Ch. 5 Structure of DNA and Chromosomes

These flashcards cover key vocabulary and concepts related to the structure of DNA, gene expression, and chromosomes, aiding in exam preparation.

Deoxyribonucleic Acid (DNA)

A double-stranded polynucleotide made of two separate chains of covalently linked deoxyribonucleotides, serving as the genetic information of a cell.

Double Helix

The typical structure of a DNA molecule where two complementary strands are wound around each other with base-pairing between strands.

Base Pair

Two complementary nucleotides in RNA or DNA held together by hydrogen bonds.

Genetic Code

The set of rules by which the information in nucleic acid sequences is translated into amino acid sequences of proteins.

Gene Expression

The process through which a gene makes a product that is useful to the cell by directing the synthesis of a protein or RNA.

Chromosome

A long thread-like structure made of DNA and proteins that carries the genetic information of an organism.

Karyotype

An ordered display of the full set of chromosomes of a cell, arranged with respect to size and number.

Gene

A unit of heredity that contains instructions dictating the characteristics or phenotype of an organism.

Genome

The total genetic information carried by all chromosomes of a cell or organism.

Telomere

A repetitive nucleotide sequence that caps the ends of linear chromosomes, shortening with each round of replication.

Centromere

A specialized DNA sequence that allows duplicated chromosomes to be separated during the M phase.

Histone

A small, highly conserved protein around which DNA wraps to form nucleosomes, the fundamental units of chromatin packing.

Nucleosome

The structural unit of a eukaryotic chromosome composed of a short length of DNA wrapped around an octameric core of histone proteins.

Chromatin

A complex of DNA and proteins that make up chromosomes in eukaryotic cells, existing in two main forms: heterochromatin and euchromatin.

Euchromatin

Less condensed chromatin that is prevalent in gene-rich areas and allows access for proteins involved in transcription.

Heterochromatin

Highly condensed, transcriptionally inactive regions of an interphase chromosome that are generally gene-poor.

Epigenetic Inheritance

The transmission of heritable patterns of gene expression that do not involve altering the nucleotide sequence of DNA.

Chromatin Remodeling Complex

A family of enzymes that use ATP hydrolysis energy to alter the arrangement of nucleosomes, changing DNA accessibility.

Phosphodiester Bond

The covalent bond linking the phosphate group of one nucleotide to the sugar of the next nucleotide in a DNA strand.

DNA Replication

The process in which the DNA double helix is duplicated to produce two identical copies.

Cell Cycle

An orderly sequence of events in which a cell duplicates its content and divides, including phases such as interphase and M phase.

Mitosis

A phase of the cell cycle during which the duplicated chromosomes are separated into two daughter cells.

Interphase

The phase of the cell cycle when the cell is not dividing but is preparing for mitosis, during which DNA is replicated and chromatin is less condensed.