Biological Macromolecules enzyme Heba AlTamimi 1 Macromolecules Examples
Biological Macromolecules & enzyme Heba Al-Tamimi 1
Macromolecules ü Examples: 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids ü All of the above are polymers except lipids ü Polymers : formed by joining one or more building blocks called MONOMERS 2
Dehydration Synthesis • Polymers are formed by dehydration synthesis that involves removal of water HO H H 2 O HO H 3
Hydrolysis • Separates monomers by “adding water” HO H H 2 O HO H 4
Carbohydrates 5
Carbohydrates: Structure • Classfication • Monosaccharides: simple sugars (monosaccharides) • Ex. : glucose – Polymer (chain of units): complex carbohydrates (or polysaccharides) • Ex. : starch, cellulose, chitin, glycogen Disaccharide: 2 simple sugars bonded together
Carbohydrates Monosaccharide: one sugar unit Examples: glucose (C ( 6 H 12 O 6) Fructose Galactose glucose 7
Carbohydrates Disaccharide: double sugar Examples: – Sucrose (glucose+fructose) – Lactose (glucose+galactose) – Maltose (glucose+glucose) glucose 8
Carbohydrates Polysaccharides: polymers composed of many sugar building blocks Examples: starch glycogen cellulose glucose glucose cellulose glucose 9
Carbohydrates: Indicator Tests • Reducing sugars : Ø Benedict’s test is used as a simple test for detecting reducing sugars • Complex Sugars(Polysaccharides) Ø Lugol’s test /Iodine
5 -1 Benedict’s solution -Coo. H 1 - + Cu 2 O + Cu. SO 4/0 H (Red –brown precipitate) Maltose 2 - reducing Glucose + Galucose 11
Benedict’s solution Sucrose Non-reducing 3 Glucose + Fructose Lactose 4 - Non-reducing Glucose + Galactose 12
Benedict’s test glucose maltose sucrose starch H 2 O 2 cm Benedict 1 cm solution ØFill 5 of test tubes to I cm with following solution: {glucose, maltose, sucrose, starch & water} ØFill each of the test tube to the 3 cm mark with Benedict’s reagent ØPlace test tube in hot water bath (5 min) ØObserve color change 13
5 -2 The iodine test(lugol’s)for starch • Detect the presence of starch Ø Starch : glucose polymer Ø Glycogen: glucose polymer Ø Iodine potassium iodide, I 2 KI, interacts w coiled starch and becomes bluish black color So , form is important
iodine test(lugol’s) glucogen glucose sucrose starch H 2 O 2 drop Lugol’s 2 cm solution ØFill 5 of test tubes to I cm with following solution: {glucose, sucrose, starch , glucogen & water} ØAdd 2 drops of Iodine ØObserve color change 15
Negative Test Positive Test
Proteins 17
Proteins: Structure • Proteins are made up of… Ø Monomer (basic unit): amino acids • 20 different kinds! Amino acids linked by peptide bonds
Proteins Ø Ninhydrin test for amino acids (aas. ) aas. having free amino groups are readily detected with ninhydrin -> purple or violet Ø The Biuret test for polypeptide The amino group in one aas. is linked to carboxyl group on an adjacent aas. by a peptide bond üthis band is the site of action for the Biuret test for protein , Cu 2+must complex with at least four to six peptide bounds to produce violet color 19
5 -3 Ninhydrin test for amino acid albumin glycogen milk a. a H 2 O 5 drop ninhydrin + heat 2 cm solution ØFill 5 of test tubes to I cm with following solution: {albumin , glycogen, milk , a. a (glycine) & water} ØAdd drops of ninhydrin reagent ØPlace test tube in hot water bath (5 min) ØObserve color change Ø@ sink Skin irritation 20
The Biuret test for polypeptide albumin glycogen milk a. a H 2 O 2 cm Biuret 2 cm solution ØFill 5 of test tubes to 3 cm with following solution: {albumin , glycogen, milk , a. a (glycine) & water} ØFill each test tube to the 4 cm with Biuret solution and mix ØObserve color change 22
5 -4 The Biuret test for polypeptide 1% Cu. SO 4 -> Cu 2+ Complexes w at least 4 -6 peptide bonds and produces violet color 23
Lipids 24
Lipids: Structure • Fat is constructed from 2 kinds of smaller molecules : 1 -glycerol 2 -fatty acid • Lipids are not soluble in water, but soluble in organic solvents
Lipids “demo” 5 -6 Lipid Solubility test Lipids are insoluble in polar solvent and soluble in nonpolar solvent Ø Ø fill 2 tubes to the 2 cm mark with corn oil In First tube, add 5 ml of tap water In second tube, add 5 ml of mineral oil Detect solubility Ø 5 -5 Sudan red for fat (book) Ø Sudan red is a lipid soluble dye • Add 10 drops of Sudan red to tube number 1 in above experiment • Observe color , where is the red color found? 26
Nucleic Acids 27
Nucleic Acids: Structure • Nucleic Acids are made up of… – Monomers (basic units): nucleotides • Two types: Ø Deoxyribonucleic acid (DNA-double helix) Ø Ribonucleic acid (RNA-single strand)
5 -9 Dische diphenylamine test “demo” • In this test , acidic condition convert deoxyribose to a molecule that binds with diphenylamine to form a blue complex. Ø Ø Ø Ø Number 3 test tube 1 -3 Into tube 1, place 10 drops of banana DNA Into tube 2, place 10 drops of standard DNA Into tube 3, place 10 drops of distilled water Add 1 ml of diphenylamine regent Banana Place in a boiling water bath for 10 min Transfer the tubes to ice Observe color change. DNA Standard DNA water
Enzymes… 30
Enzyme Substrate(s) +enzyme Optimal conditions We will take 2 examples 1 - casein (protein milk)+Rennin 2 - catechol +catechol oxidase product(s) Optimal coagulation Optimal benzoquinone condition 31
Enzyme (Rennin) • Rennin is found in the stomach of young mammals • The enzyme coagulate the casein , a protein found in milk • Optimal condition Ø p. H = ~7 (neutral) Ø Temperate = 37 C 32
6 -1 Effect of temperature on enzyme activity Put 3 ml Rennin Place at 100 C for 5 min Place at 37 C for 5 min “Accurate measures” Add milk (2/3) full , then incubate to 37 C for 15 min 33
6 -2 Effect of p. H on enzyme activity Put 3 ml Rennin Add 3 ml HCl Add 3 ml Na. OH Add 3 ml H 2 O Add milk to each tube (2/3) full , then incubate at 37 C for 15 min 34
6 -4 Enzyme (Catechol oxidase) “demo” • Catechole oxidase is an enzyme that turns bruised or cut fruits and vegetables brown • Catechol is a clear chemical , when it reacts with oxygen in presence of the enzyme catechol oxidase , it forms the dark brown product , benzoquinone 35
Catechol oxidase “Demo” • Prepare 3 test tubes using the following table 36
Go To Work…… 37
- Slides: 36