Indicate true (T) and false (F) statements below regarding signaling. Your answer would be a four-letter string composed of letters T and F only, e.g. TTTF. (  ) Since multicellularity evolved before the divergence of the plant and animal lineages, plants have homologs of most animal signaling proteins, such as nuclear receptors, Ras, JAK, and Notch. (  ) Receptor tyrosine kinases are the largest class of cell-surface receptors in plant cells. (  ) Animals use cyclic GMP, NO, and Ca2+ for cell signaling. (  ) Receptor tyrosine kinases are the most abundant type of receptors signaling proliferation in animal cells.

The rod photoreceptors in the eye are extremely sensitive to light. The cells sense light through a signal transduction cascade involving light activation of a GPCR that activates a G protein that activates cyclic GMP phosphodiesterase. How would you expect the addition of the following drugs to affect the light-sensing ability of the rod cells? Explain your answers. a drug that inhibits cyclic GMP phosphodiesterase a drug that is a nonhydrolyzable analog of GTP

v-SNAREs and t-SNAREs mediate the recognition of a vesicle at its target membrane so that a vesicle displaying a particular type of v-SNARE will only fuse with a target membrane containing a complementary type of t-SNARE. In some cases, v-SNAREs and t-SNAREs may also mediate the fusion of identical membranes. In yeast cells, right before the formation of a new cell, vesicles derived from the vacuole will come together and fuse to form a new vacuole destined for the new cell. Unlike the situation we have discussed in class, the vacuolar vesicles contain both v-SNAREs and t-SNAREs. Your friend is trying to understand the role of these SNAREs in the formation of the new vacuole and consults with you regarding the interpretation of his data.   Your friend has designed an ingenious assay for the fusion of vacuolar vesicles by using alkaline phosphatase. The protein alkaline phosphatase is made in a “pro” form that must be cleaved for the protein to be active. Your friend has designed two different strains of yeast: strain A produces the “pro” form of alkaline phosphatase (pro-Pase), whereas strain B produces the protease that can cleave pro-Pase into the active form (Pase). Neither strain has the active form of the alkaline phosphatase, but when vacuolar vesicles from the strains A and B are mixed, fusion of vesicles generates active alkaline phosphatase, whose activity can be measured and quantified (see Figure (a)).   Your friend has taken each of these yeast strains and further engineered them so that they express only the v-SNAREs, only the t-SNAREs, both SNAREs (the normal situation), or neither SNARE. He then isolates vacuolar vesicles from all strains and tests the ability of each variant form of strain A to fuse with each variant form of strain B, by using the alkaline phosphatase assay. The data are shown in the graph in Figure (b). On this graph, the SNARE present on the vesicle of the particular yeast strain is indicated as “v” (for the presence of the v-SNARE) and “t” (for the presence of the t-SNARE).   1) What do his data say about the requirements for v-SNAREs and t-SNAREs in the vacuolar vesicles? Describe the evidence supporting your answer. 2) Is it important to have a specific type of SNARE (that is, v-SNARE or t-SNARE) on each vesicle? Describe the evidence supporting your answer.

The G1 DNA damage checkpoint ________________.  

Acetylcholine binds to a GPCR on heart muscle, making the heart beat more slowly. The activated receptor stimulates a G protein, which opens a K+ channel in the plasma membrane. Which of the following would enhance this effect of the acetylcholine?

3.  Convert 15 km to meters

Describe one of your favorite songs.

Examine the graph below carefully. Note the three regions labelled A, B, and C. The correct term for an animal that responds to environmental temperature variation in this way is .

Again referring to the same climate diagram, what is the actual evapotranspiration (AET) in December?

Photorespiration in plants releases oxygen and generates ATP.