Binary Fission and Viral Replication Flashcards
What type of cell does binary fission occur in?
Prokaryotic cells.
Give 4 differences between prokaryotes and eukaryotes.
Prokaryotes do not contain:
A nucleus
Chromosomes
Membrane bound organelles
Spindle fibres
Describe the genetic material in prokaryotes.
Single circular DNA molecule.
Plasmids, which are small loops of DNA.
What happens to the large loop of DNA in binary fission?
It’s replicated.
Describe replication of plasmids.
Describe how plasmids are received after division.
They are replicated to produce a variable number.
The number of plasmids in each cell after division varies, but is regulated.
Describe how the cytoplasm divides.
The cytoplasm roughly halves between the 2 daughter cells.
Describe the overall cell produced at the end of binary fission.
The two daughter cells each contain a single copy of the circular DNA molecule and a variable number of plasmids
What will happen if one of the daughter cells does not receive a copy of the circular DNA or any plasmids?
It will die.
Why are viruses not considered living?
They require the machinery of a host cell in order for them to replicate.
How do viruses bind to a host cell?
The attachment proteins on the virus are complimentary to the receptor proteins on the host, so they attach.
What happens to the genetic material contained in the virus during replication?
It’s injected into the host cell.
What organelle does the host cell use to build new viral particles?
Using its ribosomes?
How does the host cell release viral particles?
Give 2 ways.
The host cell eventually bursts open to release the viral particles.
Viral particles bud off the host cell membrane, taking a section of the lipid membrane with them, forming the lipid envelope in viruses.
How does the exiting of host cells cause disease? Use the example of HIV.
The HIV particles destroy helper T cells, leading to damage to the immune system.
