In 1970, Frye and Edidin published research describing the mobility of plasma membrane proteins. They fused mouse and human cells together, creating a hybrid cell, and then examined the localization of mouse and human proteins over time. Initially mouse and human proteins were each restricted to one-half of the heterokaryon, but over time the mouse and human proteins mixed, with each being present over the entire cell surface. What technique did Frye and Edidin likely use to examine the mouse and human proteins? Choose one: O A. interference contrast light microscopy B. transmission electron microscopy O C. fluorescence microscopy OD. scanning electron microscopy

In 1970, Frye and Edidin published research describing the mobility of plasma membrane proteins. They fused mouse and human cells together, creating a hybrid cell, and then examined the localization of mouse and human proteins over time. Initially mouse and human proteins were each restricted to one-half of the heterokaryon, but over time the mouse and human proteins mixed, with each being present over the entire cell surface. What technique did Frye and Edidin likely use to examine the mouse and human proteins? Choose one: O A. interference contrast light microscopy B. transmission electron microscopy O C. fluorescence microscopy OD. scanning electron microscopy

Concepts of Biology

1st Edition

ISBN:9781938168116

Author:Samantha Fowler, Rebecca Roush, James Wise

Publisher:Samantha Fowler, Rebecca Roush, James Wise

Chapter3: Cell Structure And Function

Section: Chapter Questions

Problem 17CTQ: In the context of cell biology, what do we mean by form follows function? What are a least two...

See similar textbooks

Similar questions

You are interested in the mobility of two different unknown integral plasma membrane proteins—protein X and protein Y—in a cell. In one cell, you fluorescently label all the X proteins. In another cell, you label all the Y proteins. When you perform FRAP analysis on both cells, you find that most of the protein X fluorescence has recovered within 3 minutes, but recovery of the protein Y fluorescence is significantly slower. Even after 10 minutes, only 50% of the protein Y fluorescence has recovered. Describe the FRAP experimental protocol, explain what the results tell you about mobility of the X and Y proteins, and propose a possible explanation for why the mobilities of the two proteins differ.
I am studying pancreatic islet cells and have isolated, cloned, and sequenced a novel protein that you postulate has 4 transmembrane segments. What kind of experiment would allow me to test this hypothesis that there are 4 trans membrane segments?
The following image is based on real results from an influential experiment in cell biology. This experiment studied the role of the proteins Ran and importin in nuclear protein transport. The experiment used flourescently-labeled proteins containing a nuclear localization sequence (the "substrate"). Ran, importin, and GTP were either present or absent, as indicated in the figure. Cells were exposed to these different conditions and then analyzed by fluorescence microscopy. Circles are the cells' nuclei. Very light circles are the nuclei without the substrate attached. Study the figure below and then answer the questions that follow. 1. What actions does Ran perform by itself? 2. What actions does importin perform by itself? 3. How do Ran and importin act together in the nuclear import of protein? 4. Why is GTP required?
The nucleus a) has a single membrane and compartmentalizes the genetic material b) has a double membrane joined by nuclear pores, is continuous with the endoplasmic reticulum membrane, and compartmentalizes the nuclear genetic material c) has a double membrane joined by nuclear pores, is continuous with the smooth endoplasmic reticulum membrane only, and compartmentalizes the nuclear genetic material d) None of these are accurate
A group of membrane proteins can be extracted from membranes only by using detergents. All the proteins in this group have a similar amino acid sequence at their C-terminus: -KKKKKXXC (where K stands for lysine, X stands for any amino acid, and C stands for cysteine). This sequence is essential for their attachment to the membrane. What is the most likely way in which the C-terminal sequence attaches these proteins to the membrane? The cysteine residue is covalently attached to a membrane lipid. The peptide spans the membrane as an α helix. The peptide spans the membrane as part of a β sheet. The positively charged lysine residues interact with an acidic integral membrane protein.
As a researcher who studies cytoskeletal dynamics, you create a microtubule subunit that cannot hydrolyze GTP. How would the critical concentration for the minus end of a polymer formed by these mutant subunits compare to that of the minus end of a fiber formed by normal microtubule subunits? Why? How would the critical concentration for the minus end of a fiber formed by these mutant subunits compare to that of the plus end of a fiber formed by normal microtubule subunits? Why?
If cells are infected with a vesicular stomatitis virus (VSV) strain in which a viral gene (VSVG) is fused to the green fluorescent protein gene, when the chimeric protein is synthesized, what compartments will it visit and in what order before until it leaves the cell?
You are investigating a lysosomal storage disease and you discover that newly synthesized lysosome hydrolases (proteins that should be sent to the lysosome) are secreted from the cells rather than being delivered to the lysosomes (where they should normally be located). What is the most likely explanation for this finding? (Hint: what might be different about the proteins that would cause them to not end up in the correct location?)
In the lab you will prepare a dye solution to test transmembrane transport into yeast cells. The dye stock solution has a concentration of 5 mM. For your experiment, you want the dye concentration to be at 0.25 mM. You do the dilution with water. Select among the following, which of the following method(s) will give you the correct final concentration of dye? 1) adding 1 ml of stock solution to 19 ml of water. 2) making a 25-fold dilution. 3) adding 100 ml of water to 5 ml of dye stock solution. 4) diluting 3 ml of concentrated dye with water to a final volume of 60 ml. A. All methods are accurate B. only methods 1, 2 and 3 are accurate C. only methods 1, 3 and 4 are accurate D. only methods 1 and 4 are accurate E. only method 3 is accurate F. None of the methods reflect the proper dilution method.(edited) [3:16 PM]
ANSWER QUESTION A AND B. A protein was recently discovered to be located in the nucleus. However, it is uncertain whether this is a protein that permanently stays in the nucleus or a shuttling protein that stays most of the time in the nucleus. One way to resolve this question is to perform the following steps: • Fuse the cells expressing the fluorescently labeled protein in their nucleus with the cells that are not expressing it. • Treat the cells with an inhibitor of protein synthesis to prevent the synthesis of more labeled proteins. • Observe for fluorescence in the fused cell with two nuclei. a. What is the expected result if the protein stays permanently in the nucleus? b. What is the expected result if it is a shuttling protein? Explain your answer.
Suppose that you are carrying out studies of microtubule assembly via in vitro (in the test tube – not in the cell) assays. In a mixture of α-tubulin, β-tubulin, and abundant GTP, all suspended in a buffer that approximates cellular pH, you discover that you need the tubulin concentration to be at least 15 µM in order to observe any microtubule assembly. However, if you add centrosomes (including the proteins of the pericentriolar region) to your mixtures, you are able to observe microtubule assembly at concentrations of tubulin as low as 2 µM. Why does the addition of centrosomes to your mixture make such a difference in the concentration of tubulin needed to achieve assembly? At which end(s) of the microtubule would you expect addition of tubulin monomers to be occurring in your mixtures that include centrosomes? Suppose that you further altered your solution by replacing GTP with a GTP analogue that behaves like GTP in all respects, other than its ability to be hydrolyzed to…
Microtubules both in vitro and in vivo undergo dynamic instability, and this type of assembly is thought to be intrinsic to the microtubule. What is the current model that accounts for dynamic instability?