General Sturcture

1
Chapter 2
Part II
2
Proteins

• General Sturcture
• Amino Acids
• Functional groups
• Amine Group
• Organic Acid Group
• Peptide bonds
• Macromolecules

3
Proteins

• Structural Levels
• Primary
• Simple linear chain
• Secondary
• Alpha helix
• Beta pleated sheet

4
Proteins

• Structural Levels
• Tertiary
• Alpha helix or beta pleated regions fold upon
  one another
• Forms globular molecule
• Maintained by both covalent an hydrogen bonds.
• Quaternary
• 2 or more polypeptide chains aggregate in a
  regular manner to form complex protein.

5
Proteins

• Appearance and shape (Table 2.3 PG 52)
• Fibrous proteins
• Secondary or quaternary
• Extended and strandlike
• Examples
• Collagen
• Keratin
• Elastin
• Contractile proteins

6
Proteins

• Appearance and shape
• Globular proteins
• Compact, spherical
• Most are tertiary
• Few are quaternary
• Examples
• Antibodies
• Hormones
• Enzymes

7
Proteins

• Protein Denaturation
• Activity of protein depends on 3-dimensional
  structure
• Hydrogen bonds are important in maintaining
  structure
• Hydrogen bonds are fragile. Broken by
• Excessive acidity
• Heat

8
Proteins

• Protein Denaturation
• Some disruption in structure is reversible.
• Denatured globular proteins can no longer perform
  their roles.
• Arrangement of atoms is important
• Active sites

9
Proteins

• Chaperonins
• Found in all cells
• Unrelated globular proteins
• Help proteins achieve their functional
  3-dimensional structure
• Numerous protein-related roles
• Prevent accidental, premature, or incorrect
  folding
• Promote breakdown of damaged proteins
• Help translocate proteins and certain metal ions
  across cell membrane

10
Proteins

• Chaperonins
• Found in all cells
• Unrelated globular proteins
• Help proteins achieve their functional
  3-dimensional structure
• Numerous protein-related roles
• Aid in besired folding and association process
• Vitally important to cell function in all types
  of stressful circumstances.

11
Proteins

• Enzymes
• Globular
• Biological catalysts
• Types
• Pure proteins
• Holoenzyme
• Apoenzyme
• Cofactor

12
Proteins

• Enzymes
• Mechanism of enzyme action
• Enzymes active site must first bind with a
  substrate
• Enzyme-substrate complex undergoes internal
  rearrangements that form the product
• Enzyme releases the product of the reaction.

13
Nucleic Acids

• Nucleotides
• Nitrogen base
• Purine
• Pyrimidine
• Pentose sugar
• Deoxyribose
• Ribose
• Phosphate group

14
Nucleic Acids

• Classes
• DNA
• Found in nucleus
• Long double-stranded polymer
• 4 nitrogen bases
• Deoxyribose sugar
• Two halves are held together by hydrogen bonds

15
Nucleic Acids

• Classes
• RNA
• Located outside nucleus
• Single strand
• Three types
• 4 nitrogen bases
• Ribose sugar

16
Adenosine Triphosphate

• ATP
• Energy molecule
• Adenine containing RNA molecule with two
  additional phosphate groups