Topic 6: Microbiology, immunity and ecosystems - Edexcel A-Level Biology B quiz

It is a cell with a cell wall and circular DNA

It has only a protein coat surrounding its nucleic acid

It can reproduce only inside a living host cell

It contains no genetic material whatsoever

By providing useful extra nutrients to the host cells they enter

By damaging host cells or producing toxins

By increasing the host's overall immunity to infection

By speeding up the rate of respiration in host cells

The initial lag phase

The stationary plateau phase

Exponential (log) phase

The final death phase

Viruses are simply far too large for antibiotic molecules to enter and act upon them

Antibiotics can only ever work inside the bloodstream and never within the body's own tissues

Viruses are able to produce their own protective antibiotics to defend themselves

Viruses lack the bacterial structures antibiotics target and reproduce inside host cells

Natural selection acting on random mutations

Individual bacteria consciously deciding to resist the antibiotics

The antibiotics directly creating brand new resistance genes

Bacteria gradually turning into viruses

They engulf and digest invading pathogens by phagocytosis

They secrete antibodies specific to the antigen

They form part of the physical skin barrier

They produce toxins to kill pathogens

The invading pathogen is always much weaker the second time it enters the body

Antibodies can now be made directly without any lymphocytes being involved

Memory cells from the first response recognise the antigen and divide rapidly

Phagocytes are no longer needed at all

1 per cent

50 per cent

90 per cent

10 per cent

Nutrients such as carbon and nitrogen

Energy from the original sunlight captured by producers

Heat lost through respiration

Light absorbed by plants

Using a single quadrat

Mark-release-recapture

Counting every individual once

A line transect