Biochemistry Lab Midterm 2

Lipids

One of the major biomolecules in living cells that have no common structure

False

T/F proteins, carbohydrates, and nucleic acids have no common structure

Water

Lipids are organic substances that are insoluble (or sparingly soluble) in __

organic solvents, nonpolar

Lipids are soluble in __ (ether, chloroform, benzene, & acetone - all are __ solvents)

carboxyl groups, number of double bonds, number of hydroxyl groups, and length of carbon chains

This physical characteristic (solubility) as well as the chemical properties of lipids depends on the presence of __ groups, number of __, number of __ groups, and length of __

Simple, Compound, Derived

types of lipids

Simple Lipids

Are esters of fatty acids and alcohol.

Triglycerides

esters of fatty acids and glyceryl

Triglycerides

Fats and Oils are __

Waxes

esters of fatty acids and monohydric alcohol

Triglycerides and Waxes

Examples of Simple Lipids

Compound Lipids

Are esters of fatty acids and alcohol that contain another functional group.

Phospholipids

esters of fatty acids with glycerol containing an esterified phosphoric acid and a nitrogen

Glycolipids

contain an amino alcohol (sphingosine or isosphingosine) attached with an amide linkage to a fatty acid and glycosidically to a carbohydrate (sugars, amino sugar, sialic acid)

sphingosine or isosphingosine

Amino alcohol

sugars, amino sugar, sialic acid

carbohydrates

Derived Lipids

Contain hydrocarbon rings.

Steroids, Terpenes, Carotenoids

Examples of Derived Lipids

Saturated and Unsaturated Fatty Acid

Types of Fatty Acid

Saturated Fatty Acid

Is a fatty acid with a carbon chain in which all carbon-carbon bonds are single bonds.

Unsaturated Fatty Acid

Is a fatty acid with a carbon chain has at least one carbon-carbon double bond

Olive Oil

Predominantly composed of oleic acid.

Coconut Oil

Predominantly composed of lauric acid.

9; 91

Coconut Oil is _% unsaturated and _% saturated.

Lecithin

Phosphoglycerides that contains the aminoalcoholcholine

Glycerine/Glycerol

an alcohol, not a lipid

Olive Oil and Lecithin

Unsaturated Samples

Coconut Oil and Glycerine/Glycerol

Saturated Samples

translucent spot test

is also a preliminary test for the lipids which can be detected by the appearance of a translucent and greasy spot

True

T/F The lipid will not wet the filter paper, unlike water.

greasy spot

The lipid will form a __ as they are having a greasy texture that will penetrate the filter paper.

True

T/F In contrast to lipid, the spot of water will disappear from the paper whereas the spot of lipid appears as the "Translucent spot".

All positive

Result of Translucent Spot Test for Olive Oil, Coconut Oil, Lecithin, and Glycerol

Unsaturation test

is used to detect the presence of double bonds in a lipid sample.

glycerides

All the neutral fat contains __ of fatty acids.

bromine or iodine

Double bond found in the structure of unsaturated fatty acids which becomes saturated by taking up either __.

iodine

If the lipid contains more unsaturated fatty acids or more double bonds that means, it will take more __.

Pink color-solution will disappear by the addition of unsaturated fatty acids

Positive result of Unsaturation Test

Pink color-solution will not disappear

Negative Result of Unsaturation Test

Olive Oil and Lecithin - Positive Coconut Oil and Glycerol - Negative

Unsaturation Test Results for Olive Oil, Coconut Oil, Lecithin, and Glycerol

Acrolein test

is used to detect the presence of glycerol or fat.

dehydrating; potassium bisulfate (KHSO4)

When fat is treated strongly in the presence of a __ agent like __, the glycerol portion of the molecule is dehydrated to form an unsaturated aldehyde, acrolein that has a pungent and/or irritating odor.

unsaturated aldehyde

acrolein that has a pungent and/or irritating odor.

Negative

Acrolein Test result is __ if glycerol is not dehydrated by potassium bisulfate due to insufficient amount or if sample added has no glycerol at all.

All positive

Acrolein Test Result for Olive Oil, Coconut Oil, Lecithin, and Glycerol

Solubility test

is the preliminary test which detects the presence of all lipids.

polar or nonpolar

Solubility test detects the solubility of lipid in various solvents to check whether it is miscible or immiscible in __ solvents.

True

T/F Solubility test is based on the property of lipid to dissolve in different solvents.

non-polar; chloroform

Lipids are readily miscible in __ solvents like _

__

polar; ethanol

Lipids are partially soluble in a __ solvent like __

polar; water

Lipids are immiscible in a __ solvent like __

soluble

Lipids are __ in non-polar solvent i.e. chloroform and partially soluble in ethanol which can solubilize upon heating

insoluble

Lipids are __ in a polar solvent i.e. water.

All are insoluble to water except Glycerol

Solubility Test of Glycerol, Olive Oil, Coconut Oil, and Lecithin to Water

All are soluble to Cyclohexane except Glycerol

Solubility Test of Glycerol, Olive Oil, Coconut Oil, and Lecithin to Cyclohexane

All are insoluble to Acid except Glycerol

Solubility Test of Glycerol, Olive Oil, Coconut Oil, and Lecithin to Acid (HCl)

Glycerol is soluble to Base, while there are reactions that occurred on others

Solubility Test of Glycerol, Olive Oil, Coconut Oil, and Lecithin to Base (NaOH)

cell membrane

Every cell has __ which separates it from outside environment.

lipids; proteins

The cell membrane is consists of double layer of __, embedded with __.

semipermeable

Cell membranes are __, of which only certain substances are allowed to travel in and out of the cell.

amphipathic

Cell membrane's structure creates a barrier between the extracellular environment and the intracellular environment, due to the chemical properties of the phospholipids being __, having both hydrophilic and hydrophobic ends.

one another; outward; selectively permeable

In the phospholipid bilayer, the fatty acid hydrophobic tails will orient themselves to face __ with the hydrophilic phosphate heads facing __ toward the aqueous environments. This structure allows the membrane to be __.

Cell membrane

plays an important role in the transportation of specific substances in and out of the cell.

True

T/F Cell membrane transports important nutrients in the cell and also transports toxins out of the cell. This transportation of different molecules in and out of the cell, follows different pathways depending on the nature of the molecule.

Active, Passive, Facilitated Transport

Types of cell transport

Active Transport

Includes bulk transport that uses vesicles to move relatively large amounts of substances across the membrane and active transport through specialized channels that use the power of ATP.

Passive Transport

Is the simplest method of transport and is dependent upon the concentration gradient or difference in concentration.

osmosis, diffusion and facilitated diffusion

Diffusions included in passive transport

Diffusion

Is the movement of particles from a region of higher concentration to a region of lower concentration (example: diffusion of perfume)

Osmosis

Is the net movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Facilitated Diffusion

Is a form of passive transport mediated by transport proteins embedded within the cellular membrane.

Tonicity

Is the ability of an extracellular solution to make water move into or out of a cell by osmosis.

Hypotonic

A solution has a lower concentration of solutes than are found in the intracellular fluid.

Hypotonic

Less solute outside cell than inside cell. Water rushes into cell

Hypotonic

Cell swells and can burst in this solution

Isotonic

A Solution is one that has the same concentration of solutes that are found in the intracellular fluid.

Isotonic

There is no net movement in this solution. Concentration inside = concentration outside

Hypertonic

A solution has a higher concentration of solutes than are found in the intracellular fluid.

Hypertonic

There is more solute outside cell than inside cell. Water rushes out of the cell

Hypertonic

Cell shrivels/shrinks and can die in this solution

0cm, 3.3cm, 3.8 cm, 4.8 cm, 6.7 cm

Level of water in osmosis from 0 min, 15 min, 30 min, 45 min, 1 hr

Hypotonic

0.1 and 0.5 g of salt mixed with water is a __ solution

Isotonic

1g of salt mixed with water is a __ solution

Hypertonic

1.5 and 2 g of salt mixed with water is a __ solution