This has been the 1337th visit to this site since Sept. 5, 1996.

OUTLINE:

LIPIDS

FATS

SATURATED

UNSATURATED

PHOSPHOLIPIDS

STEROIDS

CHOLESTEROL

PROTEINS

AMINO ACIDS

NONPOLAR

POLAR

A. LIPIDS = INSOLUBLE IN H2O

3 TYPES:

1. FATS

2. PHOSPHOLIPIDS

3. STEROIDS

...

1. FATS

Constructed of:

GLYCEROL = a 3 Carbon alcohol

and a

FATTY ACID = CARBOXYL Grp. on a HYDROCARBON

"TAIL" (w/ 16-18 Cs)

hooked via an

ESTER LINKAGE (up to 3 per glycerol)

(or an ETHER linkage in the Archaebacteria)

(Fig. 5.10)

SATURATED FATS = saturated w/ Hs

= no double bonds between Cs

= Solid at room temp.

= Most animal fats (e.g. lard, butter)

..

..

= Some double bonds between Cs

= Liquid at room temp.

= Most plant fats (olive oil)

(Fig. 5.11)

...

1. Energy storage twice as much energy per C and more compact than starch

2. Cushions vital organs in mammals

3. Insulation (e.g. whales and seals)

..

PHOSPHOLIPIDS = GLYCEROL + 2 F.A.s + PHOSPHATE Grp.

Phosphate group may have another group attached to it.

polar "head" and non-polar "tail"

(Fig. 5.12)

important in membranes = phospholipid BILAYER

(Fig. 5.13)

STEROIDS = Have 4 fused C RINGS w/ diff. Functional groups

..

CHOLESTEROL

(Fig. 5.14)

Precursor of hormones and bile acids

In Membranes

Too Much = atherosclerosis

..

PROTEINS

FUNCTION: MANY (see Table 5.1)

1. ENZYMES catalysts of cellular rxns.

2. Movement (contractile proteins)

3. Receptor Proteins on Cell Surface

4. Transport (e.g. Hemoglobin)

5. ANTIBODIES

6. Structural (Collagen etc.)

etc. etc. more in Table 5.1.

..

AMINO ACIDS = Building blocks of proteins (monomers)

20 in living organisms

..

..

STRUCTURE:

asymmetric C hooked to:

1. AMINO Grp.

2. CARBOXYL Grp.

3. H

4. R group (= side chain that is diff. for each Amino Acid)

20 COMMON Amino Acids:

(Fig. 5.15)

Grouped by properties of R group:

NONPOLAR R group

POLAR R group

a. uncharged

b. charged

acidic

basic

..

POLYPEPTIDE CHAINS

PEPTIDE BOND = Covalent Bond formed via a condensation rxn. between amino acids

(Fig. 5.16)

.. POLYPEPTIDE CHAIN

backbone = C-C-N-C-C-N-C-C-N-C-C-N

C-terminus

N-terminus

.. PROTEIN CONFORMATION = 3-D SHAPE

Consequence of sequence of a.a.s

Native Conformation = Conf. in cell

function depends on conformation