Question

describe the location(where can they be found), structure(wha tis it composed/made of), function(what is its job/role) of carbohydrates

Answer 1

Here’s a concise overview of carbohydrates by location, structure and function.

Location (where they can be found)
- In organisms: ubiquitous in plants, animals, fungi, bacteria and protists.
- Plants: abundant in leaves, stems, roots, seeds and fruits (starch in seeds/tubers; cellulose in cell walls; sugars in sap and fruit).
- Animals: blood and body fluids (glucose), liver and muscle (glycogen), connective tissues (glycosaminoglycans).
- Fungi and arthropods: chitin in cell walls and exoskeletons.
- Within cells/tissues:
- Cytosol: free monosaccharides (glucose) and metabolic intermediates used in glycolysis.
- Organelles: starch stored in plant plastids (amyloplasts); glycogen particles in cytosol of animal cells (liver, muscle).
- Cell surface/extracellular matrix: glycoproteins and glycolipids on membranes; structural polysaccharides in cell walls.

Structure (what they are made of)
- Basic chemistry: organic molecules of carbon, hydrogen and oxygen, commonly written (CH2O)n.
- Monomers: monosaccharides (simple sugars) — e.g., glucose, fructose, galactose (5‑ or 6‑carbon rings/forms).
- Linkage: monosaccharides join by glycosidic bonds (α- or β-linkages) to form larger carbs.
- Classes:
- Monosaccharides — single sugar units.
- Disaccharides — two monosaccharides linked (sucrose, lactose, maltose).
- Oligosaccharides — short chains (3–10 units), often on proteins/lipids for cell recognition.
- Polysaccharides — long polymers:
- Storage polysaccharides: starch (plants; amylose/amylopectin with α-1,4 and α-1,6 bonds), glycogen (animals; highly branched α-1,4/α-1,6).
- Structural polysaccharides: cellulose (plants; β-1,4 glucose chains forming fibers), chitin (β-1,4 N-acetylglucosamine).
- Modifications: sugars can be phosphorylated (e.g., glucose-6-phosphate), aminated (glucosamine), or attached to proteins/lipids (glycosylation).

Function (what they do)
- Energy source: glucose is the primary fuel for cells; monosaccharides enter glycolysis to produce ATP.
- Energy storage: starch (plants) and glycogen (animals) store glucose for later use.
- Structural support: cellulose in plant cell walls; chitin in fungal cell walls and arthropod exoskeletons; glycosaminoglycans in connective tissue.
- Cell recognition and signaling: oligosaccharides on glycoproteins/glycolipids mediate cell–cell recognition, immune responses and receptor binding.
- Metabolic intermediates: building blocks for nucleotides (ribose/deoxyribose) and components in biosynthetic pathways.
- Dietary fiber: nondigestible polysaccharides (cellulose, some hemicelluloses) aid digestion and gut health.

Summary
Carbohydrates are carbon‑, hydrogen‑ and oxygen‑based biomolecules found throughout living systems; structurally they range from simple monosaccharides to complex polysaccharides linked by glycosidic bonds, and they serve as fuels, storage molecules, structural materials and mediators of cellular recognition and signaling.