6. A control phospholipid membrane is isolated in which the phospholipid tails all havean 18-C chain length and are comprised of a 50:50 mixture of saturated andunsaturated tails. In addition, about 25% of the lipids are fluorescently labeled onthe head groups.a) Draw a single plot of Fluidity vs. Temperature that contains the expected curvesfor:Control phospholipid (line- -)Control supplemented with 18-C saturated phospholipids (dashed line -Control supplemented with 16-C chain length (dotted line • • • • • • )b) Draw a single plot of the Fluorescence Intensity vs. Time that contains theexpected curves of a Fluorescence Recovery After Photobleaching (FRAP) usingthe same samples as in (a) above. The FRAP experiment is conducted at thesame temperature for each sample (which is the Tm of the of the controlphospholipid).

Phospholipids are major membrane lipids and present as a bilayer structure. It is consist of…

Answered: 6. A control phospholipid membrane is…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Proteoglycan aggregates in tissues form hydrated, viscousgels. Can you think of any obvious mechanical reason whytheir capacity to form gels is important to cell function?[Hint: Liquid water is virtually incompressible.]
Draw a hydropathy plot and a 2D protein cartoon for a protein that passes through the lipid bilayer 6 times..
A protein engineer was tasked to design a polypeptide chain that has an a-helical stretch that needs to span a lipid bilayer. The lipid bilayer has an average thickness of 40 angstroms. How many amino acid residues should the engineer include in the a-helical portion of the polypeptide chain that she is designing so that the helical portion will most closely match the thickness of the lipid bilayer? O 20 O 27 O 30 O 10
a. You selectively label phospholipids with a fluorescent dye and perform the FRAP assay. You detect a single fluorescence molecule move 100 micrometre into the photobleached area in 2.5 seconds. What is the diffusivity constant for this phospholipid? b. Increasing the ratio of unsaturated to saturated phospholipids in a biological membrane increases membrane fluidity. Describe how the FRAP photobleaching and recovery curves would differ between membranes with 63% and 41% unsaturated phospholipids. c. Draw the FRAP photobleaching and recovery curves for your answer in b. d. What does the “immobile fraction” in a FRAP experiment suggest (see diagram)?
13. Which of the following statements about membrane phospholipids is/are true? a) They are oriented within biological membranes with polar head groups facing the outsides of the membrane. b) Only if assisted by the appropriate enzymes, phospholipids in aqueous solution will form themselves into bilayers, which seal their edges by forming droplets. c) They can have different shapes depending on the presence of double bonds in their fatty acid tails. d) a and c e) a, b and c
A sample mixture consists of three proteins with the following properties: Protein A MW (kDa) 200 Amino acid composition 40% nonpolar, 60% polar B 45 20% nonpolar, 80% polar C 98 85% nonpolar, 15% polar IpH 9 3 5 1. If the mixture is subjected to ammonium sulfate precipitation, which protein will precipitate out first? [Select] 2. If the mixture is subjected to isoelectric focusing, which protein will stop moving nearest to the positive electrode? [Select] 3. If the mixture is subjected to cation-exchange chromatography using a buffer at pH 7, which protein will bind to the resin? [Select] 4. If the mixture is subjected to SDS-PAGE, which protein will be at the bottommost portion of the gel? [Select] * Previous Nex
The plasma membrane of E. coli is about 75% protein and 25% phospholipid by weight. How many molecules of membrane lipid are present for each molecule of membrane protein? Assume an average protein Mr of 50,000and an average phospholipid Mr of 750. What more would you need to know to estimate the fraction of the membrane surface that is covered by lipids?
(c) The tube and cylinder diagram to the right illus- trates schematically the potassium channel protein from a bacterium. This channel protein consists of four identical polypeptide chains each comprised of 119 residues. The cyan ribbon illustrates only two of the polypeptide chains. The relative positions of 4 α-helices, one from each poly- peptide chain, are shown as cylinders. The red sphere in the central part of the diagram shows the position of a potas- sium ion identified by X-ray structure analysis. A cesium ion (green sphere) was also found to be stabilized in the same position when cesium chloride was introduced into the crys- tals. The cylinders each represent an α-helix running from Tyr62 to Thr74. Considering the position of the potassium ion, in- dicate on one of the cylinders at which end of the cylinder residue Tyr62 is found and at which end residue Thr74 is found. Explain the basis of your answer? Ala23 Thr119 (d) The N- and C-terminal residues of one of the…
A researcher is isolating proteins from a cell via different techniques. They find that when the cell is ground with a blender, all of the proteins in the cell can be extracted. However if instead the cell membranes are agitated in a 1.2 M KCl mixture, only about 70% of the total protein is extracted.What class of membrane proteins are in this soluble extract and what forces normally hold them to the membrane?What class of membrane proteins are the 30% of proteins that remain behind, and what forces hold these proteins in the membrane? If a solution of ionic solids was not available, what other solvent systems could be used to extract these proteins?
The activity of a pore-forming membrane protein, PorinA1, was tested in different lipid bilayers at 60 °C. Each bilayer is composed of a single type of phosphoglyceride. The four different phosphoglycerides used are shown in the table below together with the corresponding average hydrophobic thickness of the bilayer formed: Phosphoglyceride Bilayer hydrophobic thickness ( A) Dilauroylphosphatidylcholine (DLPC) 30.7 Dimyristoylphosphatidylcholine (DMPC) 34.2 Dipalmitoylphosphatidylcholine (DPPC) 38.1 Distearoylphosphatidylcholine (DSPC) 42.2 PorinA1 is found to have the greatest activity when embedded in DPPC lipid bilayers. Which of the following values (in A) would be the best estimate for the length of the hydrophobic region of PorinA1? O 38 O 51 O 31 O 42 O 38
List the following compounds in order of increasing lipid bilayer permeability: RNA, Ca2+, glucose, ethanol, n2, water.
How many copies of a protein need to be present in a cell in order for it to be visible as a band on an SDS gel? Assume that you can load 100 µg of cell extract onto a gel and that you can detect 10 ng in a single band by sil ver staining the gel. The concentration of protein in cells is about 200 mg/mL, and a typical mammalian cell has a volume of about 1000 μm³ and a typical bacterium a vol ume of about 1 µm³. Given these parameters, calculate the number of copies of a 120-kd protein that would need to be present in a mammalian cell and in a bacterium in order to give a detectable band on a gel. You might try an order-of-magnitude guess before you make the calcula tions.

SEE MORE QUESTIONS

Recommended textbooks for you

Biochemistry

ISBN:

9781319114671

Author:

Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:

W. H. Freeman

Lehninger Principles of Biochemistry

Biochemistry

ISBN:

9781464126116

Author:

David L. Nelson, Michael M. Cox

Publisher:

W. H. Freeman

Fundamentals of Biochemistry: Life at the Molecul…

Biochemistry

ISBN:

9781118918401

Author:

Donald Voet, Judith G. Voet, Charlotte W. Pratt

Publisher:

WILEY

Biochemistry

ISBN:

9781319114671

Author:

Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:

W. H. Freeman

Lehninger Principles of Biochemistry

Biochemistry

ISBN:

9781464126116

Author:

David L. Nelson, Michael M. Cox

Publisher:

W. H. Freeman

Fundamentals of Biochemistry: Life at the Molecul…

Biochemistry

ISBN:

9781118918401

Author:

Donald Voet, Judith G. Voet, Charlotte W. Pratt

Publisher:

WILEY

Biochemistry

ISBN:

9781305961135

Author:

Mary K. Campbell, Shawn O. Farrell, Owen M. McDougal

Publisher:

Cengage Learning

Biochemistry

ISBN:

9781305577206

Author:

Reginald H. Garrett, Charles M. Grisham

Publisher:

Cengage Learning

Fundamentals of General, Organic, and Biological …

Biochemistry

ISBN:

9780134015187

Author:

John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson

Publisher:

PEARSON

SEE MORE TEXTBOOKS