Biochemical Reactions: Monomers, Polymers, and DNA

• Biochemical reactions include studying the formation of monomers and polymers.
• Analyzing carbohydrates for their energy content/food storage is a component of biochemical reactions.
• Biochemical reactions also include the study of DNA replication and how it transmits and conserves the genetic code.
• Protein synthesis is also explained in these reactions.

Biochemical Reactions

• Condensation reaction: Building up polysaccharides, lipids, and polypeptide molecules, joining small molecules to form large molecules.
• Hydrolysis reaction: Breaking down polysaccharides, lipids, and polypeptide molecules; breaking down large molecules to form small molecules using water.
• DNA replication: DNA makes identical copies (replicas) of itself to pass on the daughter cells (new cells) before cell division.
• Protein synthesis: DNA encodes for the production of amino acids and proteins. Bases on DNA are transcribed and translated into proteins.

Condensation

• Links small biochemical building blocks to form larger molecules.
• Condensation is known as a 'dehydration' reaction because water is lost when two small molecules join.
• An example is when two amino acids join to form a peptide, water is the by-product.
• Starch produced by plants is via condensation reaction.

Hydrolysis

• Hydro = water and lysis = break.
• Large molecules break down into smaller biochemical building blocks.
• Hydrolysis is a 'hydration' reaction because it utilises water.
• Starch is hydrolyzed into glucose during digestion.
• Fats are broken down into fatty acids and glycerol.
• Proteins are broken down into amino acids.

DNA Replication

• This is the process where DNA makes an exact copy of itself.
• DNA replication allows genetic information to be passed to new/daughter cells.
• DNA replication is semi-conservative, as new DNA consists of one new strand and one old/parent strand.
• DNA Helicase unzips the DNA.
• DNA Ligase joins the strands.

Steps in DNA Replication

• DNA replication occurs at several points called "replication fork".
• The parent DNA helix unwinds and separates into two strands.
• Nucleotides are attracted to the complementary bases.
• Complementary base pairing occurs.
• New strands join together using DNA polymerase.
• The result is two identical DNA helices, each with one original strand and one new strand.
• Semi-conservation states that 50% of the genetic information comes from the parent DNA and 50% from the daughter DNA/new strand.