Exam 2 extra stuff Flashcards
Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell. Which of the following ions is the most abundant inside a typical mammalian cell?
K+
Several different classes of enzymes are needed for the catabolism of carbohydrates. Which of the following descriptions best matches the function of a KINASE?
- An enzyme that catalyzes the rearrangement of bonds within a single molecule
- An enzyme that catalyzes a change in the position of a specific chemical group within a single molecule
- An enzyme that catalyzes the oxidation of a molecule by removing a hydroide ion
- An enzyme that catalyzes the addition of phosphate groups to other molecules
An enzyme that catalyzes the addition of a phosphate groups to other molecules
In living cells, the gradual oxidation of glucose during cellular respiration is favored over combustion to CO2 and H2O in a single step because ______.
Energy is released stepwise, in small amounts.
The reaction cycle that uses acetyl CoA to generate electron carrier molecules needed in the electron-transport chain is important for powering the cell. Which of the names below is not one commonly used to describe this reaction?
- tricarboxylic acid cycle
- krebs cycle
- electron transport chain
- citric acid cycle
electron transport cycle
Which of the following cells rely exclusively on glycolysis to supply them with ATP?
- anaerobically growing yeast
- aerobic bacteria
- skeletal muscle cells
- plant cells
anaerobically growing yeast
In oxidative phosphorylation, ATP production is coupled to the ecents in the electron-transport chain. What is accomplished in the final electron-transfer event in the electron-transport chain?
- OH- is oxidized to O2
- pyruvate is oxidized to CO2
- O2 is reduced to H2O
- NAD+ is reduced to NADH
O2 is reduced to H2O
The final metabolite produced by glycolysis is _____.
- Acetyl CoA
- Pyruvate
- 3-phosphoglycerate
- glyceraldehyde 3-phosphate
pyruvate
K+ leak channels are found in the plasma membrane. These channels open and close in an unregulated, random fashion. What do they accomplish in a resting cell?
- they set the K+ concentration gradient to zero
- They set the membrane potential to zero
- They disrupt the resting membrane potential
- They establish equilibrium where net movement of K+ is zero
They establish equilibrium where net movement of K+ is zero
Steps 7-10 of glycolysis result in substrate-level phosphorylation. Which of the following best describes this process?
- ATP is being hydrolyzed to phosphorylate the substrate
- The energy derived from substrate oxidation is coupled to the conversion of ADP to ATP
the energy derived from substrate oxidation is coupled to the conversation of ADP to ATP.
If Na+ channels are opened in a cell that was previously at rest, how will the resting membrane potential be affected?
- the potential is not affected by NA+
- It becomes more negative
- It becomes more positive
- It is permanently reset
It becomes more positive
The concentration of H+ ions inside the mitochondrial matrix is lower than it is in the cytosol or the mitochondrial inter-membrane space. What would be the immediate effect of a membrane-permeable compound that carries are releases protons into the mitochondrial matrix?
inhibition of ATP synthesis
_____ produced in the citric acid cycle and glycolysis donates electrons to the electron-transport chain.
NADH
_____ acts as the final electron acceptor in the electron-transport chain
oxygen
The synthesis of ATP in mitochondria is also known as ______
oxidative phosphorylation
T/F: Activated carrier molecules FADH2 and NADH store heat energy for the cell to use later.
FALSE. They donate e- to the electron transport chain
T/F: Catabolism is a general term that refers to the process by which large molecules are synthesized from smaller molecules.
FALSE. Anabolism
T/F: Fuel sources, including amino acids, fats, and carbohydrates, must be converted to acetyl CoA before they can be oxidized by the citric acid cycle.
True
T/F: all electron carriers of the electron transport chain are large protein complexes that are in a fixed position within the inner mitochondrial membrane.
False – some e- carriers are mobile
Where does glycolysis take place?
cytosol
Where does the citric acid cycle take place?
mitochondrial matrix
Where does the conversion of pyruvate to activated acetyl groups take place?
In mitochondrial matrix
Where does the oxidation of fatty acids to acetyl CoA take place?
Mitochondrial matrix
Where does the oxidative phosphorylation take place?
Inner membrane of the mitochondria
T/F: Dehydrogenase enzymes catalyze the oxidation of a molecule by removing a hydride ion.
True
During glycolysis, glucose molecules are broken down to yield _____.
Pyruvate + ATP + NADH
An energy-liberating pathway is also known as ____.
catabolic
What is true of NAD+
it is a coenzyme
The nuclear membrane functions as a ____.
- means of separating nuclear and cytoplasmic constituents
- means of localization of the chromosomes within the cell
- selective barrier, allowing certain substances in or out
- means of sequestering many of the mRNA processing activities from the cytosol
(ALL THE ABOVE)
Which of the following is NOT a function associated with the cytoskeleton?
- scaffold for support and maintenance of cell shape
- anchoring site for mRNA during transcription
- cell division
- organizes the organelles within the cytoplasm
- signal transducer
anchoring site for mRNA during transcription
What characteristics best describes collagen?
- triple helix
- part of the extracellular matrix (ECM)
- most abundant protein in the ECM
In biological systems, oxidation is often described in terms of ____.
dehydrogenation
Which of the following cell junctions are essential for the proper function of intestinal epithelial cells?
- gap junctions
- adhesive junctions
- tight junctions
- desmosomes
ALL THE ABOVE
What is the best statement that best describes the role of NAD+/NADH in glycolysis?
NAD+ is used to carry electrons
Which of the following substances is required in the citric acid cycle reactions as an electron acceptor?
NAD+
Electrons are passed to the electron transport system from
NADH and FADH2
The major structural elements of the cytoskeleton are
microtubules, microfilaments, and intermediate filaments
Where does the breakdown of pyruvate occur?
mitochondrial matrix
Where does the citric acid cycle occur?
mitochondrial matrix
Where does the electron transport chain occur?
inner mitochondrial membrane
How is the H+ gradient created and how is such a gradient used to generate ATP?
The H+ electrochemical gradient is created by H+ donors such as NADH and FADH2 losing their e-, and generating a gradient.
This gradient then triggers and runs the rotary machine responsible for synthesizing ATP from ADP.
