Term
| where does calvin cycle occur? |
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Definition
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Term
| The light reactions of photosynthesis use _____ and produce _____. |
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Definition
water...NADPH.
NADPH is a reactant in the calvin cycle |
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Term
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Definition
requires light directly. 2 processes- light and dark reactions
6CO2+6H2O->C6H12O6+6O2 |
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Term
| If photosynthesizing green algae are provided with CO2 containing heavy oxygen (18O), later analysis will show that all of the following molecules produced by the algae contain 18O except |
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Definition
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Term
| Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle? |
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Definition
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Term
| Where does the Calvin cycle take place? |
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Definition
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Term
| In any ecosystem, terrestrial or aquatic, what group(s) is (are) always necessary? |
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Definition
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Term
| True or false? The chemiosmotic hypothesis states that the synthesis of ATP generates a proton gradient that leads to electron flow through an electron transport chain. |
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Definition
| FALSE. The chemiosmotic hypothesis states that the flow of electrons through an electron transport chain generates a proton gradient that leads to the synthesis of ATP. |
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Term
| According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis? |
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Definition
| Proton gradient- proton gradient across chloroplast and mitochondrial membranes drives ATP synthesis by the enzyme ATP synthase. |
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Term
| Which of the following particles can pass through the ATP synthase channel? |
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Definition
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Term
| Chloroplast membrane vesicles are equilibrated in a simple solution of pH 5. The solution is then adjusted to pH 8. Which of the following conclusions can be drawn from these experimental conditions? |
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Definition
| ATP will not be produced because there is no ADP and inorganic phosphate in the solution. (This statement is true; although the proton gradient is present, ADP and inorganic phosphate are required to make ATP and were not added to the reaction.) |
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Term
| What phosphorylates ADP to make ATP? |
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Definition
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Term
| _____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment. |
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Definition
| The energy released as electrons are passed along the electron transport chain is used to pump protons into the thylakoid compartment. |
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Term
| _____ splits water into 1/2 O2, H+, and e- . |
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Definition
| Photosystem II splits water into 1/2 O2, H+, and e- . |
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Term
| Energized electrons from ____ enter an electron transport chain and are then used to reduce NADP+. |
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Definition
| Energized electrons from photosystem I are used to reduce NADP+. |
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Term
| Chlorophyll can be found in _____. |
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Definition
| The photosystems contain chlorophyll. |
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Term
| In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____. |
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Definition
| Visible light is a narrow band of the electromagnetic spectrum that lies between ultraviolet radiation and infrared radiation. |
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Term
| Which of the following is a product of the light reactions of photosynthesis? |
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Definition
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Term
| Photosynthesis is a redox reaction. This means that H2O is _____ during the light reactions and CO2 is _____ during the Calvin cycle. |
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Definition
oxidized...reduced.
During the light reactions of photosynthesis, water is oxidized, and during the Calvin cycle, carbon is reduced. |
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Term
| In the thylakoid membranes, what is the main role of the pigment molecules in a light-harvesting complex? |
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Definition
| transfer light energy to the reaction-center chlorophyll |
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Term
| What are the products of linear electron flow? |
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Definition
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Term
| Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes? |
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Definition
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Term
| What does the chemiosmotic process in chloroplasts involve? |
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Definition
| establishment of a proton gradient across the thylakoid membrane |
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Term
| Which of the following statements best describes the relationship between photosynthesis and respiration? |
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Definition
| photosynthesis stores energy in complex organic molecules, whereas respiration releases it. |
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Term
| In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during |
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Definition
| both photosynthesis and respiration |
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Term
| What is the relationship between wavelength of light and the quantity of energy per photon? |
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Definition
| they are inversely related |
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Term
| P680+ is said to be the strongest biological oxidizing agent. Given its function, why is this necessary? |
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Definition
| It obtains electrons from the oxygen atom in a water molecule, so it must have a stronger attraction for electrons than oxygen has. |
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Term
| In metabolic processes of cell respiration and photosynthesis, prosthetic groups such as heme and iron-sulfur complexes are encountered in components of the electron transport chain. What do they do? |
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Definition
| both oxidize and reduce during electron transport |
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Term
| In a cyanobacterium, the reactions that produce NADPH occur in |
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Definition
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Term
| Carbon fixation involves the addition of carbon dioxide to _____. |
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Definition
RuBP
in the calvin cycle, CO2 is added to RuBP |
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Term
| After 3-PGA is phosphorylated, it is reduced by _____. |
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Definition
NADPH
^ it supplies the electrons that reduce the phosphorylated 3-PGA |
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Term
| How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose? |
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Definition
| 6.Six carbon dioxide molecules are required to produce two G3P molecules, which can be combined to make one glucose molecule. |
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Term
| What is the primary function of the Calvin cycle? |
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Definition
| synthesize simple sugars from carbon dioxide |
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Term
| In C3 photosynthesis, the reactions that require ATP take place in |
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Definition
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Term
| Which of the following statements best represents the relationships between the light reactions and the Calvin cycle? |
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Definition
| The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, i, and NADP+ to the light reactions. |
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Term
| In the process of carbon fixation, RuBP attaches a CO2 to produce a six-carbon molecule, which is then split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle? |
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Definition
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Term
| In C3 plants the conservation of water promotes _____. |
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Definition
| photorespiration. Conserving water simultaneously reduces the amount of carbon dioxide available to the plant. |
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Term
| In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells. |
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Definition
| cytoplasm. In C4 and CAM plants carbon dioxide fixation occurs in the cytoplasm. |
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Term
| C4 plants differ from C3 and CAM plants in that C4 plants _____. |
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Definition
| transfer fixed carbon dioxide to cells in which the Calvin cycle occurs.In C3 and CAM plants carbon dioxide fixation and the Calvin cycle occur in the same cells. |
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Term
| C4 plants occur more commonly in desert conditions because _____. |
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Definition
| they can fix carbon at the lower CO2 concentrations that develop when the stomata are closed (To conserve water during hot, dry conditions, the stomata are fully or partially closed, preventing CO2 from reaching high concentrations.) |
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Term
| Photorespiration occurs when rubisco reacts RuBP with |
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Definition
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Term
| 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 |
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Definition
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Term
| CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they |
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Definition
| fix CO2 into organic acids during the night. |
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Term
| A signal transduction pathway is initiated when a _____ binds to a receptor. |
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Definition
signal molecule.
The binding of a signal molecule to a receptor initiates a signal transduction pathway. |
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Term
| A signal molecule is also known as a(n) _____. |
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Definition
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Term
| Which of these is the second of the three stages of cell signaling? |
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Definition
| transduction is the 2 of the 3 stages of cell signaling |
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Term
| Which of the following is a substance that acts at a long distance from the site at which it is secreted? |
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Definition
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Term
| Which of the following is characterized by a cell releasing a signal molecule into the environment, followed by a number of cells in the immediate vicinity responding? |
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Definition
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Term
| In the formation of biofilms, such as those forming on unbrushed teeth, cell signaling serves which function? |
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Definition
| aggregation of bacteria that can cause cavities |
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Term
| In yeast signal transduction, a yeast cell |
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Definition
| secretes molecules that result in responses by other yeast cells. |
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Term
| When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway? |
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Definition
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Term
| _____ is a signal molecule that binds to an intracellular receptor |
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Definition
| Steroids. - are nonpolar and can diffuse through the plasma membrane |
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Term
| To what does the term "ligand" refer in cell biology? |
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Definition
| Ligands are the small signaling molecules that bind specifically to corresponding protein-receptor molecules. |
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Term
| What is the function of tyrosine-kinase receptors? |
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Definition
enzymatic phosphorylation of tyrosine in the receptor protein.
(Phosphorylated tyrosine-kinase receptors then interact with relay proteins within the cell.) |
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Term
| Testosterone functions inside a cell by |
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Definition
| binding with a receptor protein that enters the nucleus and activates specific genes. |
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Term
| One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this? |
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Definition
| receptor tyrosine kinases |
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Term
| If an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system? |
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Definition
| It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. |
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Term
| When protein membrane receptors are activated, what usually happens? |
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Definition
| The receptor changes conformation after binding with signal polypeptides. |
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Term
| A signal transduction pathway is initiated when a _____ binds to a receptor. |
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Definition
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Term
| Which of these acts as a second messenger? |
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Definition
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Term
| _____ catalyzes the production of _____, which then opens an ion channel that releases _____ into the cell's cytoplasm. |
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Definition
Phospholipase C ... IP3 .... Ca2+
Phospholipase C cleaves IP3 from a membrane protein, and IP3 then binds to a calcium channel on the ER. |
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Term
| A protein kinase activating many other protein kinases is an example of _____. |
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Definition
| amplification. By activating many other molecules the initial signal is amplified. |
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Term
| Which of the following are among the most common second messengers? |
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Definition
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Term
| Which of the following would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins? |
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Definition
| receptor tyrosine kinase activity |
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Term
| Which of the following most likely would be an immediate result of growth factor binding to its receptor? |
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Definition
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Term
| Adenylyl cyclase has the opposite effect of which of the following? |
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Definition
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Term
| Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of |
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Definition
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Term
| An inhibitor of which of the following could be used to block the release of calcium from the endoplasmic reticulum? |
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Definition
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Term
| Sutherland discovered that the signaling molecule epinephrine: |
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Definition
| elevates cytosolic concentrations of cyclic AMP. |
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Term
| For the greatest advantage of multiple steps in a transduction pathway is: |
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Definition
| Having multiple steps provides for greater possible amplification of a signal. |
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Term
| The cleavage of glycogen by glycogen phosphorylase releases _____. |
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Definition
glucose-1-phosphate
Glycogen is a polysaccharide composed of glucose monomers. |
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Term
| Epinephrine acts as a signal molecule that attaches to _____ proteins. |
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Definition
| G-protein-linked receptor. |
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Term
| Which of these is a receptor for calcium ions? |
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Definition
| Calmodulin is a calcium ion receptor. |
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Term
| A toxin that inhibits the production of GTP would interfere with the function of a signal transduction pathway that is initiated by the binding of a signal molecule to _____ receptors. |
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Definition
G-protein-linked.
GTP activates G proteins. |
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Term
| Why can a signaling molecule cause different responses in different cells? |
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Definition
| The transduction process is unique to each cell type; to respond to a signal, different cells require only a similar membrane receptor. |
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Term
| GTPase activity is important in the regulation of signal transduction because it |
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Definition
| hydrolyzes GTP to GDP thus shutting down the pathway. |
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Term
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Definition
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Term
| Which of the following describes the events of apoptosis? |
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Definition
| The cell’s DNA and organelles become fragmented, the cell shrinks and forms blebs, and the cell’s parts are packaged in vesicles that are digested by specialized cells. |
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Term
| What are the functions of signal transduction pathways? |
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Definition
| Signal transduction pathways convert a signal on a cell’s surface to a specific cellular response. Signal transduction pathways amplify the effect of a signal molecule. Signal transduction pathways allow different types of cells to respond differently to the same signal molecule. |
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Term
| Which statement correctly distinguishes the roles of protein kinases and protein phosphatases in signal transduction pathways? |
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Definition
| Protein kinases regulate enzyme activity by phosphorylating or adding phosphate groups to them. Protein phosphatases dephosphorylate or remove phosphate groups from enzymes, including protein kinases. |
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Term
| The activation of receptor tyrosine kinases is characterized by |
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Definition
| dimerization and phosphorylation. |
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Term
| Why is it difficult to observe individual chromosomes with a light microscope during interphase? |
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Definition
| They have uncoiled to form long, thin strands. |
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Term
| If there are 20 chromatids in a cell, how many centromeres are there? |
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Definition
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Term
| Nucleoli are present during _____. |
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Definition
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Term
| Cytokinesis often, but not always, accompanies _____. |
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Definition
| Cytokinesis often, but not always, accompanies telophase. |
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Term
| Chromosomes become visible during _____. |
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Definition
| prophase- the chromatin fibers become discrete chromosomes. |
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Term
| Centromeres divide and sister chromatids become full-fledged chromosomes during _____. |
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Definition
| During anaphase, sister chromatids separate and daughter chromosomes migrate to opposite poles. |
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Term
| Spindle fibers attach to kinetochores during _____. |
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Definition
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