DNA & Chromosomes: High-Yield Study Guide

Vocabulary flashcards covering key terms related to DNA and chromosomes, useful for exam preparation.

Nucleotide

Basic building block of DNA, consisting of deoxyribose sugar, a phosphate group, and a nitrogenous base.

Purines

Nitrogenous bases with a double-ring structure; includes Adenine (A) and Guanine (G).

Pyrimidines

Nitrogenous bases with a single-ring structure; includes Cytosine (C) and Thymine (T).

Phosphodiester bond

Covalent bond linking nucleotides together by connecting the 5' phosphate group of one nucleotide to the 3' –OH of another.

Antiparallel strands

Refers to the orientation of the two strands of DNA, where one runs 5’ to 3’ and the other 3’ to 5’.

Base pairing rules

Rules for complementary base pairing in DNA: A pairs with T (2 hydrogen bonds), and C pairs with G (3 hydrogen bonds).

Genome

The complete set of DNA, including all of its genes, in an organism.

Gene

A segment of DNA that encodes a functional product, which can be a protein or functional RNA.

Chromatids

Identical halves of a replicated chromosome, joined at the centromere.

Telomeres

Repeated DNA sequences at the ends of chromosomes, protecting them from degradation.

Centromere

Constricted region of a chromosome that links sister chromatids and attaches to mitotic spindle.

Chromatin

Complex of DNA and proteins (mainly histones) that condenses to form chromosomes.

Nucleosome

Basic structural unit of chromatin, consisting of DNA wrapped around a histone octamer.

Euchromatin

Less condensed form of chromatin that is transcriptionally active and gene-rich.

Heterochromatin

Tightly packed form of chromatin that is transcriptionally inactive and gene-poor.

Histone acetylation

Modification of histones by adding acetyl groups, which generally increases gene expression.

Transcription factors (TFs)

Proteins that bind to DNA to regulate gene expression; can be activators or repressors.

Restriction enzymes

Proteins that cut DNA at specific sequences, used in cloning and DNA analysis.

Gel electrophoresis

Technique for separating DNA fragments by size using an electric field.

PCR (Polymerase Chain Reaction)

Technique used to amplify DNA, involving denaturation, annealing, and extension.