Ch. 3 The Four Most Important Organic Biological Compounds 1.Carbohydrates 2.Lipids 3.Proteins 4.Nucleic Acids
C:H:O ratio is 1:2:1 (CH 2 0)n Simple sugars: glucose, fructose Structural units, used to make larger, storage compounds: 1.Starch – energy storage in plants 2.Glycogen – energy storage in animals 3.Cellulose – plant cell walls (structure, protection) 1) Carbohydrates
Fig 3.7
Glucose Fructose Formation of a Disaccharide C 12 H 22 O 11 GlucoseFructose H 2 O (water) Sucrose A portion of a polysaccharide Monosaccharides C 6 H 12 O 6 (Simple sugars)
2. Lipids Non-polar, hydrophobic (don’t dissolve in water) (CH) n COOH Functions: –High-energy storage molecules –Transmit signals/messages (steroid hormones) 4 main types: a)Fats b)Phospholipids c)Steroids d)Waxes
A) Fats Triglycerides – most abundant lipids in body, abundant energy!
Fig. 3.8B,C
-no double bonds-has double bonds
B) Phospholipids -cell membranes
C) Steroids No fatty acid chains Cholesterol: –component of cell membranes –Precursor for hormones (estrogen, testosterone) Fig 3.9B Cholesterol
D) Waxes Repel water Protect & lubricate Plant cuticle honeycombs
3) Proteins Made of amino acids joined by peptide bonds enzymes cell parts like hair, nails, muscle fibers. Cell membrane transporters Fig. 3.12A
Fig 3.12C
Proteins continued DNA specifies the order of AA Order determines shape Shape determines function
Primary structure
Fig 3.14A-D
One AA substitution alters the form of hemoglobin, resulting in sickle cells. Anemia, circulatory problems, kidney failure, enlarged spleen…..
4) Nucleic Acids DNA & RNA –Sequence is the code for protein synthesis Monomers of Nucleotides Fig 3.16A
The nitrogenous bases of DNA
RNA contains: ribose instead of deoxyribose, and uracil instead of thymine
Fig 3.16B,C: The structure of DNA