CHAPTER 5 THE STRUCTURE

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CHAPTER 5THE STRUCTURE FUNCTION OF
MACROMOLECULES

• CARBOHYDRATES, LIPIDS, PROTEINS, NUCLEIC ACIDS

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Collins I3 lines

• Explain pH

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Objectives

• Macromolecules are polymers
• Sugars (smallest carbohydrate) are used for fuel
  and carbon sources
• Polysaccharides (polymers of sugar) have storage
  and structural roles
• Fats store large amounts of energy
• Phospholipids are a part of the cell membrane
• Steroids cholesterol and hormones
• Proteins' function depends on its shape
• Nucleic Acids store and transmit hereditary info
• RNA and DNA

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Root Words

• Con
• Di
• Glyco
• Hydro
• Macro
• Meros
• Mono
• Poly
• Tri

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MOLECULES TO RECOGNIZE
Basic Protein Structure Cellulose Amino
Acid Structure Glycogen Steroids
Glucose
Phospholipids
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The Synthesis Breakdown of Polymers. Fig. 5.2
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Monosaccharides - Simple Sugars (Fig. 5.3) Note
Asymmetric Carbons in Hexose Sugars
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Carbohydrates - Carbon Hydrated ( 121
ratio ) ( C ) ( H2O )
Sugars - Major role - Energy. Fig. 5.4)
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Disaccharide - Dehydration Synthesis Glycosidic
Linkage. (Fig. 5.5)
Sucrose Glucose Fructose Lactose
Glucose Galactose
1-4 1-2 Linkage
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Starch is in the form of Amylose Amylopectin
(Fig. 5.7) (in PLANTS) GLYCOGEN is also called
animal starch, stored in muscles liver.
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POLYSACCHARIDES -3 OR MORE MONOSACCHARIDES. 1.
Structural a. Cellulose - cell walls of
plants. b. Chitin - exoskeleton of arthropods
(insects spiders etc.) and exterior of
mushrooms 2. Storage - Starch Glycogen
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LIPIDS - Diverse Hydrophobic Molecules (Fig. 5.10)
FATS
Made of 1 glycerol 3 fatty acids (16 to 18
carbons). C-H on fatty acids make lipids
hydrophobic
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Saturated Fatty Acids - have no double bonds
between the carbons in the chain (solids at room
temp)
Unsaturated Fatty Acids - have double bonds
between the carbons in the chain. (Liquids at
room temp due to kinks in the fatty acid which
prevents it from solidifying)
Fat Molecules are storage for energy.
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Second Type of Lipid Phospholipid
Have 2 fatty acids NOT 3 like lipids
Major components of cell membranes. Hydrophilic
head Hydrophobic tail. Kink in one fatty acid
means it has double bonds (Fig. 5.12)
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Phospholipid Bilayer is found in cell membrane.
Fig. 5.13 Outside of cell
Inside of cell
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3rd Type of Lipid - Steroids Lipids with carbon
skeleton of 4 interconnected rings.
Cholesterol - common component of cell membranes.
(Fig. 5.14).
Also precursor for other steroids such as
hormones including sex hormones.
Cholesterol
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Sex Hormones

• What is the male sex hormone?
• What is the female sex hormone?

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Nucleic Acids

• DNA

• RNA

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Proteins

• Storage
• Structural support
• Transport of substances
• Cell to cell signaling
• Movement
• Defense against foreign substances
• Enzymes speed up chemical reactions

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Amino Acids

• Amino acids contain carboxyl and amine
  functional group
• Link together by peptide bonds to form a
  polypeptide chain
• Only 20 amino acids

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Protein Structure

• 4 levels
• Primary Structure precise sequence of amino
  acids
• Secondary Structure coils or folds within the
  sequence due to Hydrogen bonding.
• The H bonds are weak, but can support a
  particular shape
• Alpha (a) helix - coil
• Beta (B) pleated sheet - fold

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Protein Structure Cont.

• Tertiary Structure
• Irregular looping and folding of the protein bc
  of interactions of side groups
• Quaternary Structure
• The addition of one or more polypeptide chains to
  the original structure

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Changes in Protein

• Denature when a protein unravels due to changes
  in pH, salt concentration, temperature and
  environment