BIO 1140 Study Guide - Midterm Guide: Lipid Raft, Sphingolipid, Cell Membrane

62 views1 pages

silversnail586

6 Apr 2018

School

University of Ottawa

Department

Biology

Course

BIO 1140

Professor

Caroline Petit- Turcotte

For unlimited access to Study Guides, a Grade+ subscription is required.

Document Summary

Describe the relevant structural aspects of lipid rafts, and then discuss two advantages they provide in the context of cellular signalling. (5 marks) The lipid raft is an area of the plasma membrane that had long and saturated fatty acid chains. This allows for the big transmembrane proteins to fit in the membrane. The saturation of the fatty acids contributed to a decrease in fluidity of the membrane; however, the addition of cholesterol around the transmembrane proteins allows the proteins to change conformation when a ligand binds to them. In this way the sphingolipids and cholesterol contribute to a highly ordered micro domain that allows local fluidity of the membrane. One advantage of the lipid raft is that is allows the membrane to accommodate for the large transmembrane proteins which would otherwise be too large to it in the membrane.

Related Questions

What is the relationship of:

- glycerol and phospholipids

- heads and tail cartoon and membrane phospholipids

- condensation reactions and synthesis of membrane phospholipids

- membrane fluidity and cell function

- length of fatty acid chains in phospholipids and membrane fluidity

- saturation of fatty acid chains in phospholipids and membrane fluidity

- amphipathic nature of cholesterol and its ability to interact with membrane phospholipids

- lipid rafts and membrane fluidity

- ether linkages in phospholipids and response to acidic conditions

- ester linkages in phospholipids and response to acidic conditions

- strong detergent such as SDS and membrane proteins

- weak detergent such as Triton X-100 and membrane proteins

- detergents and their effect on lipid bilayers

ivoryrabbit483

A set of erythrocytes is placed in a beaker of 0.9% NaCl.Nothing appears to happen to the cells. Why?

0.9% NaCl is hypertonic to the cells.

Sodium blocks the movement of water.

0.9% NaCl is hypotonic to the cells.

0.9% NaCl is iostonic to the cells.

water has not moved at all.

Question 2

Select one answer.

Which substance would be mostlikely to pass through a lipid bilayer/plasma membrane withoutembedded proteins?

water

a steroid hormone

a large fatty acid

a large peptide hormone

a sodium ion

Question 3

Select all that apply.

Which of the following can cross the cellâs plasmamembrane without the assistance of protein transporters?Select all that apply.

large polar molecules

positively charged ions

small hydrophobic molecules

gasses

Question 4

Select one answer.

Biological Membranesare:

symmetrical.

impermeable.

static.

dynamic.

Question 5

Select one answer.

How does the selectivepermeability of the membrane help the cell.

This allows the cell to maintain the proper shape.

This allows the cell to regulate what enters and exits

This allows the cell to maintain a constant temperature.

All of these

Question 6

Select one answer.

What is the role of carbohydratesin the plasma membrane?

cellular identification

adhesion

transport materials across the membrane

help maintain fluidity

Question 7

Select one answer.

Which component of the plasmamembrane has the widest variety of functions?

sterols

carbohydrates

phospholipids

proteins

Question 8

Select one answer.

All of the following have aneffect on the fluidity of a membrane except:

interactions among fatty acids in the core of the bilayer

the cholesterol content

the ratio of saturated to unsaturated fatty acids

the presence of integral proteins in the membrane

burgundyelk45

Cholesterol is transported in the bloodstream in lipoproteinparticles. There are several classes of lipoprotein particles, butone of the most important classes is called Low-densitylipoproteins (LDL). LDL particles are composed of a single moleculeof a large protein called apolipoprotein, as well as thousands ofcholesterols molecules and phospholipids. Part of theapolipoprotein forms the surface of the particles and faces theaqueous phase, while other parts face the hydrophobic interior ofthe particle where they interact with cholesterol and thehydrophobic tails of the phospholipids. When cells need additionalcholesterol, they produce a receptor protein on the surface oftheir plasma membrane that binds to the apolipoprotein andinitiates the uptake of LDL particles into the cell via a processcalled endocytosis.

1. What is the likely reason that LDL particles are used totransport cholesterol in the blood stream?

a. Cholesterol in LDL particles easily inserts into lipidbilayers

b. Cholesterol id largely insoluble in aqueous solutions

c. Cholesterol is synthesized within LDL particles

d. LDL particles can form lipid rafts in the lipid bilayer

2. What is the most likely location of phospholipids in LDLparticles?

a. Bound to the hydrophilic domain of apolipoprotein

b. In the lipid bilayer that surrounds LDL particles

c. On the surface interacting with the aqueous environment aswell as interacting with the hydrophobic core of the particle

d. Within the hydrophobic core of the particle

3. What best describes the class of protein that apolipoproteinbelongs to?

a. Amphipathic proteins

b. Cell surface proteins

c. Membrane associated protein

d. Multipass membrane proteins

4. What kind of molecule on the surface of the cell would bemost likely to serve as a receptor for LDL particles?

a. a cholesterol binding protein

b. a glycolipid

c. a phospholipid

d. trans membrane protein

5. What conditions would be most likely to trigger increaseduptake of LDL particles by cells?

a. increased glycolipid synthesis

b. increased plasma membrane growth

c. increased protein secretion

d. increase protein synthesis

BIO 1140 Study Guide - Midterm Guide: Lipid Raft, Sphingolipid, Cell Membrane

Document Summary

Get access

Related textbook solutions

Molecular Cell Biology

Biology: Science for Life with Physiology

Concepts of Biology

Biology

Essentials of Biology

Related Documents

BIO 1140 Lecture Notes - Lecture 1: Lipid Raft, Sphingolipid, Phospholipid

BIO 1140 Lecture Notes - Lecture 12: Signal Transduction, Lipid Raft, Response Element

BIO 1140 Lecture Notes - Lecture 6: Homeostasis, Gluconeogenesis, Phosphatidylinositol

Related Questions