1. Molecular Interactions2

2. About this Chapter Atoms, ions, and molecules (self review)
Types of chemical bonds (self review)
Biomolecules
Solutions, concentrations, and pH
Water Properties
Protein interactions

4. Types of Biomolecules
All four types are composed of either monomers or covalently linked polymers. The first three provide energy to the body.
Monomers are connected by dehydration reactions to create polymers
Polymers are broken down into monomers by hydrolysis reactions
The four groups of biomolecules (organic macromolecules) are:
Carbohydrates
Lipids
Proteins
Nucleotides and nucleic acids

5. Most macromolecules are polymers
Polymers are made by stringing together many smaller molecules called monomers
Cells link monomers by a process called dehydration synthesis
In this process water is removed to unite the two units and form a polymer.
Short polymer
Monomer
Longer polymer
Figure 3.7A
(a) Dehydration synthesis of a polymer

6. Polymers broken to monomers
Organisms also have to break down macromolecules
Cells do this by a process called hydrolysis
In hydrolysis a water molecule is used to split a bond between two monomers to reduce the size of the polymer.
Figure 3.7B
(b) Hydrolysis of a polymer

7. Carbohydrates Most abundant Simple Complex Carbon Hydrogen Oxygen
Monosaccharides (glucose, ribose)
Complex
Polysaccharides (glycogen, starch)
Monomer linked to form polymers by a glycosilic bond

8. Carbohydrates
Figure 2-7 (1 of 3)

9. Carbohydrates
Figure 2-7 (3 of 3)

10. Fun Facts
Americans consume an average of 140 pounds of sugar per person per year
Cellulose, found in plant cell walls, is the most abundant organic compound on Earth

11. Lipids Carbon and hydrogen (little oxygen) Structurally diverse
Eicosanoids
Steroids
Phospholipids
Triglycerides
Glycerol
Fatty acid chains
Saturated
Unsaturated

12. High Energy Fuel Source
Larger hydrocarbons
Are the main molecules in the gasoline we burn in our cars
The hydrocarbons of fat molecules provide energy for our bodies
Figure 3.4

13. Lipids and Lipid-Related Molecules
Figure 2-8 (1 of 5)

14. Proteins Amino acids Protein structure Most versatile Essential
Amino group
Acid group
Protein structure
Polypeptides
Primary through quaternary
Most versatile

15. The four types of proteins
(b) Storage proteins
(d) Transport proteins
(a) Structural proteins
(c) Contractile proteins
Figure 3.18

16. Levels of Organization in Protein Molecules
Figure 2-9 (1 of 6)

17. Protein Shape Proteins have four levels of structure Hydrogen bond
Pleated sheet
Polypeptide
(single subunit)
Amino acid
(a) Primary structure
Complete
protein,
with four
polypeptide
subunits
Hydrogen bond
Alpha helix
(b) Secondary structure
(c) Tertiary structure
(d) Quaternary structure
Figure 3.23

18. Proteins
Various types of bonds interact to create different types of proteins. The types of bonds that shape the protein affect the structure.
Fibrous
Globular
Figure 2-10

19. Nucleic Acids Composition Base, sugar, and phosphate(s)
Transmit and store
Information (genetic code)
Energy transfer molecules
ATP, cAMP,
NAD, and FAD

20. Nucleotides, DNA, and RNA

21. Aqueous Solutions Aqueous Solution Solubility Water-based
Solute dissolves in solvent
Solubility
Ease of dissolving
Hydrophobic
Hydrophilic

22. Aqueous Solubility
Sodium chloride dissolves in water
Figure 2-14

23. Water properties Molecular structure
Hydrogen bond-the high amount of hydrogen bond in water give it properties no found in other substances. It makes it less dense as a solid and give a high specific heat.
Surface tension- results from cohesion and adhesion
Cohesion- water molecules stick together
Adhesion-water molecules stick to surfaces
Biological Process
Water can absorb and store large amounts of heat while only changing a few degrees in temperature thus allowing it to regulate heat in the body.

24. Water properties
These illustrate the properties of water that result from hydrogen bonding.

25. Hydrogen Ion Concentration (pH)-self review
Acid
Contributes H+ to solution
Base
Decreases H+ in solution pH
- log [H+]
Buffer minimizes changes of pH

26. Hydrogen Ion Concentration (pH)
pH scale
Mechanisms in the body closely regulate blood ph to protect from the harmful effects of going beyond the range.
Figure 2-15

27. Protein Interactions
Human Proteomics Initiative- determine all the types of proteins in the body.
Protein Solubility- the degree to how water soluble a protein is determines influences is role in the body
Insoluble – create supportive structures like collagen and keratin
Soluble- carry out chemical reactions and interact with molecules
Seven categories- these include enzymes, membrane transporters, signal molecules, receptors, binding and regulatory proteins, and antibodies.

28. Protein Interactions
Binding- when proteins binds a conformation change called induce fit occurs. The bind success depends on:
Selectivity- protiens bind specific molecules
Ligand- generic name for molecules that bind and interact
Substrate- ligands that bind enzymes and membrane transporter
Binding site- area where ligand attaches and forms reversible or irreversible bonds
Specificity- the ability of a protein to bind a certainligand
Affinity- degree to which a protein is attracted to a ligand. A high disassociation constant indicates low affinity.

29. Selective Binding: Induced-Fit Model
The induced-fit model of protein-ligand binding
Figure 2-16

30. Factors that affect protein binding
Isoforms- proteins with similar function but different affinities for the same ligand. Ex- fetal vs adult hemoglobin
Activation – some inactive proteins undergo a physical alteration to become active- like protein hormones and enzymes
Cofactors – must bind to protein to enhance affinity to ligand, usually it’s a functional group or ion.
Lysis – cleaving a protein section to activate it.
Modulators – influences binding or activity of a protein
Chemical modulators – bind covalently or non-covalently to alter binding or activity by decreasing or increasing it.
Antagonists – decreases activity by blocking binding site
Competitive inhibitors – reversible antagonists that competitively bind and can be displaced
Allosteric modulators -reversible antagonists that competitively bind but can not be displaced
Covalent modulators - bind and alter properties to activate or inactivate- ex. penicillin

31. Modulators Alter Binding or Activity

32. Factors that Affect Affinity
Figure 2-18

33. Competitive Inhibition
Figure 2-19

34. Allosteric Modulation
Figure 2-20a

35. Allosteric Modulation
Figure 2-20b

36. Physical Regulators
Temperature- each protein has a adequate temperature for it’s function. Outside of the range it may be denatured of inactivated.
pH- each protein has a adequate temperature for it’s function. Outside of the range it may be denatured of inactivated.
Concentration of protein –amounts in body vary over time to control physiological processes
Up-regulation – programmed production of protein
Down regulation – programmed removal of protein
Concentration of ligand – determines the magnitude of the reponse if the protein concentration is the same.
Reaction rates – speed up as ligand concentration increases up until saturation is reached.

37. Summary Atoms in review Four types of chemical bonds
Four kinds of biomolecules
Aqueous solutions and pH
Proteins in focus