University of Michigan
2 MAXE · 171 OIB
★ ★
M College of Literature, Science & the Arts — Department of Biology
EST. 1817
ARTES · SCIENTIA · VERITAS
Bio 171 Exam 2
C E L LU L A R R E S P I RAT I O N · P H OTO SY N T H E S I S · C E L L S I G N A L I N G · M I TO S I S · M E I O S I S
· G E N E T I CS
INSTITUTION University of Michigan PROGRAM Bachelor of Science — Biology
COURSE CODE BIO 171 COURSE TITLE Introduction to Molecular &
Cellular Biology
ACADEMIC YEAR EXAM TITLE Bio 171 Exam 2
TOTAL QUESTIONS 97 Questions FORMAT Multiple Choice — Select the
Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This examination covers cellular respiration, photosynthesis, cell signaling, mitosis, meiosis, genetics,
and bioenergetics.
▸ Questions address glycolysis, the citric acid cycle, oxidative phosphorylation, the Calvin cycle, receptor
signaling, the cell cycle, and Mendelian genetics.
▸ Correct answers and explanatory rationales appear below each question for review purposes.
▸ All content reflects standard introductory biology curriculum for BIO 171 at the University of Michigan.
, SECTION I — CELLULAR RESPIRATION, PHOTOSYNTHESIS
Questions 1 – 97
& GENETICS
1. Why are ion channels necessary to transport ions into or out of a cell?
A. Ions are too large to cross the membrane by any means
B. Ions are charged particles and cannot diffuse through the hydrophobic interior of the
membrane
C. Ions require active transport pumps exclusively for all movement
D. Ions are soluble only in the lipid bilayer without assistance
CORRECT ANSWER B — Ions are charged particles and cannot diffuse through the hydrophobic
interior of the membrane
RATIONALE The plasma membrane's interior is composed of hydrophobic fatty acid tails that
repel charged particles. Ions such as Na+, K+, Ca2+, and Cl- are charged and
therefore cannot pass through the nonpolar lipid bilayer by simple diffusion. Ion
channels provide hydrophilic pores that allow specific ions to cross the
membrane down their electrochemical gradients. This is a fundamental principle
of membrane transport.
2. What compound receives electrons from NADH in the electron transport chain?
A. Carbon dioxide
B. Oxygen
C. Glucose
D. ATP
CORRECT ANSWER B — Oxygen
RATIONALE Oxygen is the final electron acceptor in the electron transport chain. NADH
donates electrons to Complex I, and they flow through the chain of protein
complexes, ultimately being transferred to molecular oxygen (O2), which
combines with hydrogen ions to form water. This is why oxygen is essential for
aerobic respiration.
,3. At which stage of mitosis do the chromosomes become visible under a light microscope?
A. Interphase
B. Prophase
C. Metaphase
D. Anaphase
CORRECT ANSWER B — Prophase
RATIONALE During prophase, the diffuse chromatin fibers condense into discrete, visible
chromosomes — each consisting of two identical sister chromatids held together
at the centromere. This condensation makes chromosomes visible under the light
microscope for the first time in the cell cycle.
4. What is the function of a phosphatase?
A. A phosphatase adds phosphate groups to amino acid residues in a protein
B. A phosphatase removes the phosphate group from phosphorylated amino acid residues
in a protein
C. A phosphatase synthesizes ATP from ADP and inorganic phosphate
D. A phosphatase degrades proteins into their constituent amino acids
CORRECT ANSWER B — A phosphatase removes the phosphate group from phosphorylated
amino acid residues in a protein
RATIONALE Phosphatases catalyze the removal of phosphate groups (dephosphorylation)
from proteins, reversing the action of kinases. Together, kinases and
phosphatases form the core of intracellular signaling — phosphorylation activates
or deactivates proteins, and dephosphorylation resets them.
, 5. What two main products result from photosynthesis?
A. Carbon dioxide and water
B. Sugars/carbohydrates and oxygen
C. ATP and NADPH
D. Proteins and lipids
CORRECT ANSWER B — Sugars/carbohydrates and oxygen
RATIONALE Photosynthesis uses light energy, water, and carbon dioxide to produce
carbohydrates (sugars such as G3P) and oxygen. The overall equation is 6CO2 +
6H2O + light energy → C6H12O6 + 6O2. ATP and NADPH are intermediate energy
carriers, not net products.
6. At which stage of meiosis are sister chromatids separated from each other?
A. Anaphase I
B. Anaphase II
C. Metaphase I
D. Prophase I
CORRECT ANSWER B — Anaphase II
RATIONALE In meiosis, sister chromatids are separated during anaphase II. During anaphase I,
homologous chromosomes are separated. The sister chromatids remain attached
until anaphase II, when cohesin proteins are cleaved and chromatids finally
separate.
2 MAXE · 171 OIB
★ ★
M College of Literature, Science & the Arts — Department of Biology
EST. 1817
ARTES · SCIENTIA · VERITAS
Bio 171 Exam 2
C E L LU L A R R E S P I RAT I O N · P H OTO SY N T H E S I S · C E L L S I G N A L I N G · M I TO S I S · M E I O S I S
· G E N E T I CS
INSTITUTION University of Michigan PROGRAM Bachelor of Science — Biology
COURSE CODE BIO 171 COURSE TITLE Introduction to Molecular &
Cellular Biology
ACADEMIC YEAR EXAM TITLE Bio 171 Exam 2
TOTAL QUESTIONS 97 Questions FORMAT Multiple Choice — Select the
Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This examination covers cellular respiration, photosynthesis, cell signaling, mitosis, meiosis, genetics,
and bioenergetics.
▸ Questions address glycolysis, the citric acid cycle, oxidative phosphorylation, the Calvin cycle, receptor
signaling, the cell cycle, and Mendelian genetics.
▸ Correct answers and explanatory rationales appear below each question for review purposes.
▸ All content reflects standard introductory biology curriculum for BIO 171 at the University of Michigan.
, SECTION I — CELLULAR RESPIRATION, PHOTOSYNTHESIS
Questions 1 – 97
& GENETICS
1. Why are ion channels necessary to transport ions into or out of a cell?
A. Ions are too large to cross the membrane by any means
B. Ions are charged particles and cannot diffuse through the hydrophobic interior of the
membrane
C. Ions require active transport pumps exclusively for all movement
D. Ions are soluble only in the lipid bilayer without assistance
CORRECT ANSWER B — Ions are charged particles and cannot diffuse through the hydrophobic
interior of the membrane
RATIONALE The plasma membrane's interior is composed of hydrophobic fatty acid tails that
repel charged particles. Ions such as Na+, K+, Ca2+, and Cl- are charged and
therefore cannot pass through the nonpolar lipid bilayer by simple diffusion. Ion
channels provide hydrophilic pores that allow specific ions to cross the
membrane down their electrochemical gradients. This is a fundamental principle
of membrane transport.
2. What compound receives electrons from NADH in the electron transport chain?
A. Carbon dioxide
B. Oxygen
C. Glucose
D. ATP
CORRECT ANSWER B — Oxygen
RATIONALE Oxygen is the final electron acceptor in the electron transport chain. NADH
donates electrons to Complex I, and they flow through the chain of protein
complexes, ultimately being transferred to molecular oxygen (O2), which
combines with hydrogen ions to form water. This is why oxygen is essential for
aerobic respiration.
,3. At which stage of mitosis do the chromosomes become visible under a light microscope?
A. Interphase
B. Prophase
C. Metaphase
D. Anaphase
CORRECT ANSWER B — Prophase
RATIONALE During prophase, the diffuse chromatin fibers condense into discrete, visible
chromosomes — each consisting of two identical sister chromatids held together
at the centromere. This condensation makes chromosomes visible under the light
microscope for the first time in the cell cycle.
4. What is the function of a phosphatase?
A. A phosphatase adds phosphate groups to amino acid residues in a protein
B. A phosphatase removes the phosphate group from phosphorylated amino acid residues
in a protein
C. A phosphatase synthesizes ATP from ADP and inorganic phosphate
D. A phosphatase degrades proteins into their constituent amino acids
CORRECT ANSWER B — A phosphatase removes the phosphate group from phosphorylated
amino acid residues in a protein
RATIONALE Phosphatases catalyze the removal of phosphate groups (dephosphorylation)
from proteins, reversing the action of kinases. Together, kinases and
phosphatases form the core of intracellular signaling — phosphorylation activates
or deactivates proteins, and dephosphorylation resets them.
, 5. What two main products result from photosynthesis?
A. Carbon dioxide and water
B. Sugars/carbohydrates and oxygen
C. ATP and NADPH
D. Proteins and lipids
CORRECT ANSWER B — Sugars/carbohydrates and oxygen
RATIONALE Photosynthesis uses light energy, water, and carbon dioxide to produce
carbohydrates (sugars such as G3P) and oxygen. The overall equation is 6CO2 +
6H2O + light energy → C6H12O6 + 6O2. ATP and NADPH are intermediate energy
carriers, not net products.
6. At which stage of meiosis are sister chromatids separated from each other?
A. Anaphase I
B. Anaphase II
C. Metaphase I
D. Prophase I
CORRECT ANSWER B — Anaphase II
RATIONALE In meiosis, sister chromatids are separated during anaphase II. During anaphase I,
homologous chromosomes are separated. The sister chromatids remain attached
until anaphase II, when cohesin proteins are cleaved and chromatids finally
separate.
