1.3 How do cells move?

Question 1

Cilia and Flagella

Answer 1

• Microtubles control the beating of cillia and flagella, locomotor appendages of some cells
• Cillia and flagella differ in their beating patterns

Question 2

Motion of flagella

Answer 2

—————————————->

Direction of swimming

Question 3

Motion of Cillia

Answer 3

—————————————–>
Direction of movement

Recovery stroke

Question 4

Dynein ‘walking’ moves flagella + cillia

Answer 4

• Dynein arms alternatively grab, move, and release the outer microtubules
• Protein cross-links limit sliding
• Forces exerted by dynein arms cause doublets to curve, bending the cillium or flagellum

effects of unrestrained dynein movement:

microtubules contain the dynein protein which cross-links proteins between outer doublets

Question 5

Actin/myosin ‘walking’/motors facilitate muscle cell contractions

Answer 5

Muscle cell

1. actin filament
2. myosin filament
3. myosin head

Question 6

Amoeboid movement

Answer 6

1. cortex (outer cytoplasm): gel with actin network
2. Inner cytoplasm: sol with actin ubunits
3. extending pseudopodium