BIOLOGY 181 CORE EXAM MANUAL 2025/2026 QUESTIONS
AND ANSWERS GRADED A+
✔✔Which of the following statements regarding the amino acid glycine is false?
A) Only the L isoform of glycine is found in proteins
B) Glycine has the a hydrogen atom for a side chain
C) Its side chain is small enough to allow glycine to fit into tight corners of protein
molecules
D) The side chain of glycine is uncharged throughout the pH scale - ✔✔A
✔✔What is the theoretical number of different proteins that you could make from 10
amino acids?
A) 10^20
B) 20^10
C) 20 × 10
D) 20!/(20-10)! - ✔✔B
✔✔The difference between α- and β-glucose is _______.
A) based on whether the side chain is attached to the alpha- or beta-carbon
B) in the configuration of OH and H groups around carbon 1 in the ring form of the sugar
C) in that α-glucose is linear, whereas β-glucose has a ring structure
D) that α-glucose is polar, whereas β-glucose is nonpolar.
E) that α-glucose is a pentose, whereas β-glucose is a hexose - ✔✔B
✔✔The backbones of DNA and RNA consist of:
A) amyloses
B) fructoses
C) hexoses
D) maltoses
E) pentoses - ✔✔E
✔✔Amylopectin and glycogen, which are both polysaccharides, differ structurally in that
glycogen _______, whereas starch _______.
A) is highly branched; consists of parallel strands
B) consists of a combination of branching and parallel strands; is moderately branched
C) is moderately branched; consists of parallel strands
D) is highly branched; is moderately branched
E) consists of parallel strands; is highly branched - ✔✔E
✔✔The most common secondary structure found in membrane-spanning proteins is:
A) An alpha helix of charged amino acids that passes through the membrane.
B) none of these
C) an alpha helix of nonpolar amino acids that passes through the membrane
D) a helix-turn-helix arrangement of the peptide strands.
,E) triple helix of alpha helices - ✔✔C
✔✔Which of the following amino acids have very similar side chains with extremely
similar chemical properties? (mark as many as applicable)
A) serine
B) threonine
C) aspartate
D) glycine - ✔✔A B
✔✔Identify the hydrophobic amino acids from the list below (more than one correct
answer possible):
A) tryptophan
B) isoleucine
C) lysine
D) aspartate
E) serine - ✔✔A B
✔✔The loss of flagellin in Pseudomonas aeruginosa exosed to CF patients' mucus may
have an adventage as described in the previous question, however this is certainly a
case of fitness tradeoff. What do the bacteria give up when they stop producing
flagellin?
A) P. aeruginosa cells that repress their flagellin production lose their ability to
exchange DNA fragments.
B) P. aeruginosa cells that repress their flagellin production cannot swim.
C) P. aeruginosa that repress their flagellin production are greatly impaired in their
ability to translate other protiens.
D) P. aeruginosa cells that repress their flagellin production can no longer regulate the
movement of molecules into and out of the cell.
E) P. aeruginosa cells that repress their flagellin production have a higher tendency to
get dehydrated. - ✔✔B
✔✔As mentioned above, the loss of flagellin expression "allows P. aeruginosa to avoid
[...] phagocytosis". What does "phagocytosis" likely mean in this context?
A) Phagocytosis is the process by which cells can regulate the movement of molecules
into and out of the cell. The loss of flagellin leads to the loss of such control and thus
helps P. aeruginosa avoid phagocytosis.
B) Phagocytosis is the process by which cells can engulf large particles or even entire
cells. For example, types of white blood cells which constitute part of our immune
system, can "gobble" up foreign substances like invading bacteria.
C) Phagocytosis is the process by which cells can engulf large particles or even entire
cells. For example some unicellular eukaryotic organisms (protists) feed this way, which
explains how P. aeruginosa can feed on mucus
D) Phagocytosis, a word derived from the same root-word that gave us "spigot", is the
way that - ✔✔B
, ✔✔Which of the following organelles are surrounded by a double-membrane envelope?
A) a nucleolus
B) a lysosome
C) a Golgi apparatus
D) a nucleus
E) a ribosome
F) a mitochondrion
G) a chloroplast - ✔✔D F G
✔✔The rough ER is the portion of the ER that ______.
A) is the site of steroid synthesis
B) has ribosomes attached to it.
C) lacks ribosomes
D) is the oldest and was once the smooth ER.
E) is the oldest and was once the smooth ER. - ✔✔B
✔✔What do ribosomes and spliceosomes have in common beyond the fact that they
are both essential for gene expression? - ✔✔Besides gene expression, ribosomes and
spliceosomes are both comprised of RNA and proteins. Both are responsible for
carrying mRNA
✔✔What can you infer about a high molecular weight protein that cannot be transported
into the nucleus?
A) It doesn't bind to RNA
B) It is too large
C) It lacks a nuclear localization signal (NLS)
D) It contains errors in its amino acid sequence - ✔✔C
✔✔Which of the following is a mischaracterization of mitochondrial DNA?
A) Mitochondrial DNA is similar in organization, but not in complexity, to that of the
bacterial DNA
B) Mitochondrial DNA is organized into multiple linear chromosomes
C) Mitochondrial DNA is an evolutionary relic
D) Mitochondrial DNA carry very few genes that are, nonetheless, absolutely essential
for cellular respiration
E) Mitochondrial DNA is transcribed by a mitochondrial RNA polymerases and the
mRNA is translated by ribosomes which are smaller than the cytoplasmic ribosomes -
✔✔B
✔✔Which of the following regarding the cell in the previous question is true?
A) The cell is probably motile (can swim).
B) The cell is prokaryotic
C) The cell is likely to be colorless
D) The cell is most likely to be heterotrophic
AND ANSWERS GRADED A+
✔✔Which of the following statements regarding the amino acid glycine is false?
A) Only the L isoform of glycine is found in proteins
B) Glycine has the a hydrogen atom for a side chain
C) Its side chain is small enough to allow glycine to fit into tight corners of protein
molecules
D) The side chain of glycine is uncharged throughout the pH scale - ✔✔A
✔✔What is the theoretical number of different proteins that you could make from 10
amino acids?
A) 10^20
B) 20^10
C) 20 × 10
D) 20!/(20-10)! - ✔✔B
✔✔The difference between α- and β-glucose is _______.
A) based on whether the side chain is attached to the alpha- or beta-carbon
B) in the configuration of OH and H groups around carbon 1 in the ring form of the sugar
C) in that α-glucose is linear, whereas β-glucose has a ring structure
D) that α-glucose is polar, whereas β-glucose is nonpolar.
E) that α-glucose is a pentose, whereas β-glucose is a hexose - ✔✔B
✔✔The backbones of DNA and RNA consist of:
A) amyloses
B) fructoses
C) hexoses
D) maltoses
E) pentoses - ✔✔E
✔✔Amylopectin and glycogen, which are both polysaccharides, differ structurally in that
glycogen _______, whereas starch _______.
A) is highly branched; consists of parallel strands
B) consists of a combination of branching and parallel strands; is moderately branched
C) is moderately branched; consists of parallel strands
D) is highly branched; is moderately branched
E) consists of parallel strands; is highly branched - ✔✔E
✔✔The most common secondary structure found in membrane-spanning proteins is:
A) An alpha helix of charged amino acids that passes through the membrane.
B) none of these
C) an alpha helix of nonpolar amino acids that passes through the membrane
D) a helix-turn-helix arrangement of the peptide strands.
,E) triple helix of alpha helices - ✔✔C
✔✔Which of the following amino acids have very similar side chains with extremely
similar chemical properties? (mark as many as applicable)
A) serine
B) threonine
C) aspartate
D) glycine - ✔✔A B
✔✔Identify the hydrophobic amino acids from the list below (more than one correct
answer possible):
A) tryptophan
B) isoleucine
C) lysine
D) aspartate
E) serine - ✔✔A B
✔✔The loss of flagellin in Pseudomonas aeruginosa exosed to CF patients' mucus may
have an adventage as described in the previous question, however this is certainly a
case of fitness tradeoff. What do the bacteria give up when they stop producing
flagellin?
A) P. aeruginosa cells that repress their flagellin production lose their ability to
exchange DNA fragments.
B) P. aeruginosa cells that repress their flagellin production cannot swim.
C) P. aeruginosa that repress their flagellin production are greatly impaired in their
ability to translate other protiens.
D) P. aeruginosa cells that repress their flagellin production can no longer regulate the
movement of molecules into and out of the cell.
E) P. aeruginosa cells that repress their flagellin production have a higher tendency to
get dehydrated. - ✔✔B
✔✔As mentioned above, the loss of flagellin expression "allows P. aeruginosa to avoid
[...] phagocytosis". What does "phagocytosis" likely mean in this context?
A) Phagocytosis is the process by which cells can regulate the movement of molecules
into and out of the cell. The loss of flagellin leads to the loss of such control and thus
helps P. aeruginosa avoid phagocytosis.
B) Phagocytosis is the process by which cells can engulf large particles or even entire
cells. For example, types of white blood cells which constitute part of our immune
system, can "gobble" up foreign substances like invading bacteria.
C) Phagocytosis is the process by which cells can engulf large particles or even entire
cells. For example some unicellular eukaryotic organisms (protists) feed this way, which
explains how P. aeruginosa can feed on mucus
D) Phagocytosis, a word derived from the same root-word that gave us "spigot", is the
way that - ✔✔B
, ✔✔Which of the following organelles are surrounded by a double-membrane envelope?
A) a nucleolus
B) a lysosome
C) a Golgi apparatus
D) a nucleus
E) a ribosome
F) a mitochondrion
G) a chloroplast - ✔✔D F G
✔✔The rough ER is the portion of the ER that ______.
A) is the site of steroid synthesis
B) has ribosomes attached to it.
C) lacks ribosomes
D) is the oldest and was once the smooth ER.
E) is the oldest and was once the smooth ER. - ✔✔B
✔✔What do ribosomes and spliceosomes have in common beyond the fact that they
are both essential for gene expression? - ✔✔Besides gene expression, ribosomes and
spliceosomes are both comprised of RNA and proteins. Both are responsible for
carrying mRNA
✔✔What can you infer about a high molecular weight protein that cannot be transported
into the nucleus?
A) It doesn't bind to RNA
B) It is too large
C) It lacks a nuclear localization signal (NLS)
D) It contains errors in its amino acid sequence - ✔✔C
✔✔Which of the following is a mischaracterization of mitochondrial DNA?
A) Mitochondrial DNA is similar in organization, but not in complexity, to that of the
bacterial DNA
B) Mitochondrial DNA is organized into multiple linear chromosomes
C) Mitochondrial DNA is an evolutionary relic
D) Mitochondrial DNA carry very few genes that are, nonetheless, absolutely essential
for cellular respiration
E) Mitochondrial DNA is transcribed by a mitochondrial RNA polymerases and the
mRNA is translated by ribosomes which are smaller than the cytoplasmic ribosomes -
✔✔B
✔✔Which of the following regarding the cell in the previous question is true?
A) The cell is probably motile (can swim).
B) The cell is prokaryotic
C) The cell is likely to be colorless
D) The cell is most likely to be heterotrophic
