Chromosomes and DNA

Flashcards covering key terms and concepts from the chapter on chromosomes and DNA.

Chromosomes

Thread-like structures found in the nucleus of eukaryotic cells that contain genetic information.

Karyotype

The particular array of chromosomes that an individual possesses.

Chromatid

One half of two identical copies of a duplicated chromosome, joined by a centromere.

Centromere

The region of a chromosome where the two sister chromatids are joined.

Telocentric

A type of chromosome where the centromere is located at the end.

Acrocentric

A type of chromosome where the centromere is near one end.

Submetacentric

A type of chromosome where the centromere is off-center, creating two arms of unequal length.

Metacentric

A type of chromosome where the centromere is located in the middle, creating two equal-length arms.

Nucleosome

A structural unit of DNA consisting of a segment of DNA wrapped around a core of histone proteins.

Euchromatin

Less condensed chromatin that is associated with active gene expression.

Heterochromatin

Highly condensed chromatin that is generally not expressed.

Gene

A segment of DNA that encodes information for protein synthesis.

DNA replication

The process by which DNA makes a copy of itself before cell division.

Semi-conservative replication

A method of DNA replication in which each of the two daughter DNA molecules contains one original and one newly-synthesized strand.

Mutation

A change in the DNA sequence that may lead to changes in function and phenotype.

Point mutation

A mutation affecting only a single nucleotide in the DNA sequence.

Central dogma

The flow of genetic information from DNA to RNA to protein.

Transcription

The process in which a complementary RNA strand is synthesized from a DNA template.

Translation

The process by which mRNA is decoded and a polypeptide chain is produced.

Codon

A sequence of three nucleotides in mRNA that codes for a specific amino acid.

tRNA

Transfer RNA; a type of RNA that helps assemble amino acids into proteins.

rRNA

Ribosomal RNA; a type of RNA that is a structural component of ribosomes.

Mutagen

An agent that causes changes to the genetic material, resulting in mutations.

Chromosomal aberration

A change to the structure or number of chromosomes leading to genetic disorders.

The one-gene/one-enzyme hypothesis

The idea that each gene encodes the information for a specific enzyme.