Gene and genome organisation of bacteria and viruses Flashcards
The definition of a genome That genomes can consist of DNA or RNA, linear or circular molecules, and single or multiple units (chromosomes) Differences in the size and packaging of genomes in bacteria, viruses and eukaryotes Aspects of the sequence organization of genes in bacteria and ‘phages The occurrence of additional genetic elements in bacterial cells
What is the definition of genome?
The entire genetic content of an organism
What can the genome of an organism be? (3)
Single or double stranded DNA or RNA
Linear or circular
Contained in single or multiple units
What is the definition of a chromosome?
The physical location of the genes
Where can the genomes in eukaryotic cells be found? (3)
Nucleus
Mitochondria
Chloroplasts
What do most bacteria have regarding chromosomes?
A single chromosome
Why are genes arranged into chromosomes?
Provides a convenient parcel of DNA that can cue duplicated and partitioned
How many origins of replication do chromosomes have?
At least one
What is the molecular material of a chromosome?
Incredibly complex pure nucleic acids
Several levels of chromatin
What is the cellular structure of a chromosome?
DNA/protein complex
What are the 3 factors in gene organisation?
Gene density around the circular chromosome
Operons
Overlapping genes
What do genes in bacteria and phages often form?
Polycistronic operas (2 or more genes transcribed from the same promoter)
What are the components of an idealised operon? (3)
Activator binding site
Promoter
Repressor binding site (operator)
What is an example of genetic efficiency?
Overlapping genes in bacteriophages - multiple genes are made
