Chapter 11 AP bio
A small molecule that specifically binds to another molecule usually a larger one a) is called a ligand b) seldom is involved and hormonal signaling c) is called a signal transducer d) usually terminates a signal reception e) is called a polymer
A
Which is true of transcription factors? a) they control which genes are expressed b) they are needed to regulate the synthesis of lipids in the cytoplasm c) they regulate the synthesis of DNA in response to a signal d) some transcribe ATP into cAMP e) they initiate the epinephrine response in animal cells
A
Adenylyl cyclase has the opposite effect of which of the following? a) GTPase b) phosphodiesterase c) protein phosphatase d) phosphorylase e) protein kinase
B
Chemical signal pathways a) operate in animals, but not in plants b) often involve the binding of signal molecules to a protein on the surface of a target cell c) involve the release of hormones into the blood d) use hydrophilic molecules to activate enzymes e) are absent in bacteria, but are plentiful in yeast
B
Consider this pathway: epinephrine -> G protein-coupled receptor -> G protein -> adenylyl cyclase -> cAMP. Identify the second messenger. a) G protein coupled receptor b)cAMP c) Adenylyl cyclase d) GTP e) G protein
B
G proteins and G protein linked receptors a) are found only in bacterial cells, embedded in the cells plasma membrane only b) are thought to have evolved very early, because of their similar structure and function in a wide variety of modern organisms c) are found only in animal cells, and only in bedded in or located just beneath the cells membrane d) probably evolved from an adaptation of the citric acid cycle e) are not widespread in nature and were unimportant in the evolution of eukaryotes
B
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because Athey always lead to the same cellular response. B.they amplify the original signal manyfold. Cthe number of molecules used is small and fixed. D.they are species specific. E.they counter the harmful effects of phosphatases.
B
Which of the following describes cell communication systems? a). communicating cells are usually close together b) in response to a signal, the cell may alter activities by changes in cytosol activity or in transcription of RNA c) lipid phosphorylation is a major mechanism of signal transduction d) most signal receptors are bound to the outer membrane of the nuclear envelope e) cell signaling evolved more recently than systems such as the immune system of vertebrae's
B
Which of the following is a chemical messenger that passes through The plasma membrane of cells and has receptor molecules in the cytoplasm? a) epinephrine b) testosterone c) cAMP d) Insulin
B
Caffeine is an inhibitor of phosphordiesterace. Therefore, the cells of a person who has recently consumed coffee would have increased levels of a) GTP b) phosphorylated proteins c) cAMP d) activated G proteins e) adenylyl cyclase
C
From the perspective of the cell receiving the message, the 3 stages of cell signaling are a) The alpha beta and gamma stages b) Signal reception, nucleus disintegration, and new cell generation c) Signal reception, signal transduction and cellular response d) The paracrine local and synaptic stages e) Signal reception cellular response and cell division
C
Protein phosphorylation is commonly involved with all the following except a) enzyme activation b) regulation of transcription by extracellular signal molecules c) activation of G protein-coupled receptors d) activation of receptor tyrosine kinases e) activation of protein kinase molecules
C
What would be true for the signaling system in an animal cell that lacks the ability to produce GTP? a) it could activate only the epinephrine system b) it would be able to carry out the reception and transduction, but would not be able to respond to a signal c) it would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane d) only A and C are true e) A, B, and C are true
C
Apoptosis involves all but which of the following? A) fragmentation of the DNA B) cell-signaling pathways C) activation of cellular enzymes D) lysis of the cell E) digestion of cellular contents by scavenger cells
D
Paracrine signaling a) requires nerve cells to release a neurotransmitter into the Synapse b) involves mating factors attaching to target cells and causing production of new paracrine cells c) has been found in plants but not animals d) involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular fluid e) occurs only in paracrine yeast cells
D
The activation of receptor tyrosine kinases is characterized a) A phosphorylation cascade b) GTP hydrolysis c) Channel protein shape change d) dimerization and phosphorylation e) IP3 binding
D
The general name for an enzyme that transfers phosphate groups from an ATP to a protein is a) phosphorylase b) protease c) ATPase d) phosphatase e)protein kinase
E
Which of the following is (are) true of ligand gated ion channels a) they open or close in response to a chemical signal b) they lead to changes in ion concentration in cells c) they are important in the nervous system d) only A and B are true e) A, B, and C are true
E
Which of the following are chemical messengers that pass through the plasma membrane of cells and have receptor molecules in the cytoplasm?
testosterone
