Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's
Which curve was most likely generated from an enzyme that requires a cofactor?
It is not possible to determine whether an enzyme requires a cofactor from these data.
The oxygen consumed during cellular respiration is involved directly in which process or event?
accepting electrons at the end of the electron transport chain
For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle, what is the total number of NADH + FADH2 molecules produced?
During oxidative phosphorylation, H2O is formed. Where does the oxygen for the synthesis of the water come from?
molecular oxygen (O2)
Each time a molecule of glucose (C6H12O6) is completely oxidized via aerobic respiration, how many oxygen molecules (O2) are required?
What is proton-motive force?
the transmembrane proton concentration gradient
Which of the following couples chemiosmosis to energy storage?
In mitochondria, exergonic redox reactions
provide the energy that establishes the proton gradient.
Most CO2 from catabolism is released during
the citric acid cycle
Synthesis of ATP by the chemiosmotic mechanism occurs during
both photosynthesis and respiration.
The sugar that results from three "turns" of the Calvin cycle is glyceraldehyde-3-phosphate (G3P). Which of the following is a consequence of this?
The formation of starch in plants involves assembling many G3P molecules, with or without further rearrangements.
In an experiment studying photosynthesis performed during the day, you provide a plant with radioactive carbon (14C) dioxide as a metabolic tracer. The 14C is incorporated first into oxaloacetate. The plant is best characterized as a
Synaptic signaling between adjacent neurons is like hormone signaling in which of the following ways?
It requires binding of a signaling molecule to a receptor.
Which of the following would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins?
receptor tyrosine kinase activity
What are scaffolding proteins?
Consider this pathway: epinephrine G protein-coupled receptor G protein adenylyl cyclase cAMP. Identify the second messenger.
Where do the microtubules of the spindle originate during mitosis in both plant and animal cells?
A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. Those cells would have ____ picograms at the end of the S phase and ____ picograms at the end of G2.
The research team used the setup to study the incorporation of labeled nucleotides into a culture of lymphocytes and found that the lymphocytes incorporated the labeled nucleotide at a significantly higher level after a pathogen was introduced into the culture. They concluded that
infection causes cell cultures in general to reproduce more rapidly.
Cells that are in a nondividing state are in which phase?
Which of the following is a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex?
Which of the following triggers the cell's passage past the G2 checkpoint into mitosis?
This is the shortest part of the cell cycle:
Which of the following does not occur during mitosis?