Macromolecules of the Cell

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1.Carbohydrates
Consists of CnH2xOx
• Include sugars
• Classified into groups based on the number of carbon atoms per molecule. • Classes of Carbohydrates
o Monosaccharides
▪ Simple sugars
o Disaccharides
▪ Compound sugars
o Polysaccharides
▪ Complex sugars

a. Monosaccharides
• Simple sugars
• Contain about 3 to 6 carbon atoms per molecule
o Trioses
▪ The three carbon simple sugars
o Pentoses
▪ The five carbon simple sugars
▪ Examples are – Ribose and Deoxyribose o Hexoses
▪ The six carbon simple sugars
▪ Chemical formula for hexoses is C6H12O6 ▪ The most abundant sugars in nature. They comprise both disaccharides and polysaccharides. ▪ Examples are Glucose, Galactose and Fructose. o

• Isomers
• Chemicals that share the same chemical formula but different structures (mirror images) •
• Glucose “the blood sugar”
• The primary source of energy in all living things

• Galactose

• Fructose “fruit sugar”

Isomerization
A chemical reaction in which a substance is rearranged to form another substance.

Hydrolysis
Is a chemical reaction by which a large substance is broken down into smaller units through the addition of water.

Dehydration synthesis
Is a chemical reaction by which a large substance is manufactured from subunits with the release of water.

b. Disaccharides
Compound sugars
A simple sugar + a simple sugar will undergo dehydration synthesis to form a compound sugar plus water Each disaccharide is a product of dehydration synthesis including two hexoses. • Glucose + Glucose dehydration synthesis Maltose + water • Glucose + Galactose dehydration synthesis Lactose + water • Glucose + Fructose Dehydration synthesis Sucrose + Water

Glycosidic Bond
Electromagnetic force that joins hexoses together on a chain. Examples: Alpha and Beta glycosidic bonds.
Sugars end in “ose”
Enzymes end in “ase”

Lactose Intolerance
A condition that results from inability to produce Lactase, the enzyme needed for the digestion of lactose.

Milk Allergy
An immune reaction to one of the animal proteins in milk.

c. Polysaccharides
complex sugars
• A polysaccharide is polymer in which glucose units are the monomers. • A polymer is a chain of repeating units
• The repeating units of a chain are monomers
Examples of polysaccharides
• i. Starch “plant starch”
o form of glucose in plants
• ii. Glycogen “Animal starch”
o Storage form of glucose in animals
o Stored in the muscle and liver
• iii. Cellulose
• A polysaccharide that constitutes the cell wall of plants. It is a major component of dietary fibers. • The glucose molecules in cellulose, are held together by beta glycosidic bonds.

Advantages of dietary fibers
• Serves as buffers
• Function as roughage in the digestive tract
• Help reduce blood cholesterol
• Prevent diverticulosis
• Help prevent colon cancer
• Help prevent hemorrhoids
• Regulates bowel movement

iv. Chitin
A polysaccharide that constitutes the cell wall of fungi, as well as forming the exoskeleton of insects and crustacean.

v. Peptidoglycan
A polysaccharide that constitutes the cell wall of bacteria
It is composed of an altering sequence of two glucoselike units, NAG (N-Acetyl glucosamine) and NAM (N-Acetyl Muramine), impregnated by several amino acid bridges. -unlike the gram-positive bacterial cell wall, gram-negative bacterial cell wall is covered by a thick layer of lipids that resists penetration by penicillin.

Function groups
Acid or...
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