Biol 1001 Midterm 2 Exam Questions
with Correct Answers
Because the CH bonds in the fatty acid tails are relatively no-par, the phospholipids
ails are ________ - ANSWER-Hydrophobic
Order of molecules from most permeable and least permeable to phospholipid
bilayer - ANSWER-1. Nonpolar molecules
2. Polar molecules
3. Ions
Function of cholesterol - ANSWER--Stabilization of phospholipids
-Enables to membrane to stay fluid more easily when cell temperature drops
Diffusion - ANSWER-Movement of particles down their concentration gradient
Difference between lipids and sugars? - ANSWER-Most notably would be that a
lipids is non polar while sugars are polar
Which of the following does NOT affect membrane permeability?
A The saturation of hydrocarbon tails in membrane phospholipids
B Temperature
C The polarity of membrane phospholipids
D The amount of cholesterol in the membrane - ANSWER-A, D
Which of these are attached to the ECM?
A Transmembrane Proteins
B Integral Proteins
C Glycoproteins
D Integrins
E Peripheral Proteins - ANSWER-D
Exocytosis - ANSWER--increases the SA of the plasma membrane
-secretes large molecules out of the cell
-requires fusion of vesicles with the plasma membrane
Endocytosis - ANSWER--decreases SA of plasma membrane
-forms vesicles from inward folding of the plasma membrane
Both endocytosis and exocytosis... - ANSWER--require cellular energy
-transported substances never physically cross the plasma membrane
According to the fluid mosaic model of membrane structure, proteins of the
membrane are mostly - ANSWER-Embedded in the lipid bilayer
Which of the following factors would tend to increase membrane fluidity?
,A a lower temperature
B a greater proportion of unsaturated phospholipids
C a greater proportion of saturated phospholipids
D a relatively high protein content in the membrane
E a greater proportion of relatively large glycolipids compared with lipids having
smaller molecular masses - ANSWER-B
Fimbriae - ANSWER-Surface appendages that allows bacterium to stick to a surface
Bacterial Capsule Function - ANSWER-Protection
Where is a bacterial cell's DNA found? - ANSWER-Nucleoid region
In a bacterium, where are proteins synthesized - ANSWER-Ribosomes
What is the name given to the rigid structure, found outside the plasma membrane,
that surrounds and supports the bacterial cell? - ANSWER-Cell Wall
What path does a protein in the secretory pathway take, starting from its site of
synthesis? - ANSWER-Rough ER, secretory vesicles, Golgi apparatus, plasma
membrane
Lysosome - ANSWER-Intracellular digestion
The volume enclosed by the plasma membrane of plant cells is often much larger
than the corresponding volume in animal cells. The most reasonable explanation for
this observation is that.... - ANSWER-Plant cells contain a large vacuole that reduces
the volume of the cytoplasm
Which of the following statements about a typical plasma membrane is correct?
A The two sides of the plasma membrane have different lipid and protein
composition.
B The plasma membrane is a covalently linked network of phospholipids and
proteins that controls the movement of solutes into and out of a cell.
C Carbohydrates on the membrane surface are important in determining the overall
bilayer structure.
D The hydrophilic interior of the membrane is composed primarily of the fatty acid
tails of the phospholipids.
E Phospholipids are the primary component that determines which solutes can cross
the plasma membrane. - ANSWER-A
Which of the following best describes the structure of a biological membrane?
A two layers of phospholipids (with opposite orientations of the phospholipids in each
layer) with each layer covered on the outside with proteins
B two layers of phospholipids with proteins either crossing the layers or on the
surface of the layers
C a mixture of covalently linked phospholipids and proteins that determines which
solutes can cross the membrane and which cannot
D two layers of phospholipids with proteins embedded between the two layers
,E a fluid structure in which phospholipids and proteins move freely between sides of
the membrane - ANSWER-B
The permeability of a biological membrane to a specific polar solute may depend on
which of the following? - ANSWER-The types of transport proteins in the membrane
Which of the following is LEAST likely to be important in holding the components of a
biological membrane together?
A hydrophobic interactions among the fatty acid tails of phospholipids on opposite
sides of the membrane
B covalent interactions between the phospholipid and protein components of the
membrane
C polar interactions among the phospholipid head groups on the same surface of the
membrane
D hydrophobic interactions among the fatty acid tails of phospholipids on the same
side of the membrane
E hydrophobic interactions between the phospholipid tails and the surface of integral
membrane proteins buried in the membrane - ANSWER-B
Smooth ER Function - ANSWER--lipid synthesis
-calcium ion storage
-poison detoxification
Rough ER Function - ANSWER-protein synthesis
Golgi Apparatus Function - ANSWER--protein modification and storage
-cisternal maturation
Lysosomes Function - ANSWER--macromolecule digestion
-autophagy
Where do proteins made from free ribosomes go? - ANSWER-functions in the
cytosol
Where do proteins made from bound ribosomes go? - ANSWER-functions outside of
cell/of membrane
What compose the cilia and flagella? What do they look like? - ANSWER--
Microtubules
-Centrioles
What does an animal cell have that a plant cell does not have? - ANSWER-
Centrioles, lysosomes, ECM, Gap tight and desmosomes
What does a plant cell have that an animal cell does not have - ANSWER--
Plasmodesmata
-Central Vacuole
-Cell Wall
-Chloroplasts
, What is true for chloroplasts?
1 They are the sites of reactions that convert solar energy into chemical energy.
2 Their matrix contains enzymes that function in cellular respiration.
3 Their inner membrane has infoldings called cristae.
4 They contain the green pigment chlorophyll.
5 They have membranous sacs called thylakoids that are surrounded by a fluid
called stroma.
6 They are the sites of reactions that convert chemical energy to ATP. - ANSWER-1,
4, 5
In eukaryotic flagella, the fibers that slide past one another due to the activity of dyne
proteins are... - ANSWER-microtubules
many cell organelles, most notably the nucleus, are anchored by_________, which
re assembled from a diverse class of proteins - ANSWER-intermediate filaments
centrosomes are sites where protein dimers assemble into ______ - ANSWER-
microtubules
the only cytoskeletal fibers not associated with intracellular movement or whole cell
locomotion are ____ - ANSWER-intermediate filaments
during muscle contractions, myosin motor proteins move across tracks of ______ -
ANSWER-microfilaments
Desmosomes - ANSWER-Membrane protein complexes that strengthen the
adhesion between adjacent cells, like rivets to protect against pulling forces
Gap Junctions - ANSWER-small channels that form across the plasma membranes
of the adjacent cells; especially important in intercellular communication
Tight Junctions - ANSWER-membrane proteins that create a watertight seal between
cells
Plasmodesmata - ANSWER-Small channels between cells that are otherwise
surrounded by walls; enables movement of water and solutes between cells
Cellulose - ANSWER-polysaccaride used to synthesize cell walls, which protect cells
and help maintain their shape
collagen - ANSWER-long fibers of protein found in the extracellular matrix that
provide structural support for cells
Which of these manufactures cellular membranes by adding membrane proteins and
phospholipids to its own membrane?
A nucleolus
B ribosomes
C rough endoplasmic reticulum
D Golgi apparatus
E lysosomes - ANSWER-C
with Correct Answers
Because the CH bonds in the fatty acid tails are relatively no-par, the phospholipids
ails are ________ - ANSWER-Hydrophobic
Order of molecules from most permeable and least permeable to phospholipid
bilayer - ANSWER-1. Nonpolar molecules
2. Polar molecules
3. Ions
Function of cholesterol - ANSWER--Stabilization of phospholipids
-Enables to membrane to stay fluid more easily when cell temperature drops
Diffusion - ANSWER-Movement of particles down their concentration gradient
Difference between lipids and sugars? - ANSWER-Most notably would be that a
lipids is non polar while sugars are polar
Which of the following does NOT affect membrane permeability?
A The saturation of hydrocarbon tails in membrane phospholipids
B Temperature
C The polarity of membrane phospholipids
D The amount of cholesterol in the membrane - ANSWER-A, D
Which of these are attached to the ECM?
A Transmembrane Proteins
B Integral Proteins
C Glycoproteins
D Integrins
E Peripheral Proteins - ANSWER-D
Exocytosis - ANSWER--increases the SA of the plasma membrane
-secretes large molecules out of the cell
-requires fusion of vesicles with the plasma membrane
Endocytosis - ANSWER--decreases SA of plasma membrane
-forms vesicles from inward folding of the plasma membrane
Both endocytosis and exocytosis... - ANSWER--require cellular energy
-transported substances never physically cross the plasma membrane
According to the fluid mosaic model of membrane structure, proteins of the
membrane are mostly - ANSWER-Embedded in the lipid bilayer
Which of the following factors would tend to increase membrane fluidity?
,A a lower temperature
B a greater proportion of unsaturated phospholipids
C a greater proportion of saturated phospholipids
D a relatively high protein content in the membrane
E a greater proportion of relatively large glycolipids compared with lipids having
smaller molecular masses - ANSWER-B
Fimbriae - ANSWER-Surface appendages that allows bacterium to stick to a surface
Bacterial Capsule Function - ANSWER-Protection
Where is a bacterial cell's DNA found? - ANSWER-Nucleoid region
In a bacterium, where are proteins synthesized - ANSWER-Ribosomes
What is the name given to the rigid structure, found outside the plasma membrane,
that surrounds and supports the bacterial cell? - ANSWER-Cell Wall
What path does a protein in the secretory pathway take, starting from its site of
synthesis? - ANSWER-Rough ER, secretory vesicles, Golgi apparatus, plasma
membrane
Lysosome - ANSWER-Intracellular digestion
The volume enclosed by the plasma membrane of plant cells is often much larger
than the corresponding volume in animal cells. The most reasonable explanation for
this observation is that.... - ANSWER-Plant cells contain a large vacuole that reduces
the volume of the cytoplasm
Which of the following statements about a typical plasma membrane is correct?
A The two sides of the plasma membrane have different lipid and protein
composition.
B The plasma membrane is a covalently linked network of phospholipids and
proteins that controls the movement of solutes into and out of a cell.
C Carbohydrates on the membrane surface are important in determining the overall
bilayer structure.
D The hydrophilic interior of the membrane is composed primarily of the fatty acid
tails of the phospholipids.
E Phospholipids are the primary component that determines which solutes can cross
the plasma membrane. - ANSWER-A
Which of the following best describes the structure of a biological membrane?
A two layers of phospholipids (with opposite orientations of the phospholipids in each
layer) with each layer covered on the outside with proteins
B two layers of phospholipids with proteins either crossing the layers or on the
surface of the layers
C a mixture of covalently linked phospholipids and proteins that determines which
solutes can cross the membrane and which cannot
D two layers of phospholipids with proteins embedded between the two layers
,E a fluid structure in which phospholipids and proteins move freely between sides of
the membrane - ANSWER-B
The permeability of a biological membrane to a specific polar solute may depend on
which of the following? - ANSWER-The types of transport proteins in the membrane
Which of the following is LEAST likely to be important in holding the components of a
biological membrane together?
A hydrophobic interactions among the fatty acid tails of phospholipids on opposite
sides of the membrane
B covalent interactions between the phospholipid and protein components of the
membrane
C polar interactions among the phospholipid head groups on the same surface of the
membrane
D hydrophobic interactions among the fatty acid tails of phospholipids on the same
side of the membrane
E hydrophobic interactions between the phospholipid tails and the surface of integral
membrane proteins buried in the membrane - ANSWER-B
Smooth ER Function - ANSWER--lipid synthesis
-calcium ion storage
-poison detoxification
Rough ER Function - ANSWER-protein synthesis
Golgi Apparatus Function - ANSWER--protein modification and storage
-cisternal maturation
Lysosomes Function - ANSWER--macromolecule digestion
-autophagy
Where do proteins made from free ribosomes go? - ANSWER-functions in the
cytosol
Where do proteins made from bound ribosomes go? - ANSWER-functions outside of
cell/of membrane
What compose the cilia and flagella? What do they look like? - ANSWER--
Microtubules
-Centrioles
What does an animal cell have that a plant cell does not have? - ANSWER-
Centrioles, lysosomes, ECM, Gap tight and desmosomes
What does a plant cell have that an animal cell does not have - ANSWER--
Plasmodesmata
-Central Vacuole
-Cell Wall
-Chloroplasts
, What is true for chloroplasts?
1 They are the sites of reactions that convert solar energy into chemical energy.
2 Their matrix contains enzymes that function in cellular respiration.
3 Their inner membrane has infoldings called cristae.
4 They contain the green pigment chlorophyll.
5 They have membranous sacs called thylakoids that are surrounded by a fluid
called stroma.
6 They are the sites of reactions that convert chemical energy to ATP. - ANSWER-1,
4, 5
In eukaryotic flagella, the fibers that slide past one another due to the activity of dyne
proteins are... - ANSWER-microtubules
many cell organelles, most notably the nucleus, are anchored by_________, which
re assembled from a diverse class of proteins - ANSWER-intermediate filaments
centrosomes are sites where protein dimers assemble into ______ - ANSWER-
microtubules
the only cytoskeletal fibers not associated with intracellular movement or whole cell
locomotion are ____ - ANSWER-intermediate filaments
during muscle contractions, myosin motor proteins move across tracks of ______ -
ANSWER-microfilaments
Desmosomes - ANSWER-Membrane protein complexes that strengthen the
adhesion between adjacent cells, like rivets to protect against pulling forces
Gap Junctions - ANSWER-small channels that form across the plasma membranes
of the adjacent cells; especially important in intercellular communication
Tight Junctions - ANSWER-membrane proteins that create a watertight seal between
cells
Plasmodesmata - ANSWER-Small channels between cells that are otherwise
surrounded by walls; enables movement of water and solutes between cells
Cellulose - ANSWER-polysaccaride used to synthesize cell walls, which protect cells
and help maintain their shape
collagen - ANSWER-long fibers of protein found in the extracellular matrix that
provide structural support for cells
Which of these manufactures cellular membranes by adding membrane proteins and
phospholipids to its own membrane?
A nucleolus
B ribosomes
C rough endoplasmic reticulum
D Golgi apparatus
E lysosomes - ANSWER-C
