Nuclear chemistry & biochemistry · Topic 15 of 15

Organic Chemistry & Biochemistry Basics

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Chemistry · organic & biochemistry

Organic Chemistry & Biochemistry Basics

Carbon's four bonds build chains and rings; functional groups set behavior; dehydration synthesis builds polymers, hydrolysis splits them, and enzymes are proteins.

01 · Why carbonCarbon makes 4 bonds

02 · Build vs breakBuild: lose H₂O · split: add H₂O

03 · EnzymesEnzymes are proteins

What it is

Organic = carbon-based molecules (C with H, often O or N) must know

Hydrocarbon = only carbon and hydrogen (methane CH₄ is simplest) must know

Enzymes are proteins (amino-acid chains) that speed cell reactions must know

Functional group = atom cluster that sets a molecule's behavior

Monomer = one building block; polymer = a long chain of them

Peptide bonds link amino acids; their order sets the protein's shape

Heat or pH change denatures an enzyme: shape lost, function lost

Parts & jobs

Hydroxyl –OH → alcohol (not a base, unlike NaOH)

Carboxyl –COOH → carboxylic acid (a weak acid)

Amino –NH₂ → amine (a weak base)

Sugars → carbohydrates · amino acids → proteins · nucleotides → DNA/RNA

Lipids: not true polymers (fat = glycerol + 3 fatty acids)

The rules

Carbon forms 4 bonds → chains, branches and rings must know

Worked examples

3 glucose → C₁₈H₃₂O₁₆ + 2 H₂O (n monomers release n − 1 waters)

Don't confuse

Dehydration synthesis releases H₂O to build; hydrolysis adds H₂O to split must know

Alkane: single bonds (saturated) · alkene: C=C · alkyne: C≡C

Dehydration synthesis or hydrolysis?

Commonly confused

	Dehydration synthesis	Hydrolysis
What it does	Joins monomers into a polymer	Splits a polymer into monomers
Water	Released at each new bond	Added at each broken bond
Everyday case	Linking amino acids into a protein	Digesting food

Common mistakes

Trap: hydro + lysis = water-splitting (breaks); dehydration builds

More detail

Show 5 more facts

Endings: -ane single, -ene double, -yne triple bond

meth 1 · eth 2 · prop 3 · but 4 · pent 5 … dec 10 carbons

Alkanes (not rings): CₙH₂ₙ₊₂ — propane C₃H₈

Carbonyl C=O → aldehydes (C=O with an H) and ketones

Isomers: same formula, different structure (butane, isobutane)

Pearl

Building a polymer gives off a water; breaking one takes a water back.

Sources · OpenStax Chemistry 2e §20.1 Hydrocarbons · OpenStax Chemistry 2e §20.2 Alcohols and Ethers · OpenStax Chemistry 2e §20.3 Aldehydes, Ketones, Carboxylic Acids, and Esters · OpenStax Chemistry 2e §20.4 Amines and Amides · OpenStax Biology 2e §3.1 Synthesis of Biological Macromolecules · OpenStax Biology 2e §3.4 Proteins · TSTC Libraries — HESI A2 guide: Chemistry content list (enzymes as proteins; bonds in common hydrocarbons) · Union Test Prep — HESI Chemistry study guide, page 4 (biochemistry) · Built from the verified NurseSavvy HESI A2 fact map (facts reviewed 2026-10-16). HESI is a trademark of Elsevier; NurseSavvy is not affiliated with Elsevier.

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