Testosterone, a lipid-soluble signaling molecule, crosses the membranes of cells throughout the body but affects only target cells because __________.
only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor
only target cells possess the cytosolic enzymes that transduce signals
intracellular receptors for testosterone are present only in target cells
only target cells retain the appropriate DNA segments
Chlorophyll molecules are in which part of the chloroplast?
Thylakoid membranes
stroma
thylakoid space
plasma membrane
the concentration of solutes in a particular cell is about 2%, but the cell contains almost no sucrose or urea. Sucrose cannot pass through the membrane of this cell, but water and urea can. Osmosis would cause this cell to shrink the most when immersed in which of the following solutions?
a hypotonic sucrose solution
a hypertonic sucrose solution
hypertonic urea solution
hypotonic urea solution
starting with one molecule of glucose, the energy containing products of glycolysis are:
2 NAD+, 2 pyruvate, and 2 ATP
2 NADH, 2 pyruvate, and 2 ATP
2 FADH2, 2 pyruvate, and 4 ATP
in the absence of oxygen, cells need a way to regenerate which compound following glycolysis?
NAD+
ethanol
carbon dioxide
Molecular oxygen (O2) has what role in aerobic cellular respiration?
it oxidizes pyruvate at the end of glycolysis
it removes a carbon only from pyruvate, producing CO2
it is the final electron acceptor at the end of the electron transport chain
it is the source of oxygen in all of the CO2 molecules produced during cellular respiration
Which of the following determines the sign of DELTA G for a reaction?
the free energy of the reactants and the free energy of the products
the affinity of the enzyme for the reactants
the enzyme concentration
the free energy of the products
the free energy of the reactants
which of the following is a correct description and sequence of events in cellular respiration?
oxidation of glucose to pyruvate; reduction of pyruvate; TCA cycle; oxidative phosphorylation
Glycolysis; education of pyruvate; TCA cycle; oxidative phosphorylation
glycolysis; oxidative phosphorylation; TCA cycles; oxidation of pyruvate
oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation
how does carbon dioxide enter the leaf?
stomata
chloroplasts
roots
thylakoids
how does a noncompetitive inhibitor decrease the rate on an enzyme reaction
by binding at the active site of the enzyme
by changing the shape of the enzyme's active site
by decreasing the activation energy of the reaction
by changing the free-energy charge of the reaction
which of the following is true for anabolic pathways
they do not depend on enzymes
they are usually highly spontaneous chemical reactions
they consume energy to decrease the entropy of the organism and its environment
the consume energy to build up polymers from monomers
enzyme activity is affected by pH because
most substrates don't function well at high or low pH
high or low pH may disrupt hydrogen bonding or ionic interactions and thus change the shape of the enzyme's active site
the binding of hydrogen ions to the enzyme absorbs energy and thus there may not be enough energy to overcome the activation energy barrier
changes in pH will cause loss of all cofactors from enzymes
when oxygen is released as a result of photosynthesis, it is a direct by-product of
the electron transfer system of photosystem I
the electron transfer system of photosystem II
splitting water molecules
chemiosomosis
approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose in aerobic cellular respiration
2
4
18
30-34
60-68
if muscle cells in the human body consume O2 faster than it can be supplied, which of the following is likely to result?
the muscle cells will have trouble making enough ATP to meet demands
the cells will not be able to carry out oxidative phosphorylation
the cells will consume glucose at an increased rate
the muscle cells will have trouble making enough ATP to meet demands and the cells will not be able to carry out oxidative phosphorylation
all of the listed events will occur
which of the following molecules is most likely to passively diffuse across the plasma membrane?
glucose
DNA
hemoglobin
when chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
it is used to power yet more cellular work
it is used to store energy as more ATP
it is transported to specific organs such as the brain
it is lost to the environment
where do the reactions of the citric acid cycle occur in eukaryotic cells?
the matrix of the mitochondrion
the cytosol
the crustal of the mitochondrion
the inter membrane space of the mitochondrion
most cells cannot harness heat to perform work because
heat is not a form of energy
cells do not have much heat; they are relatively cool
heat can never be used to do work
temperature is usually uniform throughout a cell
which of the following pairs correctly matches a membrane transport process to its primary function?
pinocytosis; the uptake of water and small solutes into the cell by formation of vesicles at the plasma membrane
phagocytosis; recreation of large particles from the cell by fusion of vesicles with the plasma membrane
exocytosis; the movement of water and solutes out of the cell by vesicle fusion with the plasma membrane
osmosis; passive diffusion of water and small solutes across a membrane
in general, the hydrolysis of ATP drives cellular work by __________.
releasing free energy that can be coupled to other reactions
yielding free phosphate
releasing heat
acting as a a catalyst
lowering the free energy of the reaction
some bacteria are metabolically active in hot springs because __________.
they are able to maintain lower internal temperature
high temperatures make catalysis unnecessary
their enzymes are completely insensitive to temperate
their enzymes have high optimal temperatures
they use molecules other than proteins or RNAs as their main catalysts
in the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of
ATP, CO2, and lactate
ATP, CO2, and ethanol (ethyl alcohol)
ATP, NADH, and pyruvate
ATP, pyruvate, and oxygen
Which of the following statements describes NAD+?
It has more chemical energy than NADH
it is oxidized by the action of hydrogenases
it is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle
it can donate electrons for use in oxidative phosphorylation
in the absence of NAD+, glycolysis can still function
the electron transport chain involved in cellular respiration is located in/on the ________.
inner membrane of the mitochondrion
cytosol
matrix of the mitochondrion
inter membrane space of the mitochondrion
non of the listed responses is corrected
which of the following does not occur during the calvin cycle?
release of oxygen
carbon fixation
oxidation of NADPH
regeneration of the CO2 acceptor
consumption of ATP
rubisco is ________.
the enzyme in C3 plants that first captures CO2 to begin the Calvin Cycle
the enzyme responsible for splitting H2O to produce O2 in photosynthesis
the enzyme that forms a 4-carbon compound in CAM photosynthesis
the 5 carbon sugar molecule that reacts with CO2 to begin the Calvin cycle
Do i need to study the matching that is on Test 2?
YES!!!!
no
