Biological Molecules
3. Biological Molecules
- Importance of carbon
- Intro to carbon: organic compounds are C bonded to C or H
- Carbon chains: skeletons of organic molecules; tetravalent: 4 valence electrons; functional groups = R (gets replaced, causes different functions)
- Hydrocarbons (C and H)
- Nonpolar and uncharged = hydrophobic and insoluble in H2O
- Functional groups
| Name | Polar | Hydrophilic | Acidity | General info | |
|---|---|---|---|---|---|
| Hydroxyl (R-OH) | Alcohol | yes | yes | neutral | |
| Carbonyl (CHO) | Aldehyde /ketone | yes | yes | neutral | aldehyde/ketone depending on C=O location |
| Carboxyl (R-COOH) | Carboxylic acids | yes | yes | acid | Part of AA, H+ released easily |
| Amino group (R-NH2) | Amines (H+ easily accepted) | yes | yes | base | make up protein, can have different sides, H+ accepted easily |
| Sulfhydryl group (R-SH) | thiols | yes | yes | Slightly acidic | Hold some protein structure (2), SH form cross-link, < polar than hydroxyl |
| Phosphate group (R-PO4H2) | Organic phosphate | yes | yes | acid | Charge phospholipids and nucleic acids in DNA/RNA |
| Methyl group (R-CH3) | Methyl hydrocarbon | no | no | neutral | Control gene expression, shape/function of sex hormones |
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- Biological macromolecules
- Macromolecule: monomer is building block, joined to make polymers
- Carbohydrates, proteins, nucleic acids, NOT lipids (lipids form lipids)
- Dehydration synthesis with enzymes (dehydrogenase): remove H2O to join molecules
- Hydrolysis: to break with enzymes by adding H2O (hydrolase)
- Carbohydrates: monomer are sugars
- linear/ring forms (alpha/beta glucose); fuel and building material; sucrose = glucose + fructose
- Lipids
- Hydrophobic bc of hydrocarbons; made of glycerol (2 carbon alcohol: 3 OH) and 1-3 fatty acids
- Presence of double bonds determines if is saturated/unsaturated (kinks)
- Cell membrane is phospholipid: amphipathic (glycerol and 2 fatty acids, hydrophobic)
- Phosphate group: hydrophilic
- Steroids: 3 rings 6C and 1 ring 5C; side chains/functional groups vary; cholesterol in animals for communication and cell membrane structure; helps hold membrane together as temp. Fluctuates
- Cortisol is stress hormone
- Protein
- R group determines function/acidity/polarity
- Folding is necessary to become protein (3D shape)
- Primary: seq. Of AA joined by peptide bonds determined by DNA
- Secondary: H-bonds stick together (amino/carboxyl group)
- Tertiary: R-groups interact in polypeptide and fold into 3D shape; many bonds
- Quaternary: many polypeptides from 1 macromolecule
- Denaturation: loss of third/forth structure (bio. In-active due to pH/salt concentration/temperature
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| monomers/ components | polymers | function | Bond type | types | |
|---|---|---|---|---|---|
| carbs | glucose | disaccharide/ polysaccharide | storage(starch, glycogen, alpha glucose); structure (cellulose, chitin, beta glucose) | glycosidic | Glucose, fructose, sucrose |
| lipids | Glycerol, fatty acids | lipid | Energy storage (triglyceride), membrane (phospholipids), communication/membrane structure (steroid) | Ester linkage | Triglycerides, phospholipids, steroids |
| proteins | Amino acids | polypeptide/ protein | Body structure, enzyme reactions, energy transfer | Peptide bond | Primary, secondary, tertiary, quaternary |
| Nucleic acids | nucleotides | DNA/RNA | Transmit hereditary info, protein production | phosphodiester | DNA/RNA |
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