1. Chapter 2: The Molecules of Cells
Unit 1: Cell Biology
Chapter 2: The Molecules of Cells

2. Covalent Reactions Atoms SHARE electrons

3. More Covalent Reactions

4. Ionic Reactions Atoms GAIN or LOSE electrons Ionic bond= attraction between oppositely charged ions

5. Hydrogen Bonds
Hydrogen bond = covalently bonded hydrogen is positive and attracted to a negatively charged atom
Polarity of H20
Hydrogen bonds
Cohesive

6. pH Scale Acidic: pH <7 [H+] > [OH-] Neutral: pH = 7 [H+] = [OH-]
Note to self:
[H+] = hydrogen ions
[OH-]= hyrdoxide ions
Acidic: pH <7
[H+] > [OH-]
Neutral: pH = 7
[H+] = [OH-]
Basic: pH >7
[H+] < [OH-]

7. Synthesis (dehydration) & Hydrolysis
Monomer= simple organic molecule, exists individually
Polymer/Macromolecule= many monomers linked together

8. Examples of Monomers and Polymers
carbohydrate
monosaccharide
protein
Amino acids
Nucleic acid
nucleotides
lipids
Fatty acids
See page 31 in Inquiry into Life text

9. Carbohydrates (CH2O)n Functions: a) quick & short term energy storage
b) structural role in plants, bacteria, insects
Types:
Monosaccharide= simple sugar, 3-7 carbon atoms
ex. Glucose, fructose, galactose
Disaccharide= two monosaccharides joined by dehydration ex. Maltose, sucrose, lactose
Polysaccharide= long polymers of many glucose subunits
ex. Starch, glycogen, cellulose

10. Synthesis and Degradation of Maltose, a disaccharide

11. Lipids Functions: energy storage Types: Fats (triglyceride) and Oils
Saturated Fatty Acid= no double covalent bonds between carbon atoms (saturated)
Unsaturated Fatty Acid= has double bonds between carbon atoms
Phospholipids- like fats but has phosphate group instead of third fatty acid
Steroids- has a backbone of 4 fused carbon rings (Cholesterol is a type of steroid)

12. Synthesis and Degradation of a Fat molecule

13. Structure of a phospholipid and steroid
See Figures 2.22 and 2.23 in Inquiry into Life textbook

14. Proteins Proteins= polymers of amino acid monomers
Many functions! Some examples:
Keratin- skin and nails
Collagen- ligaments, tendons, skin
Many hormones
Actin and Myosin- allow muscles to contract
Hemoglobin- transport oxygen in blood
Antibodies in the blood
Allow movement through cell membrane
Enzymes (speed up chemical reactions)

15. Representative Amino Acids

16. Synthesis and Degradation of a dipeptide
Amino acids Polypeptides Proteins

17. Levels of Protein Organization
Primary: linear sequence of amino acids joined by a peptide bond
Secondary: polypeptides take on a certain orientation in space (alpha helix or pleated sheet) due to hydrogen bonding between peptides
Tertiary: final 3D shape maintained by various bonding (covalent, ionic and hydrogen)
Quaternary: only in some protein, due to polypeptide arrangements

18. Levels of Protein Organization

19. Nucleic Acids Two Types: DNA RNA Sugar Deoxyribose Ribose Bases
A,G,T,C
A,G,U,C
Strands
Double
Single
Helix
Yes No
Functions
Genetic material that specifies protein synthesis
mRNA, rRNA, or tRNA
Function in protein synthesis

20. Overview of DNA structure

21. ATP (Adenosine Triphosphate)
Energy carrier in cells
High energy molecule because last two phosphate bonds are unstable and easily broken