1. The Molecules of Cells
Chapter Three

2. Classes of Compounds Organic compounds Inorganic compounds
Carbohydrates, fats, proteins, nucleic acids
Contain carbon, usually large, covalently bonded
Inorganic compounds
Water, salts, and many acids and bases
Do not contain carbon
Life’s molecular diversity is based on the properties of carbon

3. Characteristic chemical groups help determine the properties of organic compounds
Functional Groups: affect a molecules function by participating in chemical reactions in a characteristic way

4. Cells make a huge number of large molecules from a small set of small molecules
Most Macromolecules are Polymers
Polymers: Large molecules consisting of many similar/identical building blocks linked by covalent bonds
Monomers: Building blocks of polymers
There are four classes of Biological Macromolecules (three are polymers):
Carbohydrates
Proteins
Nucleic Acids
Lipids (not polymers)

5. Polymers Around Us

6. Cells Make and Break Polymers Using Two Main Types of Chemical Reactions
Dehydration (synthesis) reactions: Monomers are linked together to form polymers and a molecule of water is lost
Each monomer contributes part of the H2O molecule that is lost

7. Cells Make and Break Polymers Using Two Main Types of Chemical Reactions
Hydrolysis reactions: Polymers are broken down into monomers by the addition of water molecules
reverse of the dehydration synthesis reactions

9. Carbohydrates Functions Major source of cellular fuel (glucose)
Sugars and starches; polymers of monosaccharides
Contain C, H, and O [(CH20)n]
Three classes
Monosaccharides -Simple sugars containing three to seven C atoms
Disaccharides -Double sugars/too large to pass through cell membranes
Polysaccharides -Polymers of simple sugars, e.g., starch, glycogen, cellulose
Functions
Major source of cellular fuel (glucose)
Structural molecules (ribose sugar in RNA)

10. (a) Monosaccharides
Monomers of carbohydrates
Example
Hexose sugars
Example
Pentose sugars
Glucose
Fructose
Galactose
Deoxyribose
Ribose

11. (b) Disaccharides
Consist of two linked monosaccharides
Example
Sucrose, maltose, and lactose
Glucose
Fructose
Glucose
Glucose
Galactose
Glucose
Sucrose
Maltose
Lactose

13. Lipids Insoluble in water (hydrophobic) Contain C, H, O, sometimes P
Several Classes of Lipids:
Triglycerides
Phospholipids
Steroids

14. Triglycerides Triglycerides—solid fats and liquid oils
Composed of three fatty acids and one glycerol molecule
Main functions of TGs
Energy storage
Insulation
Protection

15. Phospholipids
Composed of two fatty acids, one glycerol and one phosphate group
“Head” and “tail” regions have different properties
Polar head, non-polar tail
Main component of cellular membranes

16. Steroids Lipids composed of fused carbon ring structures
Cholesterol, vitamin D, steroid hormones, and bile salts

17. Proteins Polymers of amino acids Contain C, H, O, N, sometimes S
All 20 amino acids have same basic structure
Amino acids are held together by special covalent bonds called peptide bonds

18. Denaturing Natural Folding PRIMARY SECONDARY TERTIARY QUATERNARY
(protein folding animation 2m 19 s) start around 1:11
QUATERNARY

19. Nucleic Acids Polymers of nucleotides Contain C, O, H, N, and P
A nucleotide consists of a nitrogen containing base, pentose sugar, and a phosphate group
Contain C, O, H, N, and P
Two types of Nucleic Acids: DNA and RNA

20. Deoxyribonucleic Acid (DNA)
Contains four nitrogenous bases:
adenine (A), guanine (G), cytosine (C) and thymine (T)
Double-stranded, helical
Replicates before cell division, ensuring genetic continuity
Provides instructions for the synthesis of proteins

21. Ribonucleic Acid (RNA)
Contains four nitrogenous bases:
adenine (A), guanine (G), cytosine (C), and uracil (U)
Contains uracil instead of thymine
Single-stranded
Mainly active outside of nucleus