Prokaryotic and extra-chromosomal genetics

Question 1

How do prokaryotes compartmentalise their DNA?

Answer 1

Nucleoid: prokaryotic DNA chromosome blob
Also plasmids
The chromosomes are usually circular and densely populated by genes
Their chromosomes are small in comparison to eukaryotes chromosomes
Haploid cells

Question 2

What cell cycle do prokaryotes use?

Answer 2

Binary fission

Question 3

What can binary fission be used to create?

Answer 3

Aggregates of cells
Many species form biofilms on surfaces or cell clumps
The cells can differentiate for specific functions

Question 4

What processes allow prokaryotes to segregate, assort and share genes and alleles of genes?

Answer 4

Conjugation
Transposition
Transduction
Transformation

Question 5

What genetic info do prokaryotic plasmids often carry?

Answer 5

1. Sequences that function to allow replication and segregation of plasmid in host cell division
2. Useful extra genes
3. Genes allowing plasmid to transfer to new cell

Question 6

Where do bacterial chromosomes replicate from?

Answer 6

A set origin of replication (oriC)

Question 7

What do bacterial replication forks do?

Answer 7

Bacterial replication forks progress in opposite directions to replicate the circular chromosome

Question 8

What is oriP?

Answer 8

Plasmids origin sequence that recruits host cell replication enzymes

Question 9

Give an example of an extra gene type that would be encoded on the plasmid.

Answer 9

Antibiotic resistance

Question 10

What is conjugation?

Answer 10

Bacterial form pili that adhere to other bacteria to form a channel to pass on genetic info (plasmids)

Question 11

What is oriT?

Answer 11

Origin of transfer

Recognition site of tra gene encoded enzymes that nick and peel off a single strand of plasmid DNA