genome organisation Flashcards
(7 cards)
genomes:
prokaryotes: bacteria/archaea, simplest structure, most basic life form, no nucleolus.
eukaryotes- more complicated, bigger, organelles present, animal/plants/fungi.
prokaryote genomes:
circular genome- one or many, occasionally linear.
supercoiling- positive or negative due to addition of extra turn in double helix or removal of turn.
packed in nucleoid- anchored with protanine.
genome is compact with little or no extra DNA. plasmids can transfer from 1 bacterium to another. confer antibiotic resistance/ability to use complex compounds as food.
eukaryote genomes:
wide range- unicellular and multicellular.
gene- sequence of DNA or RNA that codes for a molecule (protein) that has a function. intron- non coding sections of the DNA.
exon- coding section of the DNA.
pseudogene- gene sequence with no transcription.
genome wide repeat- repeated throughout genome.
retrotransposon- short interspersed nuclear element, long interspersed nuclear element, long terminal repeats.
transposon- DNA that can move around genome.
tandem repeat- repeated immediately.
genomic DNA (gDNA):
linear chromosomes. most have 2 copies of each chromosome- diploid but some (fungi mainly) haploid. 1 set of chromosomes from each parent.
packaging of chromosomes:
linear chromosomes are bound to charged protein complex. termed histone protein.
22 autosomal pairs+ XX/XY. karyotype. inherited in mendelian fashion.
mitochondrial DNA:
small, circular DNA- 16.5kn. located in the mitochondria. high copy number per cell. genes for mitochondrial function and tRNA/rRNA.
mtDNA- faster mutation rate than nuclear DNA. low variation due to uni parental inheritance. useful in species identification.
chloroplast DNA:
nearly all code around 200 genes. much larger than mtDNA- pea 120kb. rRNA, tRNA, photosynthesis genes and ribosomal proteins. high copy number.
cpDNA- low variation due to uni parental inheritance (in most instances), useful in species identification.
