how are the monomers of glucose assembled and disassembled into starch and sugars?

Glucose monomers are joined into starch by dehydration synthesis (condensation reactions that form glycosidic bonds and release water) and broken back into sugars by hydrolysis (adding water to break those bonds, usually with enzymes like amylase).

Big idea in simple terms

Think of glucose molecules as individual beads and starch as a long beaded necklace.
Building the necklace (starch) means snapping beads together and releasing tiny “clips” of water, and cutting the necklace back into beads (sugars) means adding water back at each snap point to separate them.

Assembling glucose into starch (building)

This process is called dehydration synthesis or condensation reaction.

1. Start with glucose monomers
   • Glucose is a monosaccharide (single sugar unit) and the basic building block of starch.

 * In plants, many glucose units are linked together to form the polysaccharide starch.

2. Form glycosidic bonds by removing water
   • When two glucose molecules join, an −OH-OH−OH (hydroxyl) group from one and an −H-H−H (hydrogen) from the other are removed to form a water molecule H2O\text{H}_2\text{O}H2​O.

 * The remaining oxygen links the two glucoses through a **glycosidic bond** , often an α-1,4-glycosidic bond in starch.

 * Example step: glucose + glucose → maltose + water (and similar steps repeat to build long chains).

3. Repeat to make long chains and branches
   • Repeating condensation reactions adds more glucose units, creating long chains (amylose) and branched chains (amylopectin) that together make starch.

 * Enzymes like **starch synthases** use activated glucose (ADP-glucose) to extend these chains and build starch in plant cells.

Disassembling starch into sugars (breaking)

Breaking starch back into smaller sugars uses hydrolysis.

1. Add water to break glycosidic bonds
   • Hydrolysis is the reverse of dehydration synthesis: water is added across the glycosidic bond.

 * The bond splits so that one glucose gets an −OH-OH−OH and the other gets an −H-H−H, restoring their original hydroxyl groups.

2. Enzymes speed this up
   • Enzymes such as amylase attack starch chains at specific points and cut them into smaller sugars like maltose and eventually glucose.

 * In living organisms, these enzyme-catalyzed hydrolysis reactions allow starch to be converted into usable energy-rich glucose.

3. Stepwise breakdown
   • Starch is first broken into shorter chains called dextrins, then into disaccharides (like maltose) and finally into glucose monomers.

 * Each step is a hydrolysis reaction that uses one water molecule per bond broken.

Quick forum-style recap

Glucose units link up into starch by dehydration synthesis : every time two glucose molecules join, they form a glycosidic bond and release water.

To get back sugars, starch undergoes hydrolysis : enzymes add water across those glycosidic bonds, breaking the chain back into smaller sugars and eventually free glucose.

TL;DR:
Glucose monomers are assembled into starch by condensation (dehydration) reactions that create glycosidic bonds and release water, and they are disassembled back into sugars by enzyme-driven hydrolysis reactions that use water to break those bonds.

Information gathered from public forums or data available on the internet and portrayed here.