Biology Notes (Exam Guide 3)

carbon

• 4 single valence e-, tetravalent

organic compounds

contain carbon bonded to C or H

carbon chains

skeletons of organic compounds

structure is key to molecular function 

functional groups (R)

set of molecules that changes the whole function when added to another

• different functional groups change molecular function

hydrocarbons

carbon and hydrogen

• non polar and uncharged = hydrophobic = insoluble in H20

functional groups

1. hydroxyl (R-OH)

2. carbonyl (CHO)

3. carboxyl (R-COOH)

4. amino  (R-NH2)

5. phosphate  (R-PO4H2)

6. methyl (R-CH3)

1. Hydroxyl (R-OH)

• polar

• hydrophilic

• neutral acidity

2. Carbonyl (CHO)

• polar

• hydrophillic (less than -OH)

• neutral acidity

3. Carboxyl (R-COOH)

• polar

• hydrophilic

• is acidic

• carboxylic acids (H+ is easily released)

4. amino (R-NH2)

• polar 

• hydrophilic 

• not acidic 

• amines (H+ is easily accepted)

5. phosphate  (R-PO4H2)

• polar

• hydrophilic

• acidic

• organic phosphate

• negative charge, phospholipids and nucleic acids (DNA, RNA)

6. methyl (R-CH3)

• not polar 

• hydrophobic 

• neutral acidity 

• control gene expression 

• shape and function of sex hormones 

monomers

building blocks of macromolecules

• join monomers together to form polymers

polymers

many monomers joined together

3 out of 4 biological molecules are polymers

carbohydrates, proteins, and nucleic acids

• lipids are biological molecules but never polymers

dehydration synthesis

remove water and joins

• enzymes used are dehydrogenases

hydrolysis

adds a water and breaks

• enzymes used are hydrolyses 

macromolecules

1. carbohydrates (CH20)

2. lipids

3. proteins

4. nucleic acids

1. Carbohydrates (CH20)

• Monomer= sugars(monosaccharides) and glucose

• polymer= polysaccharides, fuel and building material 

- glucose, linear and ring form makes rings form in two ways a of B glucose 

- a covalent bond between monosaccharides = glycosidic linkage if it’s 2 monomers = disaccharide 

-if two or more monomers in a chain, sugar polymers= polysachorides (depends on type of monomer and type of glycosidic linkage which functions as energy or structural support 

2. Lipids 

• not polymersr

• hydrophobic (mostly hydrocarbons)

• 3 types:

- fats, which functions as an energy source and are made up of glycerol and 1 2 3 fatty acids 

- phospholipids= cell membranes 

- steroids, which are made ups of 3 rings of 6 Carbon and 1 ring of 5 Carbon, and the side chains or functional groups vary 

amphipathic

glycerol + 2 fatty acids (hydrophobic) and phosphate group (hydrophilic 0

cortisol

stress hormone

3. proteins

• peptide bonds between amino acids (monomers) dehydration synthesis reaction

• polypeptide is a sequence of amino acids

- each AA is bound to the next with a peptide bound but it must be folded into correct 3d shape to become a protein

• it’s structure is a sequence of amino acids joined by peptide bonds in polypeptide chain, determined by DNA

• it’s secondary structure: within a single polypeptide hydrogen bonds stick AAs together (amino group, carboxyl group)

- R groups do not participate

• tertiary structure: within a single polypeptide R- groups interact folds into a particular 3D shape, all types of bounds

• quaternary structure: multiple polypeptide chains form one macromolecule (no more folding)

denaturation 

loss of a protein’s 3rd or 4th structure 

• a dentured protein is biologically inactive, pH, salt concentration, and temperature 

4. nucleic acids

monomers are nucleotides and there are 2 classes: DNA and RNA, which transmit hereditary info and determine protein production