Molecules of Life

1
Molecules of Life

• Organic Compounds

2
Major Organic Molecules

• Carbohydrates
• Proteins
• Lipids
• Nucleic Acids

3
Elements In Organic Compounds

• Carbon, which forms the backbone of organic
  molecules
• Hydrogen, oxygen and nitrogen which make up the
  functional groups in organic compounds

4
Carbons Bonding Behavior

• Outer shell of carbon has 4 electrons can hold 8
• Each carbon atom can form covalent bonds with up
  to 4 atoms

Remember in the lab, carbon was a black circle
with 4 prongs. Each prong represents a bond that
carbon can form with another atom.
5
Bonding Arrangements

• Carbon atoms can form chains or rings
• Other atoms project from the carbon backbone

Glucose (ball-and-stick model)
6
Functional Groups

• Atoms or clusters of atoms that are covalently
  bonded to carbon backbone
• Give organic compounds their different properties

7
Examples of Functional Groups
8
Subunits of Organic Molecules

• Carbohydrate subunit is a monosaccharide
• Protein subunit is an amino acid
• Lipid subunits are glycerol and 1,2 or 3 fatty
  acids
• Nucleic acid subunits are nucleotides consisting
  of a sugar, a base and a phosphate group

9
Condensation Reactions or Dehydration Synthesis

• Form polymers from subunits of organic compounds
• Enzymes remove OH from one molecule, H from
  another, form bond between two molecules
• Discarded atoms can join to form water

10
Hydrolysis

• Breaks polymers into smaller units
• Enzymes split molecules into two or more parts
• An OH group and an H atom derived from water are
  attached at exposed sites

11
Carbohydrates

• Elemental relationship is 1 carbon 2 hydrogen 1
  oxygen
• Primary function is to provide energy to an
  organism.
• Energy comes from breaking the C-H bonds
• Common examples are glucose, sucrose and
  cellulose

12
Carbohydrates

• Monosaccharides
• Simple sugars
• Glucose, fructose, ribose
• Oligosaccharides
• Short-chain carbohydrates
• Sucrose
• Polysaccharides
• Complex carbohydrates
• Glycogen, starch, cellulose, chitin

Cellulose fibers in the plant cell wall.
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Carbohydrate Subunit monosaccharide
14
Lipids

• Primary function is to store energy.
• Lipids are a better source of energy than
  carbohydrates because they contain more C-H
  bonds.
• Hydrocarbon determines if saturated or
  unsaturated
• Common examples are fats and waxes
• Phospholipids are important in cell membranes

15
Saturated Fats

• Have no double bonds between the carbon atoms of
  the fatty acid chain
• Hence, they are fully saturated with hydrogen
  atoms.
• Associated with heart disease

16
Unsaturated Fats

• Have one or more double bonds in the fatty acid
• Healthier than saturated fats

17
Lipid Subunits glycerol and fatty acids

• glycerol containing
• hydroxyl groups
• (-OH)

Fatty acid containing a carboxyl group (-COOH)
18
Proteins

• Most diverse in structure and function
• Functions include transport and communication
  between cells, maintenance and repair of tissue,
  enzymes and hormones

19
Protein Subunits Amino Acids

• Carbon covalently bonded to an amino group (NH3
  or NH2), a hydrogen atom, a carboxyl group (COOH)
  and an R or radical group

20 different R groups form 20 different amino
acids
20
Nucleic Acids

• Their primary function is to store and retrieve
  heritable information
• There are two nucleic acids DNA and RNA

21
DNA

• Double-stranded
• Sugar-phosphate backbone
• Covalent bonds in backbone
• H bonds between bases adenine, cytosine, guanine
  and thymine

22
RNA

• Single-stranded
• Sugar phosphate backbone
• Covalent bonds in backbone
• Hydrogen bonds between bases adenine, guanine,
  cytosine and uracil

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• The
• End