BIOC 3560 Lecture Notes - Lecture 6: Lipid Bilayer, Membrane Lipids, Ethanolamine

30 views3 pages

chocolateimpala670

7 Nov 2016

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

BIOC 3560 Lecture 6

Functions of cellular membranes

• Compartmentalization of the organism into cells

• Presentation or molecules that allow surface recognition (self/not-self tissue,

example: blood type)

• Permeability barrier that allows certain molecular and ionic compositions

inside and outside (passive, facilitated, and active diffusion)

• Communication channel between inside and outside

Composition

• Cellular membranes are defined by their lipid organization

• Have lots of proteins embedded too

• A few carbohydrates are present as modifications of both proteins and lipids

• Typical composition

o 45% lipid

o 50% protein

o 5% carbs

Lipids

• Membrane lipids are amphipathic (both polar and non-polar)

• Heads are hydrophilic (face out of the bilayer)

• Tails are hydrophobic (inside the bilayer)

• Different backbones, head groups, and fatty acids give rise to thousands of

chemically distinct lipids

• Includes phospholipids, cholesterol, glycolipids

Glycerolipids

• Most lipids have glycerol as a backbone

• Position 1 and 2 have fatty acids attached by an ester linkage

o 2 is normally – but not always – an unsaturated fatty acid

• Position 3 is occupied by a hydrophilic head group (X)

Phosphoglycerides (aka glycerophospholipids)

• In phosphoglycerides, a phosphate group is attached to the third glycerol

hydroxyl group (3rd position)

• A head group (X) is linked to the phosphates by an alcohol group

• The phosphate group imparts a -1 charge, causing a net charge of -1

o Phosphoatidic acid → X is a H

o Phosphoatidylethanolamine → X is called ethanolamine

o Phosphoatidyl choline →X is called choline

o Phosphoatidyl serine → X is called serine

** Know these and how to draw the structures

find more resources at oneclass.com

Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in

Document Summary

Composition: cellular membranes are defined by their lipid organization, have lots of proteins embedded too, a few carbohydrates are present as modifications of both proteins and lipids, typical composition, 45% lipid, 50% protein, 5% carbs. Lipids: membrane lipids are amphipathic (both polar and non-polar, heads are hydrophilic (face out of the bilayer, tails are hydrophobic (inside the bilayer, different backbones, head groups, and fatty acids give rise to thousands of chemically distinct lipids. ** know these and how to draw the structures. Glycolipids: some lipid have carbohydrate head groups, can be a single sugar, or a complex, branching sutructure. In mammals, glycosphingolipids have a sphingosine backbone, one fatty acids, and a carb head group: glcophsingolipids are found on the outer face of a membrane, example: abo blood-type system. Classification of lipidsl: storage of lipids, triacylglycerols (tag, membrane lipids (polar, phospholipids, glycerophospholipids, sphingolipids, glycolipids, sphingolipids, galactolipids.

Related Questions

I need help with pre lab 3 and 4 please :)

Experiment 8: Determination of k 45 Exp 8: Determination of Logkow Values for Four Drugs Objectives . Discover how compound polarity affects absorptiorn e Perform extractions Calculate and compare partition coefficients (Olog Kp)of four different pharmaceutical Intreduction Pharmaceutical drug design involves creating a molecule that will target a general region or site and have a therapeutic effect on the patient. Such properties depend on the drug's structure as well as its affinity for different phases in the body. When orally ingested, a drug moves from the stomach into the small intestine. From there, a drug must pass through a layer of cells before it can enter the bloodstrcam (this process is called absorption) and be distributed throughout the body. This requires crossing through largely non-polar cell membrane twice, first to enter the cell from the intestine side and then to exit the cell for entry into the bloodstream Solubility properties have a large influence on the drug's ability to navigate this trek. The drug must be polar enough to convey water solubility so that it does not precipitate out in the water solution that is well, us. For it to be absorbed into the bloodstream, however, a drug mast be non-polar enough to pass through a non-polar lipid bilayer that forms the membranes of cells. A lipid is an organic molecule that can be extracted from living tissues using non-polar organic solvents. A lipid bilayer is a thin membrane made of two lipid layers; the bilayer forms a spherical non-polar barrier separating the inside of a cell from the outside of a cell. The types of lipids that are found in cell membeanes (most commonly phospholipids (Figure 1)) are amphiphilic molecules consisting of hydrophobic ("water-fearing") and hydrophilic ("water-loving") parts. In lipid bilayers, these amphiphilic molecules arrange themselves such that the inside of the bilayer is hydrophobic while the outside (which faces the aqucous intracellular and extracellular environments) is hydrophilic (Figure 2) Figure 1: A phospholipid containing a hydrophilic head and two hydrophobic tails Figure 2: A cartoon representation ofa layer of cells separating the intestne from the bloodstream. An orally-ingested drug must pass through a cell to enter the Noodstream, cncountering both hydrophobic and hydrophilic environments in the process. Diffusion of Drug

I need help with the pre lab questions:)

Question 1

Which of the following provides the best description of adifference between prokaryotic and eukaryotic cells?.l.14.3>

The cell membrane of prokaryotic cells contains proteins, whilethe cell membrane of eukaryotic cells contains only lipids andcarbohydrates.

The DNA in eukaryotic cells is enclosed in the nucleus, whilethe DNA in prokaryotic cells is not separated from the rest of thecellÃ¢â¬â¢s contents.

Eukaryotic cells have cell walls that consist mainly of sugars,while prokaryotic cells do not.

Prokaryotic cells contain chloroplasts and mitochondria, whileeukaryotic cells do not contain specialized organelles.

Question 2

Cellular respiration is a process involving the breakdown ofglucose molecules in order to generate energy for cellularactivities. Given the general reaction below, which of thefollowing best describes the products labeled x andy?

C₆H₁₂O₆ + O₂ Ã¢â â _x___+ __y___ + energy.l.18.8>

The products are CO (carbon monoxide) andH₂O₂ (hydrogen peroxide), which thendecompose into carbon dioxide (CO₂) and water(H₂O).

The products are H2O (water) and CO₂ (carbondioxide), which then undergo anaerobic respiration.

The products are CO₂ (carbon dioxide) andH₂O (water), which then become the reactants forphotosynthesis.

The products are O₂ (oxygen) and H₂O(water), which are then used for growth and to keep the organismhydrated.

Question 3

If a researcher added a quantity of phospholipid molecules to abeaker of water, what would be most likely to happen to theorientation of the phospholipid molecules?.l.14.2>

They would break apart, and the remaining lipid tails wouldfloat up and form a layer on the surface of the water.

Their lipid tails would align within a spherical double layerwith their phosphate heads in the water inside and outside thesphere.

They would form a single-layered sphere with the phosphate headspointing outward and the lipid tails pointing inward.

Their lipid tails would adhere to the glass of the beaker andtheir phosphate heads would float in the water.

Question 4

While looking at a cell under a microscope, a scientist is ableto see a biological molecule. This molecule is a nucleic acid witha ladder structure and contains the nitrogenous bases adenine,thymine, cytosine, and guanine. Based on this information, whatconclusion can the scientist draw regarding this nucleicacid?.l.18.1>

The nucleic acid is RNA and would be found in the cellÃ¢â¬â¢snucleus.

The nucleic acid is RNA and would be found in the cytoplasm.

The nucleic acid is DNA and would be found in the cytoplasm.

The nucleic acid is DNA and would be found in the cellÃ¢â¬â¢snucleus.

Question 5

Which of the following is needed for cellular respiration tooccur?.l.18.8>

Sodium

Oxygen

Water

Nitrogen

Question 6

What would be the most likely effect if the side chain of an aminoacid group was unable to vary its structure?.l.18.4>

The organism would not be able to make and store starches.

The organism would not be able to process glucose moleculeseffectively.

The organism would not be able to regulate the creation ofspecialized cells.

The organism would not be able to make more than one type ofprotein.

Question 7

During photosynthesis, unused oxygen atoms form oxygen gas(O₂) which is released as a waste product. How did theseoxygen atoms originally enter the plant?.l.18.7>

They were part of the ATP molecules gathered by thechloroplasts.

They were part of the sugar molecules(C₆H₁₂O₆) the plant brought in forfood.

They were part of the carbon dioxide (CO₂) moleculesthat entered through the leaves.

They were part of the water molecules (H₂O) pulled inthrough the roots.

Question 8

Which of the following organelles houses DNA in eukaryoticcells?.l.14.3>

Endoplasmic reticulum

Golgi apparatus

Nucleus

Mitochondrium

Question 9

M. J. Schleiden shifted the scientific community's attention tocellular processes with his.l.14.1>

attention to disproving spontaneous generation

publication of ideas on cell generation

theories on the division of cells

claim that cells were the basic unit of all plant matter

Question 10

While the average human is able to hold his or her breath forapproximately one minute, a whale can dive for over 30 minuteswithout returning to the surface. Which of the following correctlydescribes this difference?.l.18.10>

Whales need less energy than humans.

Whales gather energy from their environment better thanhumans.

Whales are able to tolerate the products of cellular respirationbetter than humans.

Whales have a slower cellular respiration metabolism rate thanhumans.

Question 11

What can you conclude about the advantage of the cell membranehaving hydrophobic ends in the phospholipid bilayer?.l.18.3>

The cell requires the ability to digest and eliminateenzymes.

The cell requires a barrier between itself and itsenvironment.

The cell requires a means to store starches and glucose.

The cell requires a structure for eliminating waste.

Question 12

What would be the most likely outcome if the ribosomes of a cellwere damaged and stopped functioning?.l.14.3>

The cell would lose structure and shape.

Cell growth and repair would slow or stop.

Cell waste would no longer be processed.

The cell would produce more mitochondria.

ivoryjackal958

BIOC 3560 Lecture Notes - Lecture 6: Lipid Bilayer, Membrane Lipids, Ethanolamine

Document Summary

Get access

Related Documents

BIOC 3560 Study Guide - Quiz Guide: Peripheral Membrane Protein, Lipid Bilayer, Membrane Lipids

BIOC 3560 Lecture Notes - Lecture 7: Cytosol, Bacteriorhodopsin, Peripheral Membrane Protein

BIOC 3560 Study Guide - Final Guide: Peripheral Membrane Protein, Abo Blood Group System, Lipid

Related Questions