What types of transport and diffusion occur in cells?

Question 1A-B (Week 6 Analyzing): What types of transport and diffusion occur in cells? List an example of each, indicate if the listed example requires energy and, if energy is required, where does that energy come from? For each example, be sure to also compare and differentiate the size and chemical properties of the solutes crossing the membrane.

Example 1 Diffusion:

Example 2 Transport:

Question 2A-D (Week 6 Applying): You are working in a lab studying a receptor kinase that is involved in a stress response signaling pathway. Signaling molecule A binds to the receptor kinase causing dimerization and protein B is activated via phosphorylation by an activated Ras signaling protein. Protein B then phosphorylates protein C which translocates to the nucleus and activates (also by phosphorylation) protein D. Protein D is located in the nucleus and interacts with RNA polymerase to express genes involved in stress response.

A. What type (hydrophobic or hydrophilic) of signaling molecule is molecule A? How do you know? Explain your answer.

B. What type(s) of amino acids e.g. nonpolar or polar will interact with signaling molecule A? Explain your answer.

C. What type of protein is protein B? Explain your answer and describe the function of protein B.

D. Do you think there would be a change in the expression of stress response genes if there was a missense mutation in protein D? Explain your answer and the function of protein D.

Question 3 (Week 7 Understanding and Analyzing): Compare and contrast the inputs and outputs of cellular respiration and photosynthesis. Be sure to indicate if the processes are connected in terms of inputs or outputs i.e. do the outputs of photosynthesis input into cellular respiration and vice versa? Inputs and outputs to include in your description: ATP, ADP, glucose, pyruvate, acetyl-CoA, oxygen, water, sunlight, sugar and electron carriers such as NADH and NADPH.

Question 4 (Week 7 Applying): The reactions of the Calvin cycle used to be referred to as the “dark reactions” of photosynthesis and experimental evidence demonstrates that in the absence of light, the Calvin cycle shuts down. Why do you think this happens? Would you predict the Krebs cycle to also shut down in the absence of light? Why or why not?