The first growth phase of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.
Scanning electron microscope (SEM)
A microscope that uses an electron beam to scan the surface of a sample to study details of its topography.
The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.
A breeding experiment in which parental varieties differing in two characters are mated (e.g. seed colour and seed shape).
A population of genetically identical cells. For example those containing identical recombinant DNA molecules.
The period in the cell cycle when the cell is not dividing. During interphase, cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase. Interphase accounts for 90% of the cell cycle.
Ribosomal RNA (rRNA)
The most abundant type of RNA, which together with proteins, forms the structure of ribosomes. Ribosomes coordinate the sequential coupling of tRNA molecules to mRNA codons.
(plural, nucleoli) A specialized structure in the nucleus, formed from various chromosomes and active in the synthesis of ribosomes.
Alternative RNA splicing
A type of regulation at the RNA-processing level in which different mRNA molecules are produced from the same primary transcript depending on which RNA segments are treated as exons and which as introns.
A membranous sac in a mature plant cell with diverse roles in reproduction, growth, and development.