Cilia, Flagella, and Mitosis

Question 1

Cilia:

Answer 1

Move material across the surface of cells.
9+2 Cilium structure:
- 9 microtubule doublets in a circle.
- 2 microtubule singlets in the centre.
- Spokes binds the singlets to the doublets and the spokes limit movement.
-If the spokes are removed, dynein causes sliding of microtubules relative to one another.

Question 2

Flagella:

Answer 2

Propel Cells through liquid e.g. sperm.
Move through a beating process:
-Power Stroke
-Recovery Stroke

In normal flagellum: Dynein causes bending of microtubule doublets that are connected by linker proteins.

Question 3

Intraflagellar transport:

Answer 3

Bidirectional motility that is essential for the formation and maintenance of most eukaryotic cilia and flagella.
Involves movement of large protein complexes called IFT particles (or trains) from the cell body to the ciliary/flageullar tip and followed by their return to the cell body.

Question 4

The Centrosome is Duplicated During Mitosis.

TRUE OR FALSE

Answer 4

TRUE

They duplicate and move to opposite poles.

Question 5

Microtubule dynamics are static during mitosis.

TRUE OR FALSE

Answer 5

FALSE
Microtubule dynamics are enhanced during mitosis:
Interphase: t1/2 = 5 Minutes
Metaphase: t1/2 = 15 Seconds

Question 6

Equal tension must be applied to each side of the kinetochore before chromatid separation can proceed.
TRUE OR FALSE

Answer 6

TRUE

2 forces determine this tension: Push and Pull

Question 7

Push and Pull forces determine tension applied to each side of the kinetochore before chromatid separation can proceed: What determines the push and pull forces?

Answer 7

Pull = Pulling force is proportional to the length of the kinetochore microtubules.
Push = Astral exclusion force decreases with distance from the pole.

Question 8

Organelle Inheritance:

Answer 8

Organelles segregate along cytoskeletal filaments to ensure both daughter cells Inherit all the organelles they need.
Some organelles first split by fission.

Question 9

Cytokinesis Contractile Ring is made from?

Answer 9

Actin Filaments.

Cytokinesis is driven by actin based myosin contraction.

Question 10

The kinetochore maintains attachment to the microtubules whilst allowing for both microtubule growth and shrinkage.
TRUE OR FALSE

Answer 10

TRUE