When cells respond to an extracellular signal, they most often convert the information from one form to another. This process is called:
Many of the extracellular signal molecules that regulate inflammation are released locally at the site of infection. What form of cell-to-cell signaling is being used?
When the hormone insulin is released into the bloodstream, what form of cell-to-cell signaling is being used?
Which type of receptors do steroid hormones employ?
GTP binding proteins, which act as molecular switches inside cells,
are active when GTP is bound
GPCRs are often referred to as seven-pass transmembrane receptors because they have:
a polypeptide chain that crosses the lipid bilayer seven times
Which of the following is not a small intracellular signaling molecule(second messenger)?
When activated by a GPCR, adenylyl cyclase:
converts ATP to cAMP
How does IP3 function in the inositol phospholipid pathway?
it binds to and opens Ca2+ channels that are embedded in the ER membrane, releasing Ca2+ into the cytosol
Mutant Ras poteins, which are found in many cancer cells, can't hydrolyze their bound GTP to GDP, and therefore:
can't turn themselves off
When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway?
Testosterone functions inside a cell by
binding with a receptor protein that enters the nucleus and activates specific genes
One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups to itself, and then activating relay proteins. Which type does this?
receptor tyrosine kinases
In general, signal transmission through phosphorylation of a series of proteins:
brings a conformational change to each protein
In cell signaling, "cross-talk" refers to what?
Relay molecules activated by 2 different receptors affect the same pathway
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
An inhibitor of which of the following could be used to block the release of calcium from the endoplasmic reticulum?
Which type of signaling has the shortest signaling distance?
Sugars derived from food are broken down by:
glycolysis, the citric acid cycle, and oxidative phosphorylation
The end products of glycolysis are:
pyruvate, ATP, and NADH
Which of the following is NOT required for glycolysis to occur?
Under anaerobic conditions, which metabolic pathway regenerates the supply of NAD+ for glycolysis?
What does it mean for a bond to be "high energy," such as between phosphate groups in ATP?
The hydrolysis of such a bond is particularly energetically favorable
One function of both alcohol fermentation and lactic acid fermentation is to:
oxidize NADH to NAD+
Although the citric acid cycle itself does not use O2, it requires a functioning electron transport chain (which uses O2) in order to regenerate which molecule for further use in the citric acid cycle?
In eukaryotic cells, what is the final electron acceptor in the electron transport chain?
The complete oxidation of glucose to H2O and CO2 produces about how many molecules of ATP per molecule of glucose?
What is the main chemical energy currency in cells?
Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water?
oxidative phosphorylation (chemiosmosis)
Which of the following is NOT true of mitochondria?
They are replaced by chloroplasts in plants
In a eukaryotic cell, where are most of the proteins for the electron transport chain located?
In the mitochondrial inner membrane
The electron transport chain pumps protons:
from the matrix to the intermembrane space to the matrix
When protons move down their electrochemical gradient into the mitochondrial matrix, they:
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
Where is oxygen created in the photosynthetic process?
What main products generated from the light-dependent reactions in plant cells are used to help make sugar
ATP and NADPH
In the electron transport chain in chloroplasts, which molecule serves as the final electron acceptor?
When a chlorophyll molecule captures light energy, what form does the energy take?
In photosynthesis, what drives generation of ATP by ATP synthase?
A proton gradient across the thylakoid membrane
When an electron is removed from the reaction center of photosystem II, how is the missing electron then replenished?
With an electron removed from water
What provides the fuel to convert CO2 into sugars in chloroplasts
ATP and NADPH generated in the photosynthetic light reactions
What is the correct order of processes in generating the maximum amount of ATP from glucose?