3.3.2 Centrioles, Flagella, and Cilia

Question 1

centriole

Answer 1

• a cylindrical structure in an animal cell. Centrioles occur in pairs and are involved in the formation of the apparatus that distributes chromosomes to the daughter
  cells during cell division
• occur in an arrangement called a “9 + 0” pattern. The term is derived from the fact that there are nine fused triplets of microtubules surrounding an empty space.

Question 2

flagella and cilia

Answer 2

• structures that aid in locomotion or move fluids across the surface of tissue cells of animals
• Flagella are relatively long structures that function as propellers in locomotion. Cilia are relatively short and work like oars.
• In cilia and flagella, a specialized arrangement of microtubules is responsible for their locomotive ability.
• Cilia and flagella have an identical 9 + 2 microtubule arrangement. There are nine fused pairs of microtubules surrounding an unfused pair of microtubules.
• Protein motor molecules attach to the outer microtubules and enable bending of the cilia or flagella.

Question 3

protein motor molecules

Answer 3

• The microtubules of both cilia and flagella have protein motor molecules that provide the force for bending and movement.

Question 4

note

Answer 4

• Using ATP as an energy source, the protein motor molecules of one microtubule grip the adjacent pair, pull, release, and then bind again. The microtubules can’t slide far past each other because they are anchored. The action of the motor molecules causes the
  microtubules to bend.

Question 5

The symptoms of an inherited genetic disorder include respiratory problems and sterility in males. What is a reasonable hypothesis for the basis of this disorder?

Answer 5

• a defect in microtubules that limits the motility of cilia and flagella

Question 6

__________ are like small oars, while __________ are more like large propellers.

Answer 6

• cilia; flagella

Question 7

True or false?

Flagella are composed of a 9 + 2 array of microtubules, whereas cilia are composed of a 6 + 3 array of microtubules.

Answer 7

• false

Question 8

Which of the following statements about cilia and flagella are not true?

a. Cilia and flagella are composed of microtubules.
b. Cilia and flagella facilitate cellular movement through beating or whipping movements.
c. Cilia and flagella are composed of actin filaments.
d. Cilia and flagella are anchored to the cell by basal bodies.

Answer 8

• c. Cilia and flagella are composed of actin filaments

Question 9

Which of the following statements about centrioles is incorrect?

a. Centrioles are not commonly found in plant cells.
b. Centrioles have a 9+0 structure.
c. Centrioles are contained within the centrosome of the cell.
d. Centrioles help organize the microtubules during cell division in all eukaryotic cells.

Answer 9

• d. Centrioles help organize the microtubules during cell division in all eukaryotic cells.

Question 10

Structures used by some organisms for locomotion include

Answer 10

• cilia and flagella