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