Biology 212 Exam 1 Questions and
Answers
How does one determine the number of covalent bonds an element will likely form? - CORRECT
ANSWERS -The number of valence electrons
What properties make water an excellent solvent? - CORRECT ANSWERS -Polarity, molecular
shape, hydrogen bonding
An amphipathic molecule contains what? - CORRECT ANSWERS -Both hydrophilic and
hydrophobic zones
We find an unknown liquid that is non-polar. When it is placed in water, what can we expect to
happen? - CORRECT ANSWERS -The unknown liquid will not dissolve
A newly discovered organelle breaks apart a protein and puts it back together. Which processes
are used? - CORRECT ANSWERS -Hydrolysis and dehydration reactions
Pasteur used two types of flasks in his famous experiment: an open-top and a swan-necked
flask. What was the experimental variable? - CORRECT ANSWERS -Access to microbes in the air
What is responsible for lipid bilayer formation in water with phospholipids? - CORRECT
ANSWERS -Amphipathic properties of phospholipids
What type of transport mechanism could be used to move a molecule of glucose across a
membrane against a concentration gradient? - CORRECT ANSWERS -Active transport
As lipids become less saturated, we expect membrane permeability to - CORRECT ANSWERS -
Increase
Peripheral membrane proteins differ from transmembrane proteins in that they - CORRECT
ANSWERS -Do not cross the lipid bilayer
A toxin is known to disrupt actin filaments and microtubules. Which cell structure and function
are most affected? - CORRECT ANSWERS -Cytoskeleton - cell movements
Which of the following can be found in prokaryotic cells? - CORRECT ANSWERS -Ribosomes
A pure phospholipid membrane separates two chambers of water. Oxygen molecules and
potassium ions are added to the water in Chamber #1. You return to the chamber after a few
days and notice that everything that was added is now present in Chamber #2. What is the
relative permeability of these molecules across this lipid bilayer from most permeable to least
permeable? - CORRECT ANSWERS -Oxygen, water, potassium
, Chamber A is separated from Chamber B by a phospholipid membrane that contains only water
permeable channels. If Chamber A contains 0.4 M sodium in solution and chamber B contains
0.1 M sodium in solution, in which direction will the water flow and what would equilibrium
be? - CORRECT ANSWERS -Water will move from Chamber A to Chamber B, equilibrium would
be 0.25 M
A cell containing a phospholipid membrane that typically transports sodium using an ATP-
driven sodium pump is prevented from making additional ATP. Which of the following
statements is true regarding the cell? - CORRECT ANSWERS -The pump still stop pumping
sodium against the concentration gradient
Consider a lipid membrane consisting of fatty acids with two double bonds. What would you
expect of the resulting membrane? - CORRECT ANSWERS -The membrane has fluidity
A cell is moved from a warm incubator to a cold lab bench. Which of the following adjustments
could the cell make to keep membrane fluidity the same? - CORRECT ANSWERS -Increase
proportion of unsaturated hydrocarbon tails in the membrane phospholipids
While traveling the world, you have encountered a new insect that lives in the extreme heat of
the African desert. When you bring the insect back to Iowa it begins to die, likely because it is
unable to maintain membrane homeostasis. What would increase this insect's ability to cope
with this temperature change? - CORRECT ANSWERS -Increase the amount of unsaturated fatty
acids
A Pulse-Chase experiment using radioactive amino acids is completed to track the passage of
proteins in pancreatic cells, where we know proteins are commonly secreted from the cells.
However, after the experiment is concluded, no proteins are being secreted. However, protein
is being made in the cell. Which of the following organelles is not likely the source of
dysfunction in the cell? - CORRECT ANSWERS -Nucleus
A phospholipid membrane bilayer contains multiple integral membrane proteins, meaning that
the proteins span the length of the membrane. These proteins act as channels, allowing for the
passage of water. What is likely the distribution of the polar and non-polar amino acids that
make up these proteins? - CORRECT ANSWERS -There will be a higher concentration of polar
amino acids facing the inside of the channel and there will be a high concentration of non-polar
amino acids facing outward toward the membrane
You notice a material exiting a cell nucleus through a nuclear pore. This material is most likely -
CORRECT ANSWERS -RNA
You track a labeled protein and realize it is in a secretory vesicle. Based on what you know
about protein trafficking, the protein was in the __________ before and is heading toward the
__________. - CORRECT ANSWERS -Golgi apparatus; Plasma membrane
Answers
How does one determine the number of covalent bonds an element will likely form? - CORRECT
ANSWERS -The number of valence electrons
What properties make water an excellent solvent? - CORRECT ANSWERS -Polarity, molecular
shape, hydrogen bonding
An amphipathic molecule contains what? - CORRECT ANSWERS -Both hydrophilic and
hydrophobic zones
We find an unknown liquid that is non-polar. When it is placed in water, what can we expect to
happen? - CORRECT ANSWERS -The unknown liquid will not dissolve
A newly discovered organelle breaks apart a protein and puts it back together. Which processes
are used? - CORRECT ANSWERS -Hydrolysis and dehydration reactions
Pasteur used two types of flasks in his famous experiment: an open-top and a swan-necked
flask. What was the experimental variable? - CORRECT ANSWERS -Access to microbes in the air
What is responsible for lipid bilayer formation in water with phospholipids? - CORRECT
ANSWERS -Amphipathic properties of phospholipids
What type of transport mechanism could be used to move a molecule of glucose across a
membrane against a concentration gradient? - CORRECT ANSWERS -Active transport
As lipids become less saturated, we expect membrane permeability to - CORRECT ANSWERS -
Increase
Peripheral membrane proteins differ from transmembrane proteins in that they - CORRECT
ANSWERS -Do not cross the lipid bilayer
A toxin is known to disrupt actin filaments and microtubules. Which cell structure and function
are most affected? - CORRECT ANSWERS -Cytoskeleton - cell movements
Which of the following can be found in prokaryotic cells? - CORRECT ANSWERS -Ribosomes
A pure phospholipid membrane separates two chambers of water. Oxygen molecules and
potassium ions are added to the water in Chamber #1. You return to the chamber after a few
days and notice that everything that was added is now present in Chamber #2. What is the
relative permeability of these molecules across this lipid bilayer from most permeable to least
permeable? - CORRECT ANSWERS -Oxygen, water, potassium
, Chamber A is separated from Chamber B by a phospholipid membrane that contains only water
permeable channels. If Chamber A contains 0.4 M sodium in solution and chamber B contains
0.1 M sodium in solution, in which direction will the water flow and what would equilibrium
be? - CORRECT ANSWERS -Water will move from Chamber A to Chamber B, equilibrium would
be 0.25 M
A cell containing a phospholipid membrane that typically transports sodium using an ATP-
driven sodium pump is prevented from making additional ATP. Which of the following
statements is true regarding the cell? - CORRECT ANSWERS -The pump still stop pumping
sodium against the concentration gradient
Consider a lipid membrane consisting of fatty acids with two double bonds. What would you
expect of the resulting membrane? - CORRECT ANSWERS -The membrane has fluidity
A cell is moved from a warm incubator to a cold lab bench. Which of the following adjustments
could the cell make to keep membrane fluidity the same? - CORRECT ANSWERS -Increase
proportion of unsaturated hydrocarbon tails in the membrane phospholipids
While traveling the world, you have encountered a new insect that lives in the extreme heat of
the African desert. When you bring the insect back to Iowa it begins to die, likely because it is
unable to maintain membrane homeostasis. What would increase this insect's ability to cope
with this temperature change? - CORRECT ANSWERS -Increase the amount of unsaturated fatty
acids
A Pulse-Chase experiment using radioactive amino acids is completed to track the passage of
proteins in pancreatic cells, where we know proteins are commonly secreted from the cells.
However, after the experiment is concluded, no proteins are being secreted. However, protein
is being made in the cell. Which of the following organelles is not likely the source of
dysfunction in the cell? - CORRECT ANSWERS -Nucleus
A phospholipid membrane bilayer contains multiple integral membrane proteins, meaning that
the proteins span the length of the membrane. These proteins act as channels, allowing for the
passage of water. What is likely the distribution of the polar and non-polar amino acids that
make up these proteins? - CORRECT ANSWERS -There will be a higher concentration of polar
amino acids facing the inside of the channel and there will be a high concentration of non-polar
amino acids facing outward toward the membrane
You notice a material exiting a cell nucleus through a nuclear pore. This material is most likely -
CORRECT ANSWERS -RNA
You track a labeled protein and realize it is in a secretory vesicle. Based on what you know
about protein trafficking, the protein was in the __________ before and is heading toward the
__________. - CORRECT ANSWERS -Golgi apparatus; Plasma membrane
