A large, transparent, thick-walled cell found in the filaments of certain blue-green algae and in certain fungi.
- ‘Nitrification cannot occur in the presence of oxygen, so nitrogen is fixed in specialized cells called heterocysts.’
- ‘These heterocysts develop from vegetative cells in a regular pattern along the filament.’
- ‘During growth the number of vegetative cells is increased by cell division and the space between heterocysts becomes larger.’
- ‘In the case of fixed nitrogen deprivation the bacteria will produce heterocysts at regular intervals, usually around ten cells apart, along the filament.’
- ‘In the 1970s, purified heterocysts from this strain were used to demonstrate that they are the sites of aerobic nitrogen fixation.’
We take a look at several popular, though confusing, punctuation marks.