1. Chapter 3 Biological Molecules

2. 3.1 Synthesis of Molecules

3. Chemical Reactions
Metabolism: all chemical reactions by which cells acquire and use energy
Condensation or synthesis: builds a large molecule from smaller subunits; water is released
Hydrolysis: uses water to break a molecule into smaller subunits
Monomers: subunits of larger molecules
Simple sugars, fatty acids, amino acids, and nucleotides
Polymers: consist of multiple monomers

5. 3.2 Carbohydrates

6. Simple Sugars
Carbohydrate: organic compound that consist of carbon, hydrogen, and oxygen in a 1:2:1 ratio
Monosaccharides: simplest type of carbohydrates:
Glucose, fructose, ribose
Cells use monosaccharides for cellular fuel
Monosaccharides are also used as:
Precursors for other molecules
Structural materials to build larger molecules

8. Synthesis between simple sugars
Disaccharides: two monosaccharides
Lactose: glucose + galactose
Sucrose: glucose + fructose
Polysaccharides: chains of hundreds or thousands of monosaccharide monomers
Cellulose, Starch, Glycogen

10. 3.3 Lipids

11. Non-polar organic molecules
Lipids: fatty, oily, or waxy organic compounds
Lipids contain fatty acids: consist of a long hydrocarbon “tail” with a carboxyl group “head”
The tail is hydrophobic
The head is hydrophilic
Fats: lipid that consists of a glycerol molecule with one, two, or three fatty acids
Saturated (solid) fats and Unsaturated (oily) fats

13. Other lipids Phospholipid: main component of cell membranes
Contains phosphate group (hydrophilic) and two nonpolar fatty acid tails
In a cell membrane, phospholipids are arranged in two layers called a lipid bilayer
Steroids: lipids contain a rigid backbone of carbon atoms arranged in four rings
Cholesterol, estrogen and testosterone

16. 3.4 Proteins

18. Amino Acids
Twenty kinds of monomers called amino acids
An amino acids contain a side chain called an “R group” defines the kind of amino acid
The covalent bond that links amino acids is called a peptide bond
Proteins are polypeptides or hundreds to thousands of amino acids

20. Protein Structure determines Function
Primary structure: linear series of amino acids
Secondary structure: the twists and folds of a polypeptide chain
Tertiary structure: regions of protein adjoin to create compact domains
Quaternary structure: two or more polypeptide chains joined together

24. Denaturization
Heat, shifts in pH, salts or detergents can denature (unfold) a protein by breaking hydrogen bonds
Denaturation causes a protein to lose its function

25. 3.5 Nucleic Acids

26. Nucleotides
Nucleotide: a 5 carbon sugar bonded to a nitrogen- containing base and one, two, or three phosphate groups
Example: ATP (adenosine triphosphate); an energy carrier in cells
Polynucleotides in which the sugar of one nucleotide is bonded to the phosphate group of the next
RNA (ribonucleic acid
DNA (deoxyribonucleic acid