Biology Video Notes: Macromolecules, Enzymes, Nucleic Acids, ATP, Water, and Ions

A set of flashcards covering monomers/polymerization, carbohydrates, lipids, proteins, enzymes, nucleic acids, ATP, water, and inorganic ions.

What are monomers and polymers, and how are they linked in biological molecules?

Monomers are small repeating units (e.g., glucose, amino acids, nucleotides); polymers are long chains formed by linking monomers via condensation reactions that release water; hydrolysis breaks bonds by adding water.

Name three monosaccharides and give their general formula; also note an isomer of glucose.

Monosaccharides: glucose, fructose, galactose; general formula CH2O; glucose exists as α- and β- anomers (isomers).

Give three examples of disaccharides and the monosaccharide components of each.

Maltose (glucose + glucose); Sucrose (glucose + fructose); Lactose (glucose + galactose).

Name the three main polysaccharides and a key characteristic of each.

Starch (plants; energy storage; amylose + amylopectin); Glycogen (animals; highly branched for rapid energy release); Cellulose (plants; structural; β-glucose chains).

What are triglycerides and phospholipids made from, and how do their solubilities differ?

Triglycerides: glycerol + three fatty acids; phospholipids: glycerol, two fatty acids, and a phosphate-containing head; triglycerides are nonpolar (insoluble in water); phospholipids are amphipathic with a hydrophilic head and hydrophobic tails.

Differentiate saturated and unsaturated fatty acids.

Saturated fatty acids have no double bonds between carbons; unsaturated fatty acids contain one or more double bonds.

What is indicated by a cloudy-white emulsion after the lipid emulsion test?

Presence of lipids in the sample (emulsion test).

What are the main features of amino acids and the bond that links them in proteins?

Amino acids have an amino group (–NH2), a carboxyl group (–COOH), and an R group; they are linked by peptide bonds formed by condensation; hydrolysis breaks peptide bonds.

Name the four levels of protein structure and a defining feature of each.

Primary: amino acid sequence; Secondary: α-helix or β-pleated sheet stabilized by hydrogen bonds; Tertiary: 3D folding via hydrogen bonds, disulfide bridges, ionic interactions, and hydrophobic interactions; Quaternary: multiple polypeptide chains.

Differentiate globular proteins from fibrous proteins with examples.

Globular proteins are compact and usually soluble (e.g., enzymes); fibrous proteins are long, insoluble, structural (e.g., keratin).

What indicates a positive Biuret test for proteins?

Purple/lilac colour after adding Biuret reagent (copper sulfate).

Describe the active site of an enzyme and the induced-fit model.

The active site is the region where substrates bind; the induced-fit model states the active site adjusts its shape to fit the substrate during binding.

List the main factors that can affect enzyme-catalyzed reaction rates.

Temperature, pH, substrate concentration, enzyme concentration, and inhibitors.

What are nucleotides composed of, and how are nucleic acid chains joined?

Nucleotides consist of a pentose sugar (ribose or deoxyribose), a phosphate group, and a nitrogenous base; chains are joined by phosphodiester bonds.

Differentiate DNA and RNA in terms of structure and function.

DNA is double-stranded and stores genetic information; RNA is single-stranded and involved in protein synthesis.

What is semi-conservative replication in DNA replication?

Each new DNA molecule contains one old (template) strand and one newly synthesized strand.

Describe the structure of ATP and what energy release during hydrolysis is used for.

ATP consists of adenine, a ribose sugar, and three phosphate groups; hydrolysis to ADP + Pi releases energy to power cellular processes.

List key properties of water that make it vital for biology.

Water is a polar solvent; high specific heat capacity; high latent heat of vaporisation; cohesive due to hydrogen bonding; supports metabolic reactions.

Name important inorganic ions and one key role for each.

H+ determines pH; Fe2+/Fe3+ in haemoglobin for oxygen transport; Na+ involved in nerve impulses and co-transport; PO43- in ATP, nucleic acids, and phospholipids.

Identify four key covalent bonds found in biological macromolecules and give an example for each.

Glycosidic bond (carbohydrates); Ester bond (lipids); Peptide bond (proteins); Phosphodiester bond (nucleic acids); Hydrogen bonds stabilize structures (e.g., protein secondary structure, DNA).