Genome Organisation
Genome Organisation-
Universally, DNA contains purines (adenosine, guanine) and pyrimidines (cysteine, thymine, uracil (found in RNA)). These guys are the bases, in which three of it together will code for a codon, that signifies an amino acid. A sequence of these codons assist with making up a peptide chain. As you know, peptides together, after having been rearranged into a 3D structure is a protein.
As you can see in the picture, DNA’s backbone is connected by phosphodiester bonds (I can get into this later and why its called what its called). These bonds help create the phosphate backbone of DNA. Since phosphate groups (PO4–) are negatively charged, a chunk of PO4–used as the backbone of the DNA will make the DNA a highly negative molecule.
As you already know, DNA is a double helix. The two strands are antiparallel. Basically, DNA strands are replicated from what is called the 5′ (five prime) end to the 3′ end (I’ll break it down in another post).
5′——-TAG———>3′
3′<—–ATC———–5′
The bases (T, A, G, C) are connected to each other by weak hydrogen bonds.
Organization of DNA in ProkaryotesDNA are supercoiled, and require ATP and an enzyme topoisomerase to uncoil the DNA.
In prokaryotes, DNA are shown in plasmids and nucleoid.
Prokaryote cell replicates by binary fission.
PlasmidsBacterial chromosomal DNA with plasmid DNA
Bacteria contains a chromosomal DNA as well as a plasmid DNA, independent from the chromosomal DNA and is capable of replicating itself without chromosomal DNA. Plasmids are also found in some eukaryotes. Plasmids codes for a gene that allows it to infect the host’s immune system. The number of plasmids are unlimited in bacteria (more than thousands of its copy).
Benefit of Plasmid to Bacteria:
Protection against antibiotics
Chromosomal DNAChromosomes contain genes needed for the cell to survive.
Single copy genes – are very important and if they are damaged we would be in trouble since there is only ONE!
repetitive genes aka “junk DNA” – has unknown functionality
GenomeThe genome of an organism is basically knowing every single gene. So far, we know 100% of E. coli and thus, it is widely used in laboratories.
The human’s genome is only at about 90%. Even though our genotype is similar, our phenotype is vastly different due to limited or certain expression of certain genes.
Organization of DNA in EukaryotesDifferent than prokaryotes, in Eukaryotes:
As you can see in the picture, DNA’s backbone is connected by phosphodiester bonds (I can get into this later and why its called what its called). These bonds help create the phosphate backbone of DNA. Since phosphate groups (PO4–) are negatively charged, a chunk of PO4–used as the backbone of the DNA will make the DNA a highly negative molecule.
As you already know, DNA is a double helix. The two strands are antiparallel. Basically, DNA strands are replicated from what is called the 5′ (five prime) end to the 3′ end (I’ll break it down in another post).
5′——-TAG———>3′
3′<—–ATC———–5′
The bases (T, A, G, C) are connected to each other by weak hydrogen bonds.
Organization of DNA in ProkaryotesDNA are supercoiled, and require ATP and an enzyme topoisomerase to uncoil the DNA.
In prokaryotes, DNA are shown in plasmids and nucleoid.
Prokaryote cell replicates by binary fission.
PlasmidsBacterial chromosomal DNA with plasmid DNA
Bacteria contains a chromosomal DNA as well as a plasmid DNA, independent from the chromosomal DNA and is capable of replicating itself without chromosomal DNA. Plasmids are also found in some eukaryotes. Plasmids codes for a gene that allows it to infect the host’s immune system. The number of plasmids are unlimited in bacteria (more than thousands of its copy).
Benefit of Plasmid to Bacteria:
Protection against antibiotics
Chromosomal DNAChromosomes contain genes needed for the cell to survive.
Single copy genes – are very important and if they are damaged we would be in trouble since there is only ONE!
repetitive genes aka “junk DNA” – has unknown functionality
GenomeThe genome of an organism is basically knowing every single gene. So far, we know 100% of E. coli and thus, it is widely used in laboratories.
The human’s genome is only at about 90%. Even though our genotype is similar, our phenotype is vastly different due to limited or certain expression of certain genes.
Organization of DNA in EukaryotesDifferent than prokaryotes, in Eukaryotes:
- Nucleus – containing chromosomes or DNA that are supercoiled
- Nucleus – has histones – proteins covering DNA that allows our chromosome to condense.