In Class Assignment 1. Plant vacuoles are large, 90% of cell volume, which pushes the chloroplasts to the periphery of the cell. Why is this an advantage? 2. Draw and explain why chloroplasts have a double membrane (inner and outer)…note each membrane is a lipid bilayer. In which bilayer might one look for peptidoglycan? It turns out that glaucophytes (a type of freshwater algae) do retain a peptidoglycan layer. Why is this strong evidence in support of endosymbiosis? 3. Chloroplast genomes are small (~145 kb). Where did most of the genes in the original photosynthetic prokaryote go?
LB-nos promoter-NPTII-nos terminator-----35S—mcs-nos terminator-----RB Shown above is the most common type of vector used in plant transformation experiments. YFG = your favorite gene. What will happen to YFG mRNA levels in transgenic plants when… YFG is cloned into the mcs in the sense orientation? amiRNA for YFG is cloned into the mcs? What would happen if the amiRNA targeted an intron? LB-nos promoter-NPTII-nos terminator-----mcs-GUS-nos terminator-----RB How would the above construct be used to learn about YFG?
Take a close look at Figure 6.14. Explain why the plasma membrane has lots of symporters while the tonoplast has lots of antiporters? Hint: Think about what fuels secondary active transport in a plant cell.
What is the exodermis? What is the Casparian strip? Why is it beneficial to the plant to limit water uptake in older regions of the root?
= low phosphate • + = plentiful phosphate • OX = overexpression of miR399 Describe how mature miR399 levels and PHO2 5’ are affected in the root of the various lines. Why does miR399 OX in the shoot lead to high levels of miR399 in the root? root RNA levels How do these data support the hypothesis that PHO2 is a target of miR399?
454 Pyrosequencing Where does the PPi come from that initiates the fluorescent signal? What two enzymatic steps are needed for signal generation? After dATP is added, one picotiter chamber releases a signal that is 6X stronger than another cell. What happened, and how will this be read by the sequencer?
What is the molecular basis of the gnom mutant? What is the molecular basis of the mp and bd mutants? Why do they have the same phenotype? Use a diagram and words.
Apoplast Loading Why can’t sucrose enter CC/SE via the symplast pathway? What energy source fuels the uptake of sucrose into the CC/SE? Why is SUC2 expressed in source leaves?
Explain the antagonistic roles of phyA and phyB in the shade avoidance response of leaf petioles. What happens to petioles when plants are grown in high R/FR? What happens to petioles when plants are grown in low R/FR? What is the benefit of having phyA and phyB work in opposite directions?