Biomolecules – Part 3Lipids and Nucleic Acids

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Lipids

I. Main Function in Cell: A. Long term energy storage

B. Part of cell membrane (phospholipids)

C. Chemical messengers (hormones)

D. Insulation and protection

II. Main Dietary Sources:

A. Vegetable and canola oils

B. Fatty meats like beef and pork

C. Milk, butter and cheese

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Lipids

I. Common Elements:

A. Carbon, Hydrogen and Oxygen

II. Building Block - Triglycerides: composed of 1 glycerol and 3 fatty acids.

H

H-C----O

H-C----O

H-C----O

H

glycerol

O

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

=

fatty acids

O

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

=

O

C-CH2-CH2-CH2-CH=CH-CH2-CH

2-CH2-CH

2-CH3

=

3

Lipids

I. Saturated fatty acids:

A. Found in dairy and meats

B. No double bonds (bad)

C. Saturated with hydrogen

D. Solid at room temperature

E. Examples: butter, lard, CriscoO

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

=

saturated

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Lipids

I. Unsaturated fatty acids:

A. Found in vegetable oils (plant fats)

B. Double bonds (good)

C. Less hydrogen than saturated fats

D. Liquid at room temperature

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Lipids

I. Sterols:

A. Carbon with 4 fused rings

B. Example: Cholesterol – important steroid in the membrane of animal cells; excessive amount are high risk for a heart disease.

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Lipids

I. Phospholipids:

A. Have only 2 fatty acid chains instead of 3

B. Make up a majority of cell membrane structure

http://micro.magnet.fsu.edu/cells/plasmamembrane/images/plasmamembranefigure1.jpg

a. Hydrophobic – Does NOT like water - “Tail”

b. Hydrophilic – Likes water – “Head”

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Nucleic Acids

I. Main function in cell:

A. Heredity

B. Transmit information on how to make proteins

II. Main dietary sources:

A. Vegetables like beans, peas and spinach

B. Meats and seafood

C. Liver

III. Two types of nucleic acids (polymers):

A. deoxyribonucleic acid (DNA-double helix)

B. ribonucleic acid (RNA-single strand)8

Nucleic Acids

I. Common elements:

A. Made of: carbon, hydrogen, oxygen, nitrogen, phosphorous (CHONP)

II. Monomer

A. Nucleotides

1. phosphate group

2. sugar (5-carbon)

3. nitrogenous bases

a. Pyrimidine – 1 ring (cytosine (C), thymine (T), uracil (U))

b. Purine – 2 rings (adenine (A), guanine (G))

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Nucleotide

OO=P-O O

Phosphate Group

NNitrogenous base (A, G, C, or T)

CH2

O

C1C4

C3 C2

5

Sugar(deoxyribose)

Nucleic acids

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DNA - double helix

P

P

P

O

O

O

1

23

4

5

5

3

3

5

P

P

PO

O

O

1

2 3

4

5

5

3

5

3

G C

T A

i. Two strands of DNA join together through hydrogen bonding to form a double helix.

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