BIOL 200- Vocabulary (Final)
30-nm Fibres: The 30nm fiber is the DNA in its interphase state. The DNA is wrapped
around the histone complex and then is twisted into a solenoid structure,
the 30 nm fiber.
Acetylation: The histones are acetylated and deacetylated on lysine residues in the N-
terminal tail and on the surface of the nucleosome core as part of gene
regulation. Acetylation removes the positive charge on the histones,
thereby decreasing the interaction of the N termini of histones with the
negatively charged phosphate groups of DNA. As a consequence, the
condensed chromatin is transformed into a more relaxed structure that is
associated with greater levels of gene transcription.
Antisens: Antisense DNA is the non-coding strand complementary to the coding
strand in double-stranded DNA. The antisense strand serves as the
template for messenger RNA (mRNA) synthesis.
Centromeres; A centromere is a region on a chromosome that joins two sister
Chromatid: Either of the two daughter strands of a replicated chromosome that are
joined by a single centromere and separate during cell division to become
Chromosome: Microscopic rod-shaped structures that appear in a cell nucleus
during cell division, consisting of nucleoprotein arranged into units
(genes) that are responsible for the transmission of hereditary
Construct: A DNA construct is an artificially constructed segment of
nucleic acid that is going to be "transplanted" into a target tissue or
cell. It often contains a DNA insert, which contains the gene
sequence encoding a protein of interest, that has been subcloned
into a vector, which contains bacterial resistance genes for growth in
bacteria, and promoters for expression in the organism.
DNA fingerprinting: A technique for comparing the nucleotide sequences of fragments of DNA
from different sources. The fragments are obtained by treating the DNA
with various endonucleases, enzymes that break DNA strands at specific sites.; A method used to identify multilocus DNA banding patterns that are
specific to an individual by exposing a sample of the person's DNA to
molecular probes and various analytical techniques such as Southern blot
DNA Transposons: A small mobile genetic (DNA) element that moves around the genome or to
other genomes within the same cell, usually by copying itself to a second
site but sometimes by splicing itself out of its original site and inserting in a
new location. Eukaryotic transposons are sometimes called transposable
Euchromatin: Chromosomal material that consists of uncoiled dispersed threads during
interphase, is genetically active, and stains lightly with basic dyes.
Gene Families: A gene family is a set of several similar genes, formed by duplication of a
single original gene, and generally with similar biochemical functions.
Genes are categorized into families based on shared nucleotide or protein
Gene: A segment of DNA, occupying a specific place on a chromosome, that is the
basic unit of heredity. Genes act by directing the production of RNA, which
determines the synthesis of proteins that make up living matter and are the
catalysts of all cellular processes.
Genome: A genome is the entirety of an organism's hereditary information. It is
encoded either in DNA or, for many types of virus, in RNA. The genome
includes both the genes and the non-coding sequences of the DNA/RNA.
Helicase: An enzyme involved in DNA replication, responsible for unwinding the
Heterochromatin: The part of the chromonema that remains tightly coiled and condensed
during interphase and thus stains readily.
Heterozygotes; The genes for a specific trait are different.
Histone: In biology, histones are highly alkaline proteins found in eukaryotic cell
nuclei, which package and order the DNA into structural units called
nucleosomes. They are the chief protein components of chromatin, act as
spools around which DNA winds, and play a role in gene regulation.
Homozygote; An organism with identical pairs of genes (or alleles) for a specific trait. If both of the two gametes (sex cells) that fuse during fertilization carry the
same form of the gene for a specific trait, the organism is said to be
homozygous for that trait.
In Situ Hybridization: Molecular hybridization used to analyze prepared cells or histologic
sections in situ in order to analyze the intracellular or intrachromosomal
distribution, transcription, or other characteristics of specific nucleic acids.