Download Outline03 Biomolecules

Biology 219 – Human Physiology
Biomolecules
Clemens
Text: Ch 2
A. Carbohydrates
 general formula: (CH2O)n
e.g., glucose - C6H12O6
 soluble in H2O (many polar –OH groups)
 major energy source for most cells; required by CNS
1. Monosaccharides (simple sugars)
- energy metabolism: glucose + 6 O2 → 6 CO2 + 6 H2O + energy (→ ATP)
- building blocks of polysaccharides and nucleotides
ring structures:
O
pentoses (5C) ribose, deoxyribose
hexoses (6C) glucose, galactose, fructose
O
2. Disaccharides
maltose = gluc–gluc; sucrose = gluc–fruc; lactose = gluc–galac
3. Polysaccharides
- energy storage molecules
starch (plants)
glycogen (animals, stored in liver and muscle)
- structural polysaccharides
cellulose (plant fiber)
chitin
GAGs (connective tissues - EC matrix)
B. Lipids
 mostly non-polar organic molecules
 rich in C-H and C-C bonds
 low solubility in H2O
1. Fatty acids - basic building blocks of lipids
long-chain hydrocarbons with carboxyl end
COOH
saturated fatty acids: contain all C-C single bonds
- hydrocarbon chains pack closely → more solid (e.g., animal fat)
unsaturated fatty acids: contain C=C double bond(s) (monounsaturated, polyunsaturated)
- “kink” in the chain → more liquid (e.g., vegetable oil)
2. Triglycerides (triacylglycerols)
3 fatty acids + glycerol
- energy-rich molecules (= high in calories)
~ 2X more energy than carbohydrates per gram
- insoluble in H2O
- body fat (adipose tissue) functions for energy storage
3. Phospholipids
2 fatty acids + glycerol + phosphate group
- amphipathic molecules - polar (head) and non-polar (tail) ends
e.g., phosphatidylcholine (lecithin)
- phospholipid bilayer forms the basic structure of the plasma membrane
phospholipid heads contains charged/polar phosphate groups
non-polar tails contain saturated and unsaturated fatty acids
4. Steroids
cholesterol and derivatives; 4-ring structure
- cholesterol is a component of the cell membrane
- steroid hormones: cortisol, aldosterone, testosterone, estrogen
5. Eicosanoids
modified fatty acids with a ring (e.g., prostaglandins)
- function in intercellular signaling (paracrine agents)
- vasomotor effects (constriction or dilation), inflammation, pain
Biology 219 – Human Physiology
C. Amino Acids and Proteins
1. Amino acids
Clemens
H
H2N-C-COOH
R
contain amino group, carboxyl group, central C atom, H atom, R group
- R groups are variable: non-polar, polar, acidic (neg. charged), basic (pos. charged)
- 20 different R groups → 20 different amino acids in proteins
2. Peptides and polypeptides
polymers of amino acids
- chains formed by amino-carboxyl links
- peptide bond - strong covalent bond joins adjacent a.a.s
- R groups stick out from the chain
3. Proteins
> 50 amino acids, complex 3-dimensionalstructure:
primary (1°) structure - “linear” amino acid sequence (peptide bonds)
secondary (2°) structure - simple coiling/folding of the chain, e.g., alpha helix (H bonds)
tertiary (3°) structure - higher order 3-dimensional folding (R-group interactions)
quaternary (4°) structure - interaction among multiple protein subunits
D. Nucleotides and Nucleic Acids (DNA and RNA)
- information molecules
- store and transfer genetic information
1. Nucleotides - 3-part molecule, building blocks of DNA and RNA
a. pentose sugar
b. phosphate group
c. nitrogenous base
purines (double ring): adenine (A), guanine (G)
pyrimidines (single ring): cytosine (C), thymine (T), uracil (U)
2. DNA
- sugar = deoxyribose
S-A T-S
- double stranded, double-helix
P
P
sugar-phosphate covalent bonds form “backbone”
S-G C-S
bases point inward
P
P
- base pairing: A=T
S-C G-S
G≡C
P
P
hydrogen bonds between complementary bases
S-T A-S
3. RNA
- sugar = ribose
- mostly single stranded (higher-level structures in tRNA and rRNA)
- base pairing: A=U, G≡C
Classes of RNA
messenger (mRNA)
transfer (tRNA)
ribosomal (rRNA)
4. Other nucleotides/ nucleotide derivatives
ATP - energy “currency” molecule
GTP, cAMP - regulatory and cell signaling molecules
NADH, FADH2 - coenzymes, carriers of electrons and H in cellular respiration