Biological Molecules and Processes

Flashcards covering basic biochemistry including monomers, polymers, carbohydrates, lipids, proteins, enzymes, nucleic acids, ATP, and inorganic ions as described in the lecture notes.

Monomers

Small units which are the components of larger molecules, such as monosaccharides, amino acids, and nucleotides.

Polymers

Molecules made from many monomers joined together.

Condensation reaction

A chemical reaction where monomers are joined by a chemical bond and a water molecule is eliminated.

Hydrolysis

A process where water is added to break a chemical bond between two molecules.

Monosaccharide

A single monomer sugar unit with the general formula $(CH_2O)_n$ where $n$ is between three and seven.

Glycosidic bond

A chemical bond formed between two saccharides during a condensation reaction.

Glucose

A monosaccharide with six carbon atoms existing as two isomers, alpha and beta, which serves as the main substrate for respiration.

Maltose

A disaccharide formed by the condensation of two glucose molecules.

Sucrose

A disaccharide formed by the condensation of glucose and fructose.

Lactose

A disaccharide formed by the condensation of glucose and galactose.

Glycogen

The main energy storage molecule in animals made of alpha glucose joined by $1,4$ and $1,6$ glycosidic bonds.

Amylose

An unbranched chain of glucose molecules in starch joined by $1,4$ glycosidic bonds, forming a coiled, compact structure.

Amylopectin

A branched polysaccharide in starch made of glucose units joined by $1,4$ and $1,6$ glycosidic bonds.

Cellulose

A component of plant cell walls made of long, unbranched chains of beta glucose joined by glycosidic bonds.

Microfibrils

Strong threads made of long cellulose chains running parallel and joined by hydrogen bonds.

Benedict’s reagent

An alkaline solution of Copper(II) Sulfate used to test for reducing sugars; it forms an insoluble red precipitate of copper (I) oxide when positive.

Triglycerides

Lipids composed of one molecule of glycerol and three fatty acids joined by ester bonds.

Saturated lipids

Lipids that do not contain any carbon-carbon double bonds, typically found in animal fats.

Unsaturated lipids

Lipids containing carbon-carbon double bonds which cause the molecule to bend and remain liquid at room temperature.

Phospholipids

Polar lipids where one fatty acid is replaced by a phosphate-containing group, resulting in a hydrophilic head and hydrophobic tails.

Emulsion Test

A test for lipids involving mixing a sample with ethanol and then water; a cloudy-white colour indicates a positive result.

Amino acids

Monomers of proteins containing an amino group ($NH_2$), a carboxylic acid group ($-COOH$), and a variable R group.

Peptide bond

The chemical bond formed between amino acids during a condensation reaction.

Primary structure

The specific order and number of amino acids in a protein chain.

Secondary structure

The shape an amino acid chain takes, such as an alpha helix or beta pleated sheet, maintained by hydrogen bonds.

Tertiary structure

The 3D shape of a protein formed by further folding and maintained by disulfide bridges, ionic bonds, and hydrogen bonds.

Biuret Test

A biochemical test for proteins using sodium hydroxide and dilute copper (II) sulfate; a purple colour indicates peptide bonds.

Enzymes

3D tertiary structured globular proteins that increase the rate of reaction by lowering the activation energy.

Induced fit model

A model of enzyme action where the active site's structure is altered to fit around the substrate during binding.

pH formula

$pH = -\log_{10}[H^+]$.

Nucleotides

Components of DNA and RNA consisting of a pentose sugar, a nitrogen-containing organic base, and a phosphate group.

Phosphodiester bond

The condensation-formed bond between the deoxyribose sugar of one nucleotide and the phosphate group of another.

DNA helicase

The enzyme that separates DNA strands by breaking hydrogen bonds between complementary bases during replication.

DNA polymerase

The enzyme that joins activated nucleotides together with phosphodiester bonds during DNA replication.

ATP (Adenosine triphosphate)

A nucleotide derivative made of ribose, adenine, and three phosphate groups used as an immediate energy source.

Hydrogen ions

Inorganic ions that determine the pH of substances; increased concentration results in lower pH.

Iron ions

Ions that serve as a component of haemoglobin for oxygen transport in red blood cells.