CARBOHYDRATES ▪ One of the ways to categorize it is according to the number of carbon

▪ Key source of energy used by living things molecules (cannot exist beyond 7)
▪ Serve as extracellular structural elements in ➢ Trioses (C-3)
cell wall of bacteria and plant ➢ Tetroses (C-4)
▪ Polyhydroxy aldehydes or polyhydroxy ketones ➢ Pentoses (C-5)
▪ General formula is Cn(H20)n or ➢ Hexoses (C6)
C6H1206; hence the name ➢ Heptoses (C-7)
hydrates of carbon ▪ Can also be classified as ketoses or aldoses
▪ In human body, the D-
KETOSE SUGAR/POLYHYDROXYKETONES
glucose is used
▪ Simple sugar ends with —ose ▪ A ketose contains a carbonyl group attached to two R groups having
one or more hydroxyl groups
▪ Ex. Fructose, Ribulose
Classification of carbohydrates
ALDOSE SUGAR/POLYHYDROALDEHYDES
Number of sugar units – how many molecules of carbohydrates is present
▪ Aldose contains terminal aldehyde group in addition to R group
1. Simple sugar – one unit containing – OH
▪ Monosaccharides contain one monosaccharide unit ▪ Ex. Glucose, Ribose, Galactose
2. Complex sugar - more than two unit
▪ Disaccharides contain two monosaccharide units
▪ Oligosaccharides contain 3-9 monosaccharide units
▪ Polysaccharides can contain more than 9 monosaccharide units
➢ Complex carbohydrates can be broken down into smaller sugar units
through a process known as hydrolysis
MONOSACCHARIDES
▪ They can be classified by the number of carbon atoms
 Cyclization of ring formation of monosac
Monosaccharides exists in their cyclic/ring forms more than their
acyclic/open chain configuration
▪ In aldoses, cyclization occurs to form a 6-membered ring (pyranose)
via:
FRUCTOSE
A.) – OH group of carbon #5 reacts with carbon #1 (carbonyl carbon; C=O)
▪ Also known as levulose or “fruit sugar”
B.) One of the double bonds of = O attached to the carbon #1 bonds with the ▪ Component of sucrose (table sugar)
– H from the – OH of the carbon #5 ▪ Sweeter than sucrose
▪ In ketoses, cyclization occurs to form a 5-membered ring (furanose) ➢ Used as sweetener (high fructose corn syrup) for beverages and
via the ff steps: prepared foods

A.) – OH group of carbon #5 reacts with carbon #2 (carbonyl carbon; C=O)

B.) One of the double bonds of = O attached to carbon #2 forms a bond with
the -H from the – OH of carbon #5

IMPORTANT MONOSACCHARIDES GALACTOSE

GLUCOSE ▪ Component of milk sugar (lactose)
▪ Also known as dextrose ▪ Present in plant cells
▪ Most important because it is the only sugar that the brain can only
utilize
▪ Most important simple carbohydrate in human metabolism
➢ Provides the starting material for metabolism (acetyl CoA for
TCA)
▪ Component of sucrose (table sugar)
RIBOSE & 2-DEOXYRIBOSE Polysaccharides
▪ Tens, hundreds of monosaccharides linked together by glycosidic
▪ Component of RNA (ribonucleic acid) and DNA (deoxyribonucleic
bonds
acid)
▪ Ex. of important polysaccharides
▪ Cellulose
▪ Provides structure to plants
▪ Not digested by human beings
▪ Starch
▪ Energy storage for plants
DISACCHARIDES
▪ Digestible by humans
▪ 2 monosaccharide units
▪ Composed of: Amylose and Amylopectin
▪ Linked together by glycosidic bonds
▪ Glycogen
▪ Energy storage for animals

▪ Ex. of important disaccharides:

➢ Sucrose – table sugar
➢ Lactose – milk sugar
➢ Maltose – malt or beer sugar
 Proteins PEPTIDE BOND FORMATION
▪ Proteins are derived from the Greek protas meaning “of primary ▪ Forms two amino acids for proteins
importance” ▪ Release of water
▪ Made up of folded polypeptide chains
▪ 20 amino acid groups *Bond of 2 amino acids with peptide bond
▪ Complex, high-molecular-weight molecules
▪ Biochemical molecules that consist of amino acids joined by peptide
bonds
▪ Proteins can be hydrolyzed by acids, bases, or specific enzymes
▪ Proteins are probably the most important of biochemical molecules

GENERAL STRUCTURE OF AMINO ACIDS

▪ A central carbon atom is attached to
an ammonium group, a carboxylate HIERARCHICAL ORGANIZATION OF PROTEINS
group
PRIMARY STRUCTURE
▪ Amino acid is special in its
biochemistry because it ▪ Amino acid sequence along a
deprotonates (releases H+) and it linear polypeptide chain
makes the protein acidic ▪ Contains ALL the info necessary
▪ Deprotonate – release of H+ (acidic) for higher orders of sctructure
▪ Protonate – released of OH (basic)
▪ Zwitterionic Property – can perform
neutralization (addition of acid with
base)
SECONDARY STRUCTURE
▪ Local conformation of the polypeptide chain
▪ Formed by Hydrogen-bond interactions of adjacent amino acids
▪ Forms 3 domains: a-helices, b-strands, o-loops
▪ Interfaces are composed of hydrophobic residues
▪ Packs to form structural domains
Protein folding process
1. Secondary structures form
2. Hydrophobic Collapse (non-polar amino acids aggregate)
3. Long range interactions between secondary structures cause further
folding to occur
TERTIARY STRUCTURE ▪ Throughout this process, there may be one or more intermediate
states named molten globule
▪ 3D organization of the secondary structural elements
▪ Protein folds

Three basic classes of proteins distinguished by shape and solubility

1. Globular – spherical, marginally stable that facilitates motion, highly
soluble
2. Fibrous – simple linear, structural roles, insoluble
QUATERNARY STRUCTURE
3. Membrane – associated with cell membrane
▪ Multiple subunits associate to form a multimeric complex
▪ Can function independently or cooperatively
▪ Found in proteins that have two or more interacting polypeptide
chains, termed subunits
 DENATURATION OF PROTEINS DISACCHARIDES – 2 UNIT
▪ Disruption of secondary, tertiary, and quaternary structure of proteins
leading to loss of their biological activity
▪ Reversed process
▪ WHY? Because we need to repurpose the amino acid chain
POST LAB discussion
CARBOHYDRATES
POLYSACHARIDES - > 2
▪ Carbohydrates are stable at cold temperature/house temperature
▪ Formation of carbohydrates in plants is GLUCOSE to STARCH
▪ While for animals, STARCH to GLUCOSE
▪ Glucose are single units/ monosaccharides
▪ Glycosylic bond = Bonds 2 Disaccharides
MONOSACHARIDES – 1 UNIT

ENERGY STORERS
➢ 1,4 glycosylic Linkage (ORANGE)
▪ non-dietary fibers
▪ Ex. malunggay, corn
➢ 1,6 Glycosylic Linkage (BLUE)
▪ aminopeptid carbohydrates
▪ has branching, panning out
▪ Ex. rice, mochi, tikoy, kamote
 EXP 4. EXTRACTION OF CARB FROM PLANT CELLS
▪ Grinding (Breakdown of plant cells) MOLISCH TEST (PRESENCE OR ABSENCE OF CARBOHYDRATES)
▪ Pulverizing (Breakdown of plant cells) SAMPLE OBSERVATIONS PRESENCE OF
▪ Precipitation (Rendering carbohydrates insoluble in water) CARBOHYDRATES
▪ Washing of Precipitates Glucose
Sucrose Purple ring on the Positive
➢ Ethanol deactivates enzyme that causes oxidation (enzymatic Starch interface
browning) and allows starch to dry faster Ripe banana
➢ Carbohydrates Milk
are more stable Energy Drink Colorless Depends if high on sugar
at cold (fizz)
temperature. It Unsweetened Gelatin Colorless Negative
will turn
GELATINOUS if TEST INFERENCE POSITIVE RESULT REAGENT
exposed to high Molisch’s Test Presence of Presence of purple a-naphthol
temperature Carbohydrates ring at the
interface
BENEDICT’S TEST Benedict’s Test Presence of Reducing Brick-red CuSO4 in
Sugar Precipitate NaCitrate

Iodine Test Presence of Starch Purple solution Iodine

 BENEDICT’S TEST (PRESENCE OR ABSENCE OF REDUCING SUGARS)
SAMPLE COLOR REACTION PRESENCE OF REDUCING PROTEINS and amino acids
SUGARS
➢ Molecular weight = 16
Glucose Brick-red precipitate Positive
➢ Carboxylic Group
Sucrose Blue solution Slightly positive (non- ▪ H+ = less important
reducing) ▪ Acidic because H+ can be easily let go of
Starch Blue solution Negative (non-reducing) ➢ Amino group
TEST FOR STARCH OR IODINE TEST (PRESENCE OR ABSENCE OF STARCH) ▪ N (nitrogen) can absorb H
SAMPLE COLOR REACTION PRESENCE OF STARCH ▪ Basic because of the formation of OH
▪ The H+ from the carboxylic group is absorbed by N
Starch (reference) ➢ PEPTIDE BOND – bond that holds amino acid together that
Ripe banana Purple Solution Positive helps in the stability of the protein structure
Milk - Slightly Positive
Energy Drink - Depends on fizz BASIC STRUCTURE OF AMINO
Orange Juice - Positive (Pulp) ACID
TEST FOR STARCH a. Insoluble Proteins
▪ Proteins in the body that
are capable in building
new structures in the body
▪ Water insoluble (hydrophobic)
▪ Ex. collagen, keratin
b. Soluble Proteins
▪ Transport proteins
▪ Soluble in water EXTRACTION OF PROTEINS
▪ Ex. enzymes, hormones
✓ Introduction of acetate buffer
WHAT DETERMINES IF INSOLUBLE OR SOLUBLE? ➢ For protein crystallization and staining gels used in protein
electrophoresis
➢ R group decides if protein is insoluble or soluble
➢ To prevent pH changes that might affect the biochemical activity
➢ If the amino acid is non-polar, it can form water insoluble proteins
of compounds
Water Insoluble Proteins/Non-polar AA ▪ Ethanol – dehydrates proteins
▪ Hexane – removes all fat-soluble components
▪ Methionine
▪ Leucine TEST FOR PROTEINS
▪ Isoleucine HEAT TEST
▪ Valine
▪ Alanine ➢ Coagulation Test – destroying the quaternary level (main function) of
▪ Glycine protein structure
▪ Proline WHAT COAGULATES PROTEINS?
▪ Phenylalanine ▪ Heavy metals – HgCl2 mercury chloride
Water Soluble/Transport Proteins ▪ Mineral acids – HNO3 nitric acid
▪ Dry heat
Serine Glutamine
Threonine Histidine Inference: Formation of white gelatinous suspension
Cysteine Lysine
Tyrosine Arginine ➢ Denaturation Test – destroying the secondary level (domain) of protein
Tryptophan structure
Aspartic Acid
Glutamic Acid ➢ Colorimetric Test – determines the concentration of analyte through
Asparagine comparing color changes
XANTHOPROTEIC TEST

MILLON’S TEST
QUESTIONS 7. What possible type of sample would yield a positive result in Biuret test
1. What possible type of sample would yield a positive result in Millon’s ✓ A sequence of polypeptides suspended in acetate buffer
Test?

✓ A solution of suspended amino acid

2. What possible effect will it have on the sample if acetate buffer is

added

✓ It will precipitate the protein

3. What possible effect will it have on the sample if hexane is added

✓ Washes off water soluble impurities

4. What possible effect will it have on the sample if ethanol is added on

carbohydrates

✓ Deactivates enzyme that promotes enzymatic browning

5. What possible type of sample would yield a positive result in Benedict’s

Reagent yielding a brick-red precipitate

✓ Glucose solution

6. What possible effect will it have on the sample if sulfuric acid is added

✓ Oxidizes the sample and form a five-membered ring derivate