Lipids Flashcards
What is a lipid?
A carbon-containing compound found in organisms
Largely nonpolar and hydrophobic
Do lipids dissolve in water?
Lipids do not dissolve easity in water
Lipids are hydrocarbons- What does this mean?
They only contain hydrogen and carbon
Lipids are nonpolar molecules which means their ends are …?
Not charged
Why are lipids not soluble in water?
They are nonpolar and water is polar meaning that they do not share or bond electrons
Fatty acids are the tails of lipids. What is a fatty acid?
Long hydrocarbon chains that end with a carboxyl (-COOH) group
What is the general formula?
H3C-(CH)n-COOH
What do unsaturated fatty acids contain?
One or more double bond
Do unsaturated fatty acids have a high or low melting point?
Low melting point
What state is staurated fatty acids of less than 10 carbons at in room temperature?
Liquid
Are sturated fatty acids are liquid at room temperature?
Yes
What does cis mean?
The hydrogens either side of the double bond may be on the same side
What dies trans mean?
The hydrogens either side of the double bond may be on the opposite side of the double bond
Do the most naturally occuring unsaturated fatty acid contain cis or trans configuration?
Cis
Are trans fats rare?
Yes
How are trans fats made?
From cis-unsaturated fats in an industria; process called hydrogentaion
What bonds are converted in hydrogenation?
Double bonds are converted into single bonds
Cis bonds are conerted into a trans formation
Nucleotides, lipids and carbohydrates are defined by what proterty?
Physical property
What are the three most important types of lipids found in cells?
Steroids, phospholipids and fats
What is an example of a steroid?
Cholesterol
How are steroids distinguished?
Bt the four-ring structure
How do steriods differ?
By functional group or side groups attached to these rings
Why is cholesterol an important component of plasma membranes?
Provides stability in membranes
What are steroids used for?
A starting point for the synthesis of hormones
- Oestrogen
- Progesterone
- Testosterone
What does a phospholipid consist of?
Three carbon molecules called glycerol
Where are phospholipids containing fatty acid chains found?
In the domains bacteria and eukarya
How many fatty acid chains are linked to a single glycerole molecule?
Three
What reaction happens for fatty acids and phospholipids to form?
Condensation reaction
Where does the condensation reaction occur in fats and phospholipids?
Between the hydroxyl group of glycerol and the carbonyl group of fatty acid
How does glycerol and fatty acids become joined?
Ester linkage
Are phospholipids and fats polymers?
No
Are fatty acids monomers?
No
Do membrane lipids have a hydrophobic, polar region?
Yes
Does the tails or head of the membrane lipids react when in water solution?
The heads are polar so they are hydrophilic and interact with water
The tails are non polar so they are hydrophobic and do not interact with water
What is the term for compounds that contain both hydrophilic and hydrophobic elements?
Amphipathis
Do phospholipids dissolve when placed in water?
No
Do the heads or tails react with the water?
Heads
What are the two types of structures that phospholipids spontaniously form when in water?
Micelles and bilayers
What does it mean when a structure forms independently?
There is no energy input required
How are micelles formed?
When hydrophilic heads face the water and hydrophobic tails are forced together away from the water
When are lipid bilayers formed?
When two sheets of lipids align with hydrophilic heads facting the solution and hydrophobic tails facing one another inside the bilayer
Are the tails long or short in micelles?
Short
Are the tails long or short in lipid bilayers?
Long
What happens when the spotaneous formation of lipid bilayers and sealed compartments?
They capture other chemicals within
What are fats based ion?
Fatty acids
How are fatty acids classified?
the chain length and number of double bonds
What does chin length determine?
Melting and boiling points
