Today:

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Today

• are you using the text materials?
• in-class assignment

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Last time Carbohydrates 1) Simple -
monosaccharides (glucose, fructose) -
disaccharides (maltose, sucrose,
lactose) 2) Complex -
polysaccharides (long chains) (polymers of
monosaccharides) Starch (energy) Glycogen
(storage) Cellulose (structural, energy)
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What are sugar alcohols?

• part of structure resembles a
• sugar molecule and part resembles
• what is found in an alcohol molecule
• converted by body to glucose slowly
• provide fewer calories but they are carbs!
• pros and cons?

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Artificial Carbs

• aspertame
• sucralose
• saccharin

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• Mono and disaccharides dissolve readily in
• water.

• They are hydrophilic, or water-loving

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Lipids

• Lipids are hydrophobic

They do not mix with water

• Fats
• Steroids

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Fats

• Dietary fat consists largely of the molecule
  triglyceride

• A combination of glycerol and three fatty acids

-long hydrocarbon tails -energy stored (long term)
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• Fats perform essential functions in the human body

• Energy storage
• Cushioning of internal organs
• Insulation

Remember 1 fat molecule triglyceride
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• Unsaturated vs. saturated fatty acids

• Unsaturated

• Have less than the maximum number of hydrogens
  bonded to the carbons
• Have double bonds
• Tend to be liquid at room temp.

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Unsaturated vs. saturated fatty acids

• Saturated
• Have the maximum number of hydrogens bonded to
  the carbons
• Tend to be solids at room temp.

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An unsaturated fat molecule
Saturated fatty acid (heart disease)
hydrogenation
Unsaturated fatty acid
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• Most animal fats have a high proportion of
  saturated fatty acids

• Example butter
• Most plant oils tend to be low in saturated fatty
  acids
• Example corn oil

What about peanut butter or cookies made with
vegetable oil?
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Steroids

• Steroids are also a lipid but very different from
  fats in structure and function

• The carbon skeleton is bent to form four fused
  rings
• Cholesterol is the base steroid from which your
  body produces other steroids

Cholesterol
Testosterone
A type of estrogen
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• Synthetic anabolic steroids are controversial

• They are variants of testosterone
• Some athletes use them to build up their muscles
  quickly
• They can pose serious health risks

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Risks of Steroids

• Serious mental and physical problems
• Violent mood swings
• Deep depression
• Liver damage
• High cholesterol
• Reduced sex drive
• Infertility

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Proteins

• A protein is a polymer constructed from amino
  acid monomers (remember building blocks!)

• Proteins perform most of the tasks the body needs
  to function
• They are the most elaborate biological molecule

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• Proteins have a variety of functions

Structural proteins provide support
hair
feathers
Connective tissue
Horns
Spider webs
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Storage proteins provide source of amino acids
for developing plants and animals
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Contractile proteins
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Transport proteins
Hemoglobin iron containing protein
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More types of proteins

• Defensive proteins antibodies
• Signal proteins cell to cell messaging
• Enzymes change the rate of a chemical reaction

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The Monomers Amino Acids

• All proteins are constructed from a common set of
  20 different of amino acids

Arginine
Leucine
Valine
Cysteine
Alanine
Serine
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• Each amino acid consists of

Amino group
Carboxyl group

• A central carbon atom bonded to four covalent
  partners
• A side group that is variable among all 20

Side group
(a)
Side groups
Serine
Leucine
(b)
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Proteins are Polymers of Amino Acids

• The bond between amino acids is called a peptide
  bond
• Polypeptide chain of linked amino acids

Side group
Side group
Amino acid 1
Amino acid 2
Dehydration synthesis
Side group
Side group
Peptide bond
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Proteins 1) vary in the of amino acids they
contain 2) vary in the order of amino acids

• This variation in and arrangement of amino
  acids makes each one different

• Your body has tens of thousands of different
  kinds of protein!

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Protein Shape

• Primary structure

• The specific sequence of amino acids in a protein

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• A slight change in the primary structure of a
  protein affects its ability to function

• The substitution of one amino acid for another in
  hemoglobin causes sickle-cell disease

(a) Normal red blood cell
Normal hemoglobin
(b) Sickled red blood cell
Sickle-cell hemoglobin
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Protein Shape

• Proteins have four levels of structure

Pleated sheet
(a) Primary structure
Alpha helix
(c) Tertiary structure
(b) Secondary structure
(d) Quaternary structure
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What Determines Protein Structure?

• A proteins shape is sensitive to the surrounding
  environment

• Unfavorable temperature and pH changes can cause
  a protein to unravel and lose its shape
• This is called denaturation

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Nucleic Acids

• Storage molecules that have the directions for
  building proteins
• Nucleic because they are found in nuclei of
  eukaryotic cells
• Two types DNA and RNA
• Parts of the DNA program the Amino Acid sequence
  (AA AA AA protein)

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• Nucleic acids are polymers of monomers called
  nucleotides
• Each nucleotide is an organic molecule with three
  parts

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• Nucleotide Nucleotide Nucleotide
  Polynucleotide (DNA strands)

Covalent bond between sugar of one and phosphate
of another sugar-phosphate backbone of DNA
or RNA
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• Read hand out and answer questions and turn in
  answer sheet.
• For Thursday Read Chapter 4