Question

Construct a table to summarize the four major types of biochemical reactions studied in this course. For each type give the name, a word summary of what happens during the reaction, and an example of where the reaction might be biologically important.

Answer 1

Reaction type | Word summary (what happens) | Example (where biologically important)
--- | ---: | ---
Oxidation–reduction (oxidoreductases) | Electrons (and often H) are transferred between molecules; one substrate is oxidized and the other reduced. | Mitochondrial electron-transport chain: NADH is oxidized and O2 is reduced to H2O to generate a proton gradient for ATP synthesis.
Group transfer (transferases) | A functional group (e.g., phosphate, acetyl, glycosyl) is transferred from one molecule to another. | Glycolysis: hexokinase transfers a phosphate from ATP to glucose (glucose → glucose‑6‑phosphate); protein kinases regulate signaling by phosphorylating proteins.
Hydrolysis (hydrolases) | A bond is broken by addition of water; large molecules are cleaved into smaller ones. | Proteolysis by digestive proteases or lysosomal proteases (peptide bond hydrolysis); ATP hydrolysis by myosin drives muscle contraction.
Ligation/condensation (ligases/synthetases) | Two molecules are joined (often forming a new C–C, C–N, or C–S bond) with input of energy (usually ATP). | DNA ligase joins Okazaki fragments during DNA replication; aminoacyl‑tRNA synthetases attach amino acids to tRNAs (ATP-dependent).