What are the four main types of biological molecule, and what does each do in a living thing?
Describe the basic molecular structures and primary functions of the four major categories of biological macromolecules: carbohydrates, lipids, proteins, and nucleic acids (NGSSS SC.912.L.18.1; Reporting Category 1, Molecular and Cellular Biology).
A benchmark-level answer on biological macromolecules for the Florida Biology 1 EOC: carbohydrates, lipids, proteins, and nucleic acids, their monomers, the elements they contain, and the function of each.
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What this topic is asking
The NGSSS benchmark SC.912.L.18.1 asks you to describe the basic structures and primary functions of the four major macromolecules: carbohydrates, lipids, proteins, and nucleic acids. For the Florida Biology 1 EOC you need to know each one's monomer (building block), the elements it contains, and its function. Items usually give you a description (a monomer, an element ratio, or a function) and ask you to name the macromolecule.
The big idea: monomers and polymers
Knowing the monomer is the fastest way to identify a macromolecule on the EOC, so learn the four monomer-to-macromolecule pairs.
Carbohydrates
- Monomer: monosaccharide (a simple sugar such as glucose).
- Elements: carbon, hydrogen, and oxygen (roughly a 1:2:1 ratio).
- Function: the main source of quick energy. Includes sugars (glucose, sucrose) and larger storage and structural forms (starch in plants, glycogen in animals, cellulose in plant cell walls).
When an EOC item mentions sugars, starches, or quick energy, the answer is carbohydrate.
Lipids
- Building blocks: fatty acids and glycerol (lipids are not built from a single repeating monomer the way the others are).
- Elements: mostly carbon and hydrogen (with little oxygen), which is why they are nonpolar and do not dissolve in water.
- Function: long-term energy storage, insulation, and forming the phospholipid bilayer of cell membranes. Includes fats, oils, waxes, and steroids.
A clue for lipids is "does not dissolve in water" (hydrophobic), or a role in the membrane or long-term energy storage.
Proteins
The amino-acid monomer and the link to enzymes are the most-tested protein facts.
Nucleic acids
- Monomer: nucleotide (a sugar, a phosphate, and a base).
- Elements: carbon, hydrogen, oxygen, nitrogen, and phosphorus.
- Function: store and carry genetic information. The two types are DNA (the genetic code) and RNA (which helps build proteins).
Nucleic acids connect this topic to DNA structure and protein synthesis.
Try this
Q1. Name the monomer of proteins and one function of proteins. [2]
- Cue. The monomer is the amino acid; proteins build structures, act as enzymes, transport substances, or defend the body (any one).
Q2. State which two macromolecules contain nitrogen, and name the monomer of each. [2]
- Cue. Proteins (monomer: amino acid) and nucleic acids (monomer: nucleotide) both contain nitrogen.
Exam-style practice questions
Practice questions written in the style of FLDOE exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
FL Biology 1 EOC (2023 released style)1 marksWhich macromolecule is the body's main source of quick energy and includes sugars and starches? (A) Protein. (B) Lipid. (C) Carbohydrate. (D) Nucleic acid.Show worked answer →
A 1-point multiple-choice item matching a macromolecule to its function.
The correct answer is C. Carbohydrates (sugars and starches) are the body's main quick-energy source; their monomer is the monosaccharide (such as glucose). Proteins build and do work, lipids store energy long-term and form membranes, and nucleic acids carry genetic information.
Match the macromolecule to its monomer and main job; quick energy plus sugars and starches equals carbohydrate.
FL Biology 1 EOC (2024 released style)1 marksA molecule is made of amino acids linked in a chain and folds into a specific shape that lets it act as an enzyme. Which macromolecule is it? (A) Carbohydrate. (B) Lipid. (C) Protein. (D) Nucleic acid.Show worked answer →
A 1-point item using the monomer to identify the macromolecule.
The correct answer is C. Proteins are built from amino acids and fold into specific shapes; enzymes are proteins. The monomer (amino acid) is the giveaway. Carbohydrates are built from sugars, lipids from fatty acids and glycerol, and nucleic acids from nucleotides.
Related dot points
- Explain the role of enzymes as catalysts that lower the activation energy of biochemical reactions, and identify factors such as pH and temperature that affect enzyme activity (NGSSS SC.912.L.18.11; Reporting Category 1, Molecular and Cellular Biology).
A benchmark-level answer on enzymes for the Florida Biology 1 EOC: catalysts and activation energy, the active site and substrate, the lock-and-key model, and how temperature, pH, and denaturation affect enzyme activity.
- Discuss the properties of water that contribute to Earth's suitability as an environment for life (NGSSS SC.912.L.18.12; Reporting Category 1, Molecular and Cellular Biology).
A benchmark-level answer on water for the Florida Biology 1 EOC: polarity and hydrogen bonding, cohesion and adhesion, high heat capacity, the universal solvent, and why ice floats.
- Describe the structure of DNA and the basic process of DNA replication, and how it relates to the transmission and conservation of genetic information (NGSSS SC.912.L.16.3; Reporting Category 1, Molecular and Cellular Biology).
A benchmark-level answer on DNA for the Florida Biology 1 EOC: the double helix and nucleotide structure, complementary base pairing, semiconservative replication, and why copying conserves genetic information.
- Identify the reactants, products, and basic functions of photosynthesis (NGSSS SC.912.L.18.7; Reporting Category 1, Molecular and Cellular Biology).
A benchmark-level answer on photosynthesis for the Florida Biology 1 EOC: the reactants and products, the chloroplast and chlorophyll, where the energy goes, and the overall equation.
- Identify the reactants, products, and basic functions of aerobic and anaerobic cellular respiration (NGSSS SC.912.L.18.8; Reporting Category 1, Molecular and Cellular Biology).
A benchmark-level answer on cellular respiration for the Florida Biology 1 EOC: the reactants and products of aerobic respiration, the role of the mitochondrion and ATP, and the two types of anaerobic respiration (fermentation).
Sources & how we know this
- Next Generation Sunshine State Standards: Science (Biology 1) — Florida Department of Education (2024)
- Biology 1 End-of-Course Assessment Test Item Specifications — Florida Department of Education (2024)