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| 1 | |
A response by a living cell to a change in its environment is called |
| | A) | adaptation. |
| | B) | communication. |
| | C) | evolution. |
| | D) | activation. |
| | E) | signal transduction. |
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| 2 | |
A ligand is most accurately defined as a(n): (p. 177) |
| | A) | transcription factor that promotes increased production of a particular protein in response to an environmental change. |
| | B) | receptor molecule that binds a signaling molecule sent from another cell. |
| | C) | enzyme that phosphorylates amino acids of other proteins. |
| | D) | cytoskeletal element that alters its shape to promote movement of a cell. |
| | E) | signaling molecule that binds to a cellular receptor. |
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| 3 | |
The small molecules or ions that bind surface receptors in the plasma membrane of a cell are most accurately referred to as |
| | A) | first messengers. |
| | B) | second messengers. |
| | C) | kinases. |
| | D) | phosphatases. |
| | E) | intracellular receptors. |
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| 4 | |
True or False: Cyclic AMP may be synthesized by adenylyl cyclase via ATP. |
| | A) | True |
| | B) | False |
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| 5 | |
Neurotransmitters being released from a nerve cell and binding to another nerve cell or a muscle cell would be an example of which one of the following types of cell communication? |
| | A) | endocrine signaling |
| | B) | autocrine signaling |
| | C) | paracrine signaling |
| | D) | direct intercellular signaling |
| | E) | contact dependent signaling |
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| 6 | |
Which one of the following types of cell communication is an example of autocrine signaling? |
| | A) | A hormone is distributed to target cells through the bloodstream. |
| | B) | A signaling molecule passes through a gap junction from one cell to another cell. |
| | C) | A signaling molecule is secreted by a cell and affects only that cell. |
| | D) | A membrane-bound signaling molecule on a cell interacts with a membrane-bound receptor on a neighboring cell. |
| | E) | A signal molecule that stimulates all surrounding cells and the signaling cell. |
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| 7 | |
Arrange the stages of cell signaling in order from first to last.
i. cellular response
ii. receptor activation
iii. signal transduction
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| | A) | i, ii, iii |
| | B) | ii, iii, i |
| | C) | iii, i, ii |
| | D) | iii, ii, i |
| | E) | ii, i, iii |
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| 8 | |
True or False: Ligands bind so specifically to their receptors because the interactions are covalent. |
| | A) | True |
| | B) | False |
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| 9 | |
Most types of enzyme linked receptors function by |
| | A) | interacting with G-proteins. |
| | B) | opening a channel in a biological membrane. |
| | C) | closing a channel in a biological membrane. |
| | D) | phosphorylation of a protein from ATP in their intracellular domain. |
| | E) | causing a conformational change in the ligand. |
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| 10 | |
Which of the following occurs during the signal transduction phase in G protein activation? |
| | A) | binding of signal molecule to GPCR |
| | B) | reassociation of α, β and γ subunits |
| | C) | binding of GPCR to G protein |
| | D) | promotion of cellular responses due to dissociation of activated a subunit and β/γ subunit |
| | E) | dissociation of signal molecule |
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| 11 | |
The receptor for the steroid hormone estrogen is found |
| | A) | at the extracellular face of the cytoplasmic membrane. |
| | B) | at the cytosolic face of the cytoplasmic membrane. |
| | C) | in the cytoplasm. |
| | D) | at the outer membrane of the nuclear envelope. |
| | E) | in the nucleus. |
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| 12 | |
Receptor Tyrosine Kinases can be found in |
| | A) | bacteria. |
| | B) | animals. |
| | C) | archea. |
| | D) | bacteria and animals. |
| | E) | bacteria, animals, and archea. |
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| 13 | |
An enzyme that transfers a phosphate group to another molecule is called a ________, and an enzyme that removes a phosphate group from another molecule is called a ________. |
| | A) | kinase; phosphatase |
| | B) | phosphatase; dephosphatase |
| | C) | phosphodiesterase; kinase |
| | D) | cyclase; phosphodiesterase |
| | E) | phosphatase; kinase |
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| 14 | |
True or False: Activated subunits of PKA are inactivated when they reassociate with the regulatory subunits in the presence of low levels of cAMP. |
| | A) | True |
| | B) | False |
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| 15 | |
Which one of the following statements about the use of calcium ions in signal transduction is correct? |
| | A) | Ca2+ is an example of a second messenger. |
| | B) | The Ca2+concentration in the mitochondrial matrix can be 10,000 fold higher than that of the cytoplasm. |
| | C) | Under non-stimulated conditions, the cytosolic concentration of Ca2+ is typically higher than the extracellular Ca2+ concentration. |
| | D) | Ca2+ can be moved against its concentration gradient by the energy produced by a proton or sodium pump. |
| | E) | ATP can be used as an energy source to move Ca2+ against a concentration gradient. |
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| 16 | |
Which of the following describes the cellular function of a G-protein? |
| | A) | They activate adenylyl cyclase |
| | B) | They activate phospholipase C |
| | C) | They function as transcription factors |
| | D) | They activate adenylyl cyclase and they activate phospholipase C |
| | E) | They activate adenylyl cyclase and they function as transcription factors |
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| 17 | |
Which of the following examples regarding differential gene regulation affecting cellular response is not true? |
| | A) | Different cell receptors on the same cell recognize the same molecule |
| | B) | Protein expression in intracellular signal transduction pathways can vary from cell to cell |
| | C) | Differences in affinity for the same sgnal molecule in different cell types allows different cell responses in varying signal molecule concentrations |
| | D) | Cells capable of responding to signal molecule utilize the same receptors |
| | E) | Receptors for a signal molecule may or may not be be expressed by a cell |
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| 18 | |
Active Caspase functions |
| | A) | as a protease. |
| | B) | after release from the death-inducing signaling complex. |
| | C) | as an iniator or effector caspase. |
| | D) | as a protease and after release from the death-inducing signaling complex. |
| | E) | as a protease, after release from the death-inducing signaling complex, and as an iniator or effector caspase. |
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| 19 | |
True or False: Growth factors promote cell division in plant and animal cells. |
| | A) | True |
| | B) | False |
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| 20 | |
Which of the following is/are advantages of second messengers? |
| | A) | Speed |
| | B) | Size |
| | C) | Amplification |
| | D) | Speed and Size |
| | E) | Speed, Size, and Amplification |
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