unit 3 test Flashcards
Which of the following molecules cannot diffuse across the plasma membrane?
calcium
water
oxygen
nitrogen
calcium
The cells walls of bacteria are composed of:
phospholipids.
peptidoglycan.
cellulose.
lipopolysaccharides.
peptidoglycan.
Which of the following molecules do you think would diffuse across a phospholipid bilayer fastest? Assume that there are no proteins associated with the bilayer.
Na+
Water
NH4+
O2
O2
You are studying an integral transmembrane protein and you notice that is has a region enriched with leucine, alanine, and tryptophan amino acids. Which of the following would be the better hypothesis?
This region is likely on the interior of the cell, exposed to the aqueous cytosol.
This region is likely part of the proteins that passes through the membrane.
This region is likely on the exterior of the cell, exposed to the aqueous environment.
This region really could be anywhere in the protein; the chemistry of these amino acids isn’t important.
This region is likely part of the proteins that passes through the membrane.
When the concentration of water inside a cell is higher then the concentration of water outside a cell, the inside solution is said to be ___________ to the outside solution.
hypotonic
Which of the following statements about membrane proteins is FALSE?
Some serve as channels for ions to cross the membrane.
Some of the membrane proteins are enzymes.
They all extend from one side of the membrane to the other.
Many move about freely in the membrane.
They all extend from one side of the membrane to the other.
Receptor-mediated endocytosis differs from phagocytosis in that:
fusion of vesicles with lysosomes takes place only in receptor-mediated endocytosis.
receptor-mediated endocytosis is very specific for what is taken into the cell.
fusion of vesicles with lysosomes takes place only in phagocytosis.
coated vesicles are formed in phagocytosis.
phagocytosis is very specific for what is taken into the cell.
receptor-mediated endocytosis is very specific for what is taken into the cell.
True or false: All symport carrier use passive transport.
False
Which of the following statements about the plasma membrane is FALSE?
It is made of lipids.
It is a flexible, fluid-like structure.
It separates the cytoplasm from the external environment.
It is a feature of eukaryotes, but not prokaryotes.
It is a feature of eukaryotes, but not prokaryotes.
To enter or leave any cell, substance must pass through ______.
the Golgi apparatus
a ribosome
a cell wall
the plasma membrane
a nucleus
the plasma membrane
G-protein coupled receptors are also called _______ receptors.
serpensortia
serpentine
slytherin
severus
serpentine
The interior space of the mitochondrion is called the:
granum
matrix
cristae
lumen
stroma
matrix
Proteins destined to be delivered to the exterior of cells are made in the rough ER and are:
packaged into vesicles that fuse with the Golgi apparatus.
Which of the following is a motor protein?
actin
kinesin
tubulin
keratin
kinesin
Where can Collagen be found
in the extracellular matrix.
If I used a pair of incredibly tiny forceps to pull the DNA directly from a cell’s nucleus, what macromolecules would I find?
nucleic acids and lipids
proteins and lipids
nucleic acids and carbohydrates
nucleic acids and proteins
proteins and carbohydrates
nucleic acids and proteins
When GTP is bound to G-protiens, the G-protein is:
inactive
active
phosphorylated
released from the membrane
active
G-proteins are inactivated when:
they bind cAMP.
they are phosphorylated.
GTP is hydrolyzed to GDP.
GDP combines with a free phosphate to make GTP.
GTP is hydrolyzed to GDP.
Which of the following proteins has no catalytic activity?
Phospholipase
G-protein
Adenylyl cyclase
G-protein coupled receptor
G-protein coupled receptor
Which organelles were probably once independent prokaryote organisms?
Mitochondria and chloroplasts
The mitochondrial electron transport chain, ___ the _____ electron carriers, __ and __.
oxidizes
intermediate
NADH and FADH2
Acetyl-coA is a ________-carbon molecule.
2
Following a single round of glycolysis, pyruvate oxidation, and the citric acid cycle, how many carbons from the original glucose molecule are released as CO2?
2
During alcoholic fermentation, NAD+ is regenerated by the reduction of acetaldehyde to _______.
ethanol
Compared with fermentation, the aerobic pathways of glucose metabolism produce:
more oxidized coenzymes.
less CO2.
pyruvate.
more ATP.
fewer protons for pumping in mitochondria.
more ATP
Glucose is a ____ -carbon molecule
6
The synthesis of ATP from ADP and Pi is a(n) _______ reaction. In mitochondria, ATP synthesis is driven by the flow of _______ down the concentration and electrical gradient established by _______.
endergonic; protons; the electron transport
The ATP synthase is an example of a(n):
peripheral carrier protein.
integral carrier protein.
peripheral channel protein.
integral channel protein.
integral channel protein
The concentration of H+ ions inside the intermembrane space is _________ the concentration of H+ ions inside the mitochondrial matrix.
higher than
Triglycerides are major energy storage molecules. How is the complete oxidation of triglycerides to CO2 and water related to the oxidation of glucose?
They are unrelated.
Pyruvate is an intermediate in the breakdown of both glucose and triglycerides.
Acetyl CoA is an intermediate in the breakdown of both glucose and triglycerides.
Only glucose oxidation uses the glycolytic pathway.
Acetyl CoA is an intermediate in the breakdown of both glucose and triglycerides.
Which of the following statements about membrane phospholipids is FALSE?
They flip-flop from one side of the membrane to the other.
They have hydrophobic tails.
They have hydrophilic heads.
They move around freely in the membrane.
They flip-flop from one side of the membrane to the other.
The cells walls of bacteria are composed of:
peptidoglycan.
Osmosis is:
the diffusion of water across membranes.
Membranes:
display only hydrophilic characteristics
have a hydrophilic exterior and a hydrophobic interior
display only hydrophobic characteristics
have a hydrophobic exterior and a hydrophilic interior
have a hydrophilic exterior and a hydrophobic interior
Membranes may:
be electrically excitable.
transduce signals.
organize chemical reactions.
transform energy.
All answers correct
When the concentration of water inside a cell is at a lower concentration than the concentration outside the cell, the outside solution is said to be __________ to the inside solution.
hypotonic
The major factor limiting cell size is the:
concentration of water in the cytoplasm.
need for energy.
presence of membrane-enclosed organelles.
ratio of surface area to volume.
composition of the plasma membrane.
ratio of surface area to volume
When the concentration of water inside a cell is higher then the concentration of water outside a cell, the inside solution is said to be ___________ to the outside solution.
hypotonic
Cells are tremendously diverse. However all cells share some common characteristics. Which of the following is not one of these characteristics?
All cells contain ribosomes, the protein synthetic machinery.
All cells protect their genetic material in a nucleus.
All cells store their genetic information in DNA.
All cells are enclosed by a plasma membrane that separates the internal cellular environment from the external environment.
All cells protect their genetic material in a nucleus.
When the concentration of water inside a cell is higher than the concentration outside a cell, the outside solution is said to be ___________ to the inside solution.
hypertonic
Dynein motor proteins travel on which cytoskeletal filament?
microtubules
Which structure is involved with the movement of organelles within a cell?
microtubules
When GDP is bound to G-proteins, the G-protein is:
inactive
When GTP is bound to G-protiens, the G-protein is:
active
G-proteins are activated by _______ , and inactivated by _______.
GTPases; exchange of GTP for GDP
GTPases; exchange of GDP for GTP
exchange of GDP for GTP; GTPases
exchange of GTP for GDP; GTPases
exchange of GDP for GTP; GTPases
The endoplasmic reticulum is directly connected to:
the nucleus
Actin is used to manufacture:
microfilaments
Steroids are:
effector moelcules
signaling molecules
second messengers
signal receptors
signaling molecules
Proteins that have sugar molecules covalently attached to them are called:
proteoglycans
glycoproteins
peptidogylcans
saccharopeptides
glycoproteins
Which of the following membranes are continuous?
The plasma membrane and the membrane of the lysosome.
The outer nuclear membrane and the membrane of the endoplasmic reticulum.
The membrane of the endoplasmic reticulum and the trans-Golgi membrane.
The membrane of the endoplasmic reticulum and the cis-Golgi membrane.
The outer nuclear membrane and the membrane of the endoplasmic reticulum.
What is the metabolic fate of pyruvate in anaerobic muscle?
It is decarboxylated.
It is converted to ethanol.
It is reduced to lactate.
It is converted to acetylCoA.
It is oxidized.
It is reduced to lactate.
(lactic acid)
Acetyl CoA is:
formed in the cytoplasm by the oxidation of glucose.
used for the synthesis of fatty acids.
formed within mitochondria by the reduction of fatty acids.
formed within mitochondria by the reduction of pyruvate
used for the synthesis of fatty acids.
Which of the following molecules does not contain a high energy bond?
NADH+
O2
Acetyl-CoA
FADH2
ATP
O2
NAD+ is:
present only in mitochondria.
a type of organelle.
a part of ATP.
formed in the reaction that produces ethanol.
a protein.
formed in the reaction that produces ethanol
The electron transport chain occurs in:
the cytosol.
the matrix of the mitochondria.
the inner membrane of the mitochondria.
the outer membrane of the mitochondria
the inner membrane of the mitochondria
The energy needed by ATP synthase to catalyze the formation of ATP is supplied by:
a proton gradient
In yeast, the anaerobic catalysis of a single molecule of pyruvate yields how many molecules of CO2?
1
The aerobic metabolism of a single molecule of glucose will have a net yield of how many ATP molecules?
32
True or false: Channel proteins can move a solute across a membrane in either direction.
True
Which of the following proteins powers both the movement of cilia and vesicles within a cell?
Dynein
Myosin
Keratin
Actin
Dynein
Facilitated diffusion:
is carried out by peripheral membrane proteins.
can transport a molecule against its concentration gradient.
is carried out by integral transmembrane proteins.
requires ATP hydrolysis
is carried out by integral transmembrane proteins.
Which one of the following is not a function of exocytosis?
Lysosome formation
Secretion of cell wall materials in plants
Secretion of digestive enzymes in the pancreas
Neurotransmitter secretion
Lysosome formation
Membranes:
display only hydrophilic characteristics
display only hydrophobic characteristics
have a hydrophilic exterior and a hydrophobic interior
have a hydrophobic exterior and a hydrophilic interior
have a hydrophilic exterior and a hydrophobic interior
The cytoskeleton consists of:
microtubules, intermediate filaments, and microfilaments.
Which of the following proteins powers both the movement of cilia and vesicles within a cell?
Dynein
Myosin
Keratin
Actin
Dynein
Thylakoids are features of:
chloroplasts
Nucleic acids would not be found in which structure?
Plant vacuoles
Which statement about oxidative phosphorylation is NOT true?
It is the formation of ATP by the electron transport chain.
It takes place in mitochondria.
It is brought about by chemiosmosis.
Its functions can be served equally well by fermentation.
It requires aerobic conditions.
Its functions can be served equally well by fermentation.
The citric acid cycle:
takes place in the mitochondrion.
Glycolysis occurs in:
the matrix of the mitochondria.
the cytosol.
the inner membrane of the mitochondria.
the outer membrane of the mitochondria.
the cytosol
oxidation and reduction
always occur together
Which of the following Complexes of the mitochondrial electron transport chain accepts electrons from FADH2?
Complex II
Complex IV
Complex III
Complex I
Complex II
Nuclear pore complexes breach:
both nuclear membranes
Which of the following is not produced by glycolysis?
CO2
ATP
pyruvate
NADH+
CO2
Fermentation:
takes place in the mitochondrion.
prevents glycolysis.
requires lactic acid.
takes place in all animal cells.
does not require O2.
does not require O2
T or F: Pyruvate is a protein
False
Which of the following Complexes of the mitochondrial electron transport chain does NOT accept electrons from NADH?
Complex IV
Complex III
Complex I
Complex II
Complex II
In yeast, the anaerobic metabolism of a single molecule of glucose will have a net yield of how many ATP molecules?
2
Due to its ability to carry electrons and free energy, _______ is the most common electron carrier in cells.
ADP
ATP
NAD+
H+
NAD+
The entry of which molecule initiates the citric acid cycle?
oxaloacetate
pyruvate
aceytl-CoA
glucose
Aceytl-CoA
Which of the following is not a second messenger?
calcium
cAMP
ATP
adenylyl cyclase
diacylglycerol (DAG)
ATP
and
adenylyl cyclase
Steroids bind to their receptors:
in the cytosol
How is entry into the nucleus through the nucleopore and transport across the plasma membrane by a channel similar?
Transport through both the nucleopore and a channel requires ATP hydrolysis,
Both the nucleopore and the channel transport molecules through two bilayers.
Both the nucleopore and the channel create hydrophilic tunnels through which molecules can pass.
Both the nucleopore and channels can transport large molecules.
Both the nucleopore and the channel create hydrophilic tunnels through which molecules can pass.
Receptor-mediated endocytosis:
is another name for phagocytosis.
is non-specific.
results in the formation of clathrin-coated vesicles.
allows small molecules to enter cells.
results in the formation of clathrin-coated vesicles.
How can water, a polar molecule, cross biological membranes rapidly?
It is small enough to sneak through the hydrophobic part of the bilayer.
The diffusion of water is facilitated by aquaporins.
Following glycolysis, the carbon of glucose:
can be found in two pyruvate molecules and two CO2 molecules.
One molecule of pyruvate, ATP, and NADH+ can be found in each molecule.
can be found in six CO2 molecules.
can be found in two pyruvate molecules.
can be found in two pyruvate molecules.
Which of the following statements about second messengers is FALSE?
Second messengers are catalytic molecules.
Second messengers usually trigger a rapid but transient response.
Second messengers represent an amplified signal within the cell.
All second messengers are freely diffusible.
Second messengers are catalytic molecules.
Which class of macromolecules cannot be found in any component of a membrane?
carbohydrate
protein
lipid
nucleic acid
nucleic acid
The complete oxidation of pyruvate by yields how many molecules of CO2?
3
