Genome - the complete genetic composition of a cell or a species
Proteome – complete complement of proteins that a cell or organism can make
C value – the total amount of DNA per haploid cell
C value paradox - We would expect that the more complex the organism, the more DNA is needed to “run it”
Therefore, we would expect a linear relationship between genome size and organism complexity.
At the lower range of complexity, this holds: Bacteria have smaller genomes than eukaryotes, and viruses have smaller genomes than bacteria.
In larger organisms, relationship breaks down - Organisms have DNA apparently in excess of what is needed; repetitive sequences, “junk DNA”. This is the C value Paradox, that in the most complex organisms, there doesn’t appear to be the expected relationship between complexity and genome size.
Melting temperature (Tm) - is the temperature at which 50% of a double-stranded nucleic acid (usually DNA, but also RNA or any hybrid combination) is denatured.
Melt temperature varies with base composition. For instance, a greater GC content typically increases Tm because more hydrogen bonds need disrupting in GC base-pairs (3 compared to 2 in AT pairs).
Chromosome – A discrete unit of genetic material composed of DNA and associated proteins
Eukaryotes have chromosomes in their cell nuclei and plasmids and mitochondria
Centromere – region where 2 sister chromatids are tightly associated; the centromere is an specialised attachment site for kinetochore proteins
Telomere – region at the ends of eukaryotic chromosomes where a specialised form of DNA replication occurs.
Gene – unit of heredity that contributes to the characteristics or traits of an organism. At the molecular level a gene is composed of organised sequences of DNA
Intron – intervening DNA sequences that are fund in-between the coding sequences of DNA
Exon – A portion of RNA that is found in the mature mRNA molecule after slicing is finished
Histones – group of proteins that aid in the compaction of eukaryotic cells
Nucleosomes – structural unit of eukaryotic chromosomes composed of octamer of histones (8 histone proteins) wrapped with DNA
Chromatin – refers to biochemical composition of chromosomes, which contain DNA and many types of protein
Condensation reaction – chemical reaction in which 2 or more molecules are combined into one large molecule by covalent bonding, with the loss of a small molecule.
Epigenetic inheritance – an inheritance