BS 161 EXAM 2 COMPLETE PRACTICE EXAM
QUESTIONS AND CORRECT DETAILED
ANSWERS LATEST UPDATE GRADED A+
The lipid components of cellular membranes often include:
fatty acids and cholesterol.
phospholipids and fatty acids.
phospholipids and cholesterol.
phospholipids --CORRECT ANSWER--phospholipids and cholesterol.
In response to seasonal changes in temperature, many organisms must alter the
composition of their plasma membranes to maintain the proper degree of
fluidity. As summer turns to fall and eventually into winter, which of the
following would you predict you would observe in the plasma membranes of
organisms that are unable to regulate their body temperature?
a decrease in phospholipid fatty acid side chain length and an increase in side
chain saturation
an increase in phospholipid fatty acid side chain length and an increase in side
chain saturation
a decrease in phospholipid fatty acid side chain length and a decrease in side
chain saturation
an increase in phospholipid fatty acid side chain length and a decrease in side
chain saturation --CORRECT ANSWER--a decrease in phospholipid fatty acid
side chain length and a decrease in side chain saturation
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,Which of the following is least likely to cross a lipid bilayer with no proteins?
a steroid hormone such as testosterone
CO2
H2O
ATP
O2 --CORRECT ANSWER--ATP
Which one of the following describes the hydrophilic component of cholesterol?
a phosphate group only
a hydroxyl group only
a single hydrocarbon tail
a phosphate group and a chemical group called choline
a group of four planar rings and a hydroxyl group --CORRECT ANSWER--a
hydroxyl group only
In intestinal epithelial cells, a transport protein moves glucose into the
cytoplasm against its concentration gradient at the same time that it transports
Na+ into the cell down its electrochemical gradient. Which of the following
CORRECTLY describes this cotransport of glucose and sodium?
Energy from ATP directly drives the movement of glucose
Page | 2
,No energy source is required for glucose to move against its concentration
gradient
Na+ can move by simple diffusion, but glucose transport requires a carrier
protein
The Na+ concentration gradient provides the energy for glucose transport --
CORRECT ANSWER--The Na+ concentration gradient provides the energy for
glucose transport
Which component of a phospholipid is found in the interior of a lipid bilayer?
fatty acids
glycerol
phosphate group --CORRECT ANSWER--fatty acids
Suppose you are studying the transport of a certain polar molecule across the
plasma membrane of cells in culture. Over a period of time, you measure the
concentration of a polar molecule inside and outside of the cells. You find that
the concentration of the molecule is lower in the cell but is gradually increasing.
You also measure the ATP concentration inside the cell and find that it is not
changing. Which of the following is probably responsible for the transport of
this polar substance into the cell?
endocytosis
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, simple diffusion
active transport
secondary active transport
facilitated diffusion --CORRECT ANSWER--Facilitated diffusion
Which of the following represents the order that molecules cross a synthetic
membrane composed of phospholipids but not proteins, from most easily (freely
permeable) to least easily (not permeable)?
O2, sodium ions (Na+), water (H2O), glucose
O2, water (H2O), glucose, sodium ions (Na+)
water (H2O), glucose, sodium ions (Na+), O2
sodium ions (Na+), glucose, water (H2O), O2
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QUESTIONS AND CORRECT DETAILED
ANSWERS LATEST UPDATE GRADED A+
The lipid components of cellular membranes often include:
fatty acids and cholesterol.
phospholipids and fatty acids.
phospholipids and cholesterol.
phospholipids --CORRECT ANSWER--phospholipids and cholesterol.
In response to seasonal changes in temperature, many organisms must alter the
composition of their plasma membranes to maintain the proper degree of
fluidity. As summer turns to fall and eventually into winter, which of the
following would you predict you would observe in the plasma membranes of
organisms that are unable to regulate their body temperature?
a decrease in phospholipid fatty acid side chain length and an increase in side
chain saturation
an increase in phospholipid fatty acid side chain length and an increase in side
chain saturation
a decrease in phospholipid fatty acid side chain length and a decrease in side
chain saturation
an increase in phospholipid fatty acid side chain length and a decrease in side
chain saturation --CORRECT ANSWER--a decrease in phospholipid fatty acid
side chain length and a decrease in side chain saturation
Page | 1
,Which of the following is least likely to cross a lipid bilayer with no proteins?
a steroid hormone such as testosterone
CO2
H2O
ATP
O2 --CORRECT ANSWER--ATP
Which one of the following describes the hydrophilic component of cholesterol?
a phosphate group only
a hydroxyl group only
a single hydrocarbon tail
a phosphate group and a chemical group called choline
a group of four planar rings and a hydroxyl group --CORRECT ANSWER--a
hydroxyl group only
In intestinal epithelial cells, a transport protein moves glucose into the
cytoplasm against its concentration gradient at the same time that it transports
Na+ into the cell down its electrochemical gradient. Which of the following
CORRECTLY describes this cotransport of glucose and sodium?
Energy from ATP directly drives the movement of glucose
Page | 2
,No energy source is required for glucose to move against its concentration
gradient
Na+ can move by simple diffusion, but glucose transport requires a carrier
protein
The Na+ concentration gradient provides the energy for glucose transport --
CORRECT ANSWER--The Na+ concentration gradient provides the energy for
glucose transport
Which component of a phospholipid is found in the interior of a lipid bilayer?
fatty acids
glycerol
phosphate group --CORRECT ANSWER--fatty acids
Suppose you are studying the transport of a certain polar molecule across the
plasma membrane of cells in culture. Over a period of time, you measure the
concentration of a polar molecule inside and outside of the cells. You find that
the concentration of the molecule is lower in the cell but is gradually increasing.
You also measure the ATP concentration inside the cell and find that it is not
changing. Which of the following is probably responsible for the transport of
this polar substance into the cell?
endocytosis
Page | 3
, simple diffusion
active transport
secondary active transport
facilitated diffusion --CORRECT ANSWER--Facilitated diffusion
Which of the following represents the order that molecules cross a synthetic
membrane composed of phospholipids but not proteins, from most easily (freely
permeable) to least easily (not permeable)?
O2, sodium ions (Na+), water (H2O), glucose
O2, water (H2O), glucose, sodium ions (Na+)
water (H2O), glucose, sodium ions (Na+), O2
sodium ions (Na+), glucose, water (H2O), O2
Page | 4
