Ch22
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Transcript of Ch22
Molecules of Life
Chapter 22
Great Idea:A cell’s major parts are constructed from a few simple molecular building
blocks
Chapter Outline
• Organic Molecules• Proteins: The Workhorses of Life
• Carbohydrates• Lipids• Minerals and Vitamins
Organic Molecules
Four Basic Characteristics
• Most molecules based on chemistry of carbon– Organic molecules
• Life’s molecules form from few elements– H, O, C, N 97.5% of body weight
Four Basic Characteristics –cont.
• Molecules composed of simple building blocks– Arranged differently
• Shape determines behavior– Determines ability for bonding
Atoms in the Human Body
• No H atoms or bonds to H are shown
• C atoms are not shown explicitly
Chemical Shorthand
Shorthand
Science in the Making
• The synthesis of urea– Friedrich Wohler
Proteins: The Workhorses of Life
Amino Acids: Building Blocks of Proteins
• Amino acid– Carboxyl group– Amino group– Carbon atom– Side group
• Side group– Makes amino acid unique
Amino Acid Structure
Distinctive Side Chain on Amino Acids
Amino Acids - cont.
• Bonding– Two amino acids
•H bonds with OH
•Forms H2O
•Forms peptide bond
– Polypeptide• Chain
Proteins
• Protein– Large molecule– Chain of amino acids
• Only 20 amino acids in living organisms
Structural Proteins
The Structure of Proteins
• Primary structure– Linear sequence of amino acids
• Secondary structure– Bending due to hydrogen bonds
• Tertiary structure– Disulfide bridges and other bonds
• Quaternary structure– More than one polypeptide chain
The Structure of Proteins
Science by the Numbers
• How many proteins can you make?
Proteins as Enzymes
• Enzymes– Specific shape and structure– Facilitates bonding– Recycled
An Enzyme in Action
Computer-Generated Image of an Enzyme in Action
The Science of Life
• Proteins and diet– Essential amino acids– High-quality proteins– Low-quality proteins
Essential Amino Acids in Eggs and Cornmeal
Balanced Protein Meal
How Drugs Work
• Blocking enzymes– Block active site– Molecules cannot bond– Reaction does not take place
• Shape of molecules– Block membrane transport– Block neurotransmitters
Carbohydrates
Carbohydrates
• Structure– C, H, O
• Simplest - sugars – CnH2nOn
• Monosaccharides• Polysaccharides
– Starches– Cellulose
Glucose
Fructose
Polysaccharides
Lipids
Lipids
• Lipids– Insoluble in water
• Role of lipids– Cell membranes– Store energy
• Phospholipids– Make up cell membrane
Lipids and Water Are Immiscible
Structure of a Phospholipid
Saturated and Unsaturated Fats
• Saturated– Carbon is fully bonded– Basis of cholesterol
• Unsaturated– Monounsaturated– Polyunsaturated
•Hydrogenation
Saturated vs. UnsaturatedLipids
Technology
• Nonfattening fats
Cell Membranes
• Cell membrane– Hydrophilic– Hydrophobic
Lipid Bilayer
Minerals and Vitamins
Vitamin and Mineral Supplements
Minerals
• Minerals– All chemical elements except C, H, N, O
• Example– Calcium
•2% of weight
RDAs for Minerals
Vitamins
• Vitamins– Organic molecules– Must be taken in with food
•Except vitamin D
• Function– Assist enzymes
Types of Vitamins
• Water soluble– Vitamins B & C
• Fat soluble– Vitamins A, D, E, & K
Citrus Fruit and Vitamin C
RDAs for Vitamins