need help with biology assignment

BIOL 3410 Cell Biology fall 2021 Section 3.

Assignment 6 (34 points)

Question 1

According to your textbook, neurons have differing microtubule orientations in their axons versus dendrites. The accompanying paper (Harterink et al. 2018) is one of many published recently that sets out to address the mechanism(s) of this differential orientation. Read the paper then answer the following questions (as an aside, you can also access the paper via the URL below – it has really cool movies in it, and I recommend that you watch them).

https://jcs.biologists.org/content/131/20/jcs223107

(a) What is EBP-2::GFP and how does it function to specifically label one end of a microtubule? (4 points).

(b) What end of a microtubule does EBP-2::GFP label? (2 points)

(c) The authors make extensive use of kymographs to illustrate microtubule dynamics. Describe how kymograph data is collected and presented. (4 points)

(d) Below is a representative kymograph of EBP-2::GFP imaging. Assuming the cell body is to the left of the image below, does this EBP-2::GFP data show an axon or a dendrite? (2 points)

(e) Justify your answer. (4 points)

(f) Your textbook states that axons contain microtubules that are oriented with the plus-ends toward the exon tip whereas dendrites have a mixture of both plus and minus ends oriented outwards. Does the bulk of the data presented in this paper agree with the textbook? (2 points)

(g) Provide an explanation to the answer in (f). (4 points).

(h) Based on the data presented, what microtubule motor protein is most likely to be required for trafficking to the distal tip of a C. elegans ciliated dendrite? (2 points)

(i) The authors use femtosecond laser to sever microtubules. What was the point of that experiment? (4 points)

(j) What did the authors use to demonstrate the existence of a distal microtubule organizing center in ciliated neurons? (4 points)

(k) In APA style (look it up, don’t guess), list the citations that you used to complete this assignment. Note that posting a URL to a reference is not an acceptable answer. (2 points)