Chapters 8, 9, 10, & 11 book questions Flashcards
Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as _______ is to _______.
exergonic; endergonic
Most cells cannot harness heat to perform work because
temperature is usually uniform throughout a cell
Which of the following metabolic processes can occur without a net influx of energy from some other process?
C6H12O6 + 6 O2 —> 6 CO2 + 6 H2O
If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to
add more of the enzyme
Some bacteria are metabolically active in hot springs because
their enzymes have high optimal temperatures
If an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur?
Nothing; the reaction will stay at equilibrium
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the
H+ concentrations across the membrane holding ATP synthase
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
glycolysis
In mitochondria, exergonic redox reactions
provide the energy that establishes the proton gradient
The final electron accepter of the electron transport chain that functions in aerobic oxidative phosphorylation is
oxygen
What is the oxidizing agent in the following reaction?
pyruvate + NADH + H+ —> Lactate + NAD+
pyruvate
When electrons flow along the electron transport chains of mitochondria, which of the following changes occur?
the pH of the matrix increases
Most CO2 from catabolism is released during
the citric acid cycle
Enzymes are described as catalysts, which means that they
increase the rate of the reaction without being consumed by the reaction
The reduced form of the electron acceptor in glycolysis is
NADH
As ATP levels accumulate, negative feedback causes cellular respiration to slow down. What is the name of the enzyme that is acted on by ATP in this negative feedback look?
phosphofructokinase
Chemical energy is a type of
potential energy
Light energy is a type of
kinetic energy
The electrons stripped from glucose in cellular respiration end up in which compound?
water
In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of
ATP, CO2, and ethanol (ethyl alcohol)
The competitive inhibitor competes with the substrate for the _________ on the enzyme.
active site
The light reactions of photosynthesis supply the calvin cycle with
ATP and NADPH
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
H2O —> NADPH —> Calvin Cycle
How is photosynthesis similar in C4 plants and CAM plants?
In both cases, rubisco is not used to fix carbon initially
Which of the following statements is a correct distinction between autotrophs and heterotrophs?
Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic
Which of the following does not occur during the Calvin cycle?
release of oxygen
In mechanism, photophosphorylation is most similar to
oxidative phosphorylation in cellular respiration
Which process is most directly driven by light energy?
removal of electrons from chlorophyll molecules
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because
they amplify the original signal manyfold
Binding of a signaling molecule to which type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane?
ligand-gated ion channel
The activation of receptor tyrosine kinases is characterized by
dimerization and phosphorylation
Lipid-soluble signaling molecules, such as testosterone, cross the membranes of all cells but affect only target cells because
intracellular receptors are present only in target cells
Consider this pathway:
epinephrine —> G protein-coupled receptor —> G protein —> adenylyl cyclase —> cAMP.
Identify the second messenger.
cAMP
Apoptosis involves
- fragmentation of the DNA
- cell-signaling pathways
- activation of cellular enzymes
- digestion of cellular contents by scavenger cells
Apoptosis does not involve
lysis of the cell
Which observation suggested to Sutherland the involvement of a second messenger in epinephrine’s effect on liver cells?
Glycogen breakdown was observed only when epinephrine was administered to intact cells
Protein phosphorylation is commonly involved with all of the following EXCEPT
activation of G protein-coupled receptors
Protein phosphorylation is commonly involved with
- regulation of transcription by extracellular signaling molecules
- enzyme activation
- activation of receptor tyrosine kinases
- activation of protein kinase molecules
