Binary fission and virus replicationAQA A-Level Biology: Flashcards

What these 13 flashcards ask

What is binary fission?
What is replicated first in binary fission?
What is a plasmid?
What does each daughter cell receive in binary fission?
Why does the number of plasmids vary between daughter cells?
How many cells after n divisions from one cell?
A bacterium divides every 30 minutes. How many cells after 3 hours from one cell?
Why do viruses not undergo cell division?
What does a virus inject into a host cell?
What replicates the virus particles?
What is a bacteriophage?
Why can't a virus replicate outside a host cell?
Name one similarity between binary fission and virus replication.

Exam questions on Binary fission and virus replication

A microbiologist inoculated a flask of sterile nutrient broth with a single Escherichia coli cell. Under these conditions each cell divides by binary fission once every 20 minutes and none of the cells die.
Explain why the daughter cells each contain exactly one copy of the circular DNA but may contain different numbers of plasmids.2 marks
A virologist is studying a bacteriophage, a virus that infects bacteria. When a phage attaches to a bacterium it injects its nucleic acid into the host cell and its protein coat stays outside.
Explain why phages cannot replicate in sterile nutrient broth that contains no bacteria.2 marks
A hospital laboratory is investigating two patients: one has a bacterial infection and the other has a viral infection.
Describe how a virus replicates after it has attached to a host cell.3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).