Cell Division and Molecular Biology - Part 1: The Structure of DNA

Vocabulary flashcards covering the key terms, molecular components, and organizational structures of DNA based on Biology 30 lecture notes.

Deoxyribonucleic Acid (DNA)

A molecule found in all living things responsible for the continuity of life, which is passed from parent to child and located in the nucleus, mitochondria, and chloroplasts.

Chromosomes

Large segments of DNA found in the nucleus; human cells contain 23 pairs (a total of 46 chromosomes), with 23 from the egg and 23 from the sperm.

Gene

A small segment of a chromosome that contains the code to build one particular protein molecule.

Human Genome Gene Count

Approximately 20 000 genes, where an individual carries 2 copies of each gene (one inherited from the egg and one from the sperm).

Nucleotide

The building block of DNA, composed of deoxyribose (a 5-carbon sugar), a phosphate group ($PO_4^{3-}$), and one of four nitrogen bases.

Deoxyribose

A 5-carbon sugar found in nucleotides that alternates and stacks with phosphates to form the sides of the DNA ladder.

Phosphate ($PO_4^{3-}$)

A chemical component of a nucleotide that, together with deoxyribose, forms the outer sides (backbone) of the DNA ladder.

Antiparallel

The orientation of the two sides of the DNA ladder, where one strand begins with a phosphate and the other begins with deoxyribose.

Hydrogen Bonds

Chemical bonds that connect pairs of nitrogen bases together to form the rungs of the DNA ladder.

Purines

Larger double-ring nitrogen base molecules found in DNA, specifically adenine (A) and guanine (G).

Pyrimidines

Smaller single-ring nitrogen base molecules found in DNA, specifically cytosine (C) and thymine (T).

Complementary Base Pairing

The specific pairing rules in DNA where adenine (A) only pairs with thymine (T), and cytosine (C) only pairs with guanine (G).

Double Helix

The spiral shape formed when the two long strands of nucleotides twist together.