Motility

For bacteria to get the nutrients to [blank_start]grow[blank_end], they must sometimes [blank_start]move[blank_end] towards them.

The scientific word for this movement is [blank_start]motility[blank_end]. Bacteria are motile because of tail-like structures on their surface called [blank_start]flagella[blank_end].

Label the points marked on the image below.

Scientists have done lots of experiments to prove that motility is essential for Campylobacter to cause [blank_start]disease[blank_end]. By [blank_start]deleting[blank_end] the piece of DNA which codes for the [blank_start]flagella[blank_end], we can see that the bacteria are worse at colonising the [blank_start]gut[blank_end]. Bacteria that cannot colonise the gut cannot cause disease.

Chemotaxis is the movement of cells in response to [blank_start]chemical[blank_end] signals. These signals can attract cells (chemoattractants) or repel them (chemorepellents). Campylobacter randomly change direction occasionally. The cells will move further down a [blank_start]chemotactic[blank_end] gradient, than up one. This means, cells will gradually move towards a [blank_start]favourable[blank_end] environment in the presence of chemotactic signals, and will continually move [blank_start]randomly[blank_end] without them.