lecture 2 - chemical calculations Flashcards
What is a monomer? Give examples.
A monomer is the basic unit of polymers.
Examples:
• Monosaccharides (glucose) • Amino acids (proteins) • Nucleotides (DNA)
Define a polymer and explain how it forms.
A polymer is a long molecule made of repeating monomers, formed by condensation reactions, which create bonds and release a water molecule.
What is a condensation reaction?
A reaction that joins two monomers by forming a chemical bond and eliminates a water molecule.
What is hydrolysis?
The process that breaks down polymers into monomers using a water molecule.
Name the elements present in carbohydrates.
Carbon (C), Hydrogen (H), and Oxygen (O).
What are the types of carbohydrates?
• Monosaccharides: Simple sugars (glucose).
• Disaccharides: Two monosaccharides (e.g., sucrose = glucose + fructose).
• Polysaccharides: Starch, glycogen, cellulose.
How is glycogen adapted for energy storage?
It has many side branches, allowing quick energy release, and is compact for storage.
What is the structure of proteins
• Monomer: Amino acids.
• Formed by peptide bonds through condensation reactions.
• Dipeptides (2 amino acids), polypeptides (many amino acids).
Describe the difference between saturated and unsaturated fatty acids.
• Saturated: Single bonds, straight chains.
• Unsaturated: Double bonds, kinks in the chain.
What is the structure of a triglyceride?
Glycerol bonded to three fatty acids by ester bonds (formed in a condensation reaction).
What is the role of phospholipids in cells?
• Form cell membranes.
• Phosphate head: Hydrophilic (water-attracting).
• Fatty acid tails: Hydrophobic (water-repelling).
Which test identifies reducing sugars?
Benedict’s test: Blue solution turns brick-red if reducing sugars are present.
How is starch tested?
Using iodine: Changes from yellow-brown to blue-black if starch is present.
Describe the Biuret test for proteins.
Add Biuret solution: A purple color indicates the presence of proteins.
What test is used to detect lipids?
Emulsion test: Mix with ethanol and water; a cloudy-white layer confirms lipids.
