Cells, DNA, and Chromosomes
Where genetic information lives
Cells as the unit of life
Cells are the smallest units of life. Inside many cells, genetic information is stored in DNA. In eukaryotic organisms, most DNA is found in the nucleus.
DNA basics
DNA stands for deoxyribonucleic acid. It is a long molecule that stores instructions using a four-letter chemical code: , , , and .
A useful analogy
You can think of DNA as a cookbook, genes as specific recipes, and chromosomes as the volumes that organize those recipes.
Important structures
DNA, genes, and chromosomes
| Term | What it is |
|---|---|
| DNA | The information-carrying molecule |
| Gene | A functional segment of DNA |
| Chromosome | A package that holds DNA |
What are the four DNA letters?
DNA uses the bases adenine, thymine, cytosine, and guanine.
Correct answer: A, T, C, G
What is a chromosome?
Chromosomes organize DNA so it can be stored and managed in the cell.
Correct answer: A tightly packed structure made of DNA and proteins
In eukaryotic cells, most DNA is found in the:
The nucleus contains most of the DNA in eukaryotic cells.
Correct answer: Nucleus