Week 5- carbohydrates and lipids

Lipids function

signalling, energy storage, structure

does the presence of double bonds increase or decrease the melting point of fatty acids?

decrease- it prevents the tight packing of molecules in the way cis/trans structure bends them

Fatty Acid properties

• Are carboxylic acids with long C chains 12-20 C atoms

• Contain C-C bonds or C-H bonds

• fewer functional groups

• hydrolysable lipids are derived from these

How to determine omega 3, 6 or 9 fatty acid?

whichever carbon (from CH3 end start counting) has the double bond

Is this an Omega 3, 6, or 9 fatty acid?

Omega 3

Is this an Omega 3, 6, or 9 fatty acid?

Omega 6

Properties of Waxes

• simplest hydrolysable lipids

• can undergo hydrolysis in presence of acid or base

• esters formed from fatty acid and alcohol

• hydrophobic due to non-polar chains

which has this property?

• can undergo hydrolysis in the presence of acid or base

waxes

Properties of Triacylgycerols’s

• triesters from glycerol and three fatty acids

• are simple or mixed

What makes a triacylglycerol simple or mixed?

• Simple = saturated (do double bonds)

• mixed = means one of the fatty acid chains may be saturated

Properties of Soaps

• Metal salts of fatty acids

• Produced by hydrolysis of triacylglycerols in the presence of a base

• They have hydrophobic and hydrophilic regions

• This allows them to form micelles in water which can carry particles of oils and dirt

2 common types of phospholipids

• Phosphoacylglycerols

• Sphingomyelins

Properties of phosphoacylglycerols

• Most common phospholipid

• Phosphodiester bond to alcohol, this end is charged - Polar head

• non polar tails

2 types:

– Cephalin: Contains ethanolamine or serine.

– Lecithin: Contains choline.

Properties of Sphingomyelins

• Second major class of phospholipids

– They DO NOT contain a glycerol backbone

• They contain a sphingosine instead

– They DO NOT contain an ester

– They only contain one fatty acid

Function of sphingomylins

axon sheaths in the nervous system

function of phosphoacylglycerols

major constituents of cell membranes

Steroid

An organic compound a carbon skeleton with four fused rings arranged in a specific configuration.

Phospholipid

• Lipids containing a phosphorus atom.

• Polar head and nonpolar tail making them amphipathic.

Lipids

A broad group of naturally occurring organic compounds that are generally insoluble in water but soluble in organic solvents.

Biological functions of cholesterol

Cholesterol is a steroid

• Adds rigidity to the cell membrane

• Elevated cholesterol in the bloodstream is in indicator for increased risk of coronary artery disease (heart disease)

• transported in the blood by LDLs and HDLs

Biological functions of Adreno-cortical

• regulate electrolytes in kidney (adrenal-means renal)

What are the four fat soluble vitamins?

• vitamin A, D, E, K

Vitamin A

• fat soluble vitamin

• vision, immune, bone health, hair growth

• non-polar

Vitamin D

• fat-soluble vitamin

• Can be synthesized from UV light

• very little polarity

Vitamin E

• fat-soluble vitamin

• antioxidant

• non-polar

Vitamin K

• fat-soluble vitamin

• essential for blood clotting

• given to newborns to prevent bleeding disorders

• non polar

Which vitamins are non-polar

A, E, K

Biological function of steroids

• Components of cell membranes that alter membrane fluidity

• Signaling molecules.

How are fat-soluble vitamins obtained?

With the exception of Vitamin D which can be synthesized from cholesterol, cells cannot synthesize these compounds and must be obtained in the diet.

Carbohydrates

• Biomolecules made from monosaccharides (sugars).

• Largest groups of organic molecules in nature.

• Tree trunks, leaves, vegetables, fruits, honey, milk, alcohol

Functions of carbohydrates

• fingerprint of cells

• backbone of other molecules

How are carbohydrates represented?

By size:

• Monosaccharides-one

• Disaccharides-two

• Polysaccharides-many

Structural features of monosaccharides

Location of carbonyl group (Aldose vs Ketose)

• C1: aldehyde (monosaccharide is called aldose)

• C2: ketone (monosaccharide is called ketose)

Why are monosaccharides easily dissolved in water?

• highly polar

• many hydroxyl groups form hydrogen bonds with water

Anabolism

Synthesis of larger molecule from smaller subunits

Catabolism

: Break down of a larger molecule into smaller subunits

How are carbohydrates built up and broken down?

• Dehydration- build up

• Hydrolysis- break down

How are disaccharides linked together?

glycosidic linkage / glycosidic bond / glycoside.

What monosaccharides make maltose?

glucose + glucose

What monosaccharides make sucrose?

glucose + fructose

What monosaccharides make lactose?

glucose + galactose

A and B glycosidic linkages

In an alpha (α) glycosidic linkage the bond goes down from the C1; in a beta (β) glycosidic linkage the bond goes up from the C1.

Cellulose

• type of polysaccharide

source: plant

Subunit: B-glucose

Bonds: 1,4

Branches: none

Shape: straight sheets, parallel chains

Starch

• type of polysaccharide

• amylose, amylopectin

• source: plant

  Subunit: A-glucose both

  Bonds: 1,4 amylose 1,6 amylopectin

  Branches: none for amylose, branched for amylopectin

  Shape: straight or branched

Glycogen

• type of polysaccharide

• in animals liver and muscles

• highly branched

• α-1,4 glycosidic linkages & α-1,6 glycosidic linkages

source: animal

Subunit: a-glucose

Bonds: 1,4 1,6

Branches: yes

Shape: super branched, largest

A lipid

Which compound is the following?

A fatty acid

Which compound is the following?

a Wax

Which compound is the following?

a Triacylglycerol

Which compound is the following?

a Soap

Which compound is the following?

Which compound is the following?

a Steroid

Which compound is the following?

a Vitamin

Which compound is the following?

Which compound is the following?

a monosaccharide/carbohydrate

Which compound is the following?

a Dissacharide/carbohydrate

Which compound is the following?

a Polysaccharide/carbohydrate

Which compound is the following?

a monosaccharide

Which compound is the following?