH. 2. NAD+ can donate electrons for use in oxidative phosphorylation. 3. NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. 4. In the absence of NAD+, glycolysis can still function. 5. NAD+ is oxidized to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.

3. NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.

Phosphofructokinase is an enzyme that is part of the glycolysis pathway. This enzyme catalyzes the conversion of fructose 6-phosphate to 1,6-bisphosphate. The rate of this reaction slows when ATP levels in the cell increase. This is an example of 1. feedforward activation. 2. competitive inhibition. 3. feedback inhibition. 4. enzyme specificity.

3. feedback inhibition

The active site of an enzyme is the region that 1. binds allosteric regulators of the enzyme. 2. binds noncompetitive inhibitors of the enzyme. 3. is involved in the catalytic reaction of the enzyme. 4. is inhibited by the presence of a coenzyme or a cofactor.

3. is involved in the catalytic reaction of the enzyme

Movement of the chromosomes during anaphase would be most affected by a drug that prevents 1. nuclear envelope breakdown. 2. cell-wall formation. 3. shortening of microtubules. 4. formation of a cleavage furrow.

3. shortening of microtubules

In mitochondria, chemiosmosis moves protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis moves protons from the 1. stroma to photosystem II. 2. matrix to the stroma. 3. stroma to the thylakoid space (lumen). 4. intermembrane space to the matrix. 5. thylakoid space to the stroma.

3. stroma to the thylakoid space (lumen)

What is the purpose of cellular respiration? 1. to generate oxygen 2. to supply the cell with fixed carbon 3. to produce ATP (adenosine triphosphate) 4. to utilize glucose

3. to produce ATP (adenosine triphosphate)

What is the first event that follows absorption of a photon by chlorophyll in the antenna complex of a chloroplast? 1. ATP is synthesized from the energy absorbed. 2. A carboxylation reaction of the Calvin cycle occurs. 3. Electrons are stripped from NADPH. 4. An electron moves to a higher energy level.

4. An electron moves to a higher energy level.

Why is glycolysis described as having an energy investment phase and an energy production phase? 1. It both splits molecules and assembles molecules. 2. It uses glucose and generates pyruvate. 3. It shifts molecules from cytosol to mitochondrion. 4. It needs some ATP to start but then yields a net increase in ATP.

4. It needs some ATP to start but then yields a net increase in ATP.

A newly developed insecticide compound removes high-energy electrons from FADH2 and NADH before they are delivered to the electron transport chain. Why does this kill insects? 1. Glycolysis reactions are blocked. 2. The citric acid cycle cannot proceed. 3. Fermentation pathways will be switched on, supplying insufficient ATP to maintain the insect. 4. The Electron Transport Chain (ETC) cannot establish a proton gradient to drive oxidative phosphorylation.

4. The Electron Transport Chain (ETC) cannot establish a proton gradient to drive oxidative phosphorylation.

Which region of a mitochondrion is specifically used to create the Proton Motive Force used to drive oxidative phosphorylation? 1. matrix 2. inner membrane 3. outer membrane 4. intermembrane space

4. intermembrane space

If the smooth endoplasmic reticulum of a cell became dysfunctional, the ability of the cell to perform which of the following processes would be compromised? 1. making ATP 2. replicating DNA 3. controlling osmotic pressure 4. producing lipids

4. producing lipids

Which of the following does NOT occur during mitosis? 1. separation of the centrosomes 2. separation of sister chromatids 3. spindle formation 4. replication of the DNA 5. All of these processes occur during mitosis.

4. replication of the DNA

In which of the following organelles or structures would you expect to find proteins? 1. Nucleus and nucleolus 2. Mitochondria 3. Plasma membrane 4. a and b only 5. All of the above.

5. All of the above

Which compound in the following equation, is reduced? BH2 + NAD+ --> B + NADH + H+ 1. BH2 2. NAD+ 3. B 4. NADH

NAD+