|1) In yeast (Saccharomyces cerevisiae), the two sexes are called ||B) a and alpha. |
|2) In the yeast signal-transduction pathway, after both types of mating cells have released the mating factors and the factors have bound to specific receptors on the correct cells, ||A) binding induces changes in the cells that lead to cell fusion. |
|3) Which of the following is true of the mating signal-transduction pathway in yeast? ||C) Mating type a secretes a signal called a factor. |
|4) Which of the following responses would be expected in myxobacteria when nutrients are scarce? ||C) Starving cells secrete a chemical signal that simulates other cells to aggregate in the soil and form spores. |
|5) What could happen to target cells in an animal that lack receptors for local regulators? ||B) They would not be expected to multiply in response to growth factors from nearby cells. |
|6) Paracrine signaling ||A) involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular fluid. |
|7) Which of the following is true of synaptic signaling and hormone signaling? ||B) Hormone signaling is important between cells that are at greater distances apart than in synaptic signaling. |
|8) The old saying "one rotten apple spoils the whole barrel" comes from chemical signaling in plants ||D) via release of ethylene gas, a plant hormone for ripening. |
|9) From the perspective of the cell receiving the message, the three stages of cell signaling are ||C) signal reception, signal transduction, and cellular response. |
|10) A small molecule that specifically binds to a larger one ||C) is a ligand|
|11) Ligand-gated ion channels ||A) open or close in response to a chemical signal.
B) are important in the nervous system.
C) lead to changes in sodium and calcium concentrations in cells.
D) involve A and B.
E) involve A, B, and C. correct
|12) Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to ||E) a specific catalytic site of an enzyme binding to a substrate. |
|13) Most signal molecules ||D) A and B.
A) are water soluble.
B) bind to specific sites on receptor proteins in a membrane.
C) are able to pass through the plasma membrane by active transport.
D) A and B.
E) A, B, and C.
|14) Which of the following signal systems use(s) G-protein-linked receptors? ||A) neurotransmitters
B) yeast mating factors
D) A and C
E) A, B, and C
E) A, B, and C
|15) The signaling system in an animal cell lacking the ability to produce GTP
A) could activate only the epinephrine system.
B) would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
C) was discove ||B) would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. |