Glossary
chromatin:
Chromatin is a structure consisting of DNA and histones.
It is the primary constituent of a chromosome.
deoxyribonucleic acid (DNA):
A
double-stranded chain of nucleotides. It carries a
cell’s genetic information and is found in the cells of
all living organisms. It is capable of self replication
and the synthesis of RNA.
enzyme:
cellular
proteins that
catalyze
chemical reactions.
Almost all enzymes are
proteins.
Almost all processes in cells need enzymes in order to
occur at significant rates. Enzyme activity can be
affected by other molecules.
Inhibitors
are molecules that decrease enzyme activity;
activators
are molecules that increase activity.
epigenetics:
The
study of inherited characteristics that lie outside of
the genome in organisms (from the word epi,
meaning “outside” or “above,” originally from the
Greek).
epigenome:
the comprehensive biological unit that controls gene
function and expression, comprised of DNA and the
histone proteins.
gene:
A
region on the chromosome that is the basic unit of
inheritance and
is a union of genomic sequences encoding a coherent set
of potentially overlapping functional products.
genetics:
Genetics is the study of DNA-based inherited
characteristics in organisms.
genome:
the entire hereditary information of an organism,
includes both the
genes and
the
non-coding sequences
of the DNA. The term was coined in 1920 by
Hans Winkler,
Professor of
Botany at
the
University of
Hamburg,
Germany,
as a
portmanteau
of the words gene and chromosome.
histone:
are
the chief
protein
components of
chromatin.
They act as the spools around which
DNA
winds, and they play a role in
gene regulation.
nucleosome:
The
fundamental unit of chromatin. It is composed of two
copies of each of the four core histones, around which
146 base pairs of DNA are wrapped.
nucleotide:
A
chemical compound consisting of a sugar, one phosphate
group, and one of four nitrogenous bases: adenine,
cytosine, guanine, and thymine.
post translational histone modification:
the chemical modification of chromatin through
methylation, acetylation, phosphorylation and
ubiquitination that
controls the tightness of the DNA around the histone
proteins and, consequently, controls the expression of
the genes.
translation:
The
process by which a complete messenger RNA molecule
serves as a template for the biosynthesis of a specific
protein.
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