34. cilia and flagella 33. cytocenter centrioles

Question 1

What is cilia

Answer 1

short, membrane extensions, highly motile (larger than microvilli)

Question 2

What is flagella

Answer 2

lobg singular membrane extension
provides locamotion but sensory organelle
only in spermatazoa in humans

Question 3

What is the core structure of cilia and flagella

Answer 3

The basal bodies (kinetosome) provided by centrioles

9 peripheral microtubules, 2 central microtubules

cross section looks like ring

CALLED THE AXONEME

Question 4

types of cilia

Answer 4

kinocilia
sensocilia
sterocilia

Question 5

structure of kinocilia

Answer 5

typical cilia

motile, abundant in epithelial cells (columnar/cuboidal)

length: 5-10um diameter: 0.2 um

3 parts:
AXONEME: 9 peripheral doublets of microtubules ( A+B )
2 central singlets surrounded by inner sheath
= 9x2+2

TRANSITORY: between axoneme and basal body

BASAL BODY: microtubule organization centre (kinetosome)
9 peripheral triplet of microtubukes (A,B,C)
no microtubules in center
= 9x3+0

Question 6

structure of sensocilia

Answer 6

non motile, speacialized cells of sense organs. enriched with receptors to detect light, oddor, sound

AXONEME (central core): 9 peripheral doublets
no singlets in centre
9x2+0

Question 7

stereocilia

Answer 7

much longer than kinocilia but non motile

resembles microvilii

observed in epididymis or hair cells of inner ear

Question 8

flagella

Answer 8

length: 100-200um

1 flagellum per cell

only in spermatozoa in humans

Question 9

What is Kartageners syndrome

Answer 9

defect in cilia lining respiratory tract and fallopian tube
bc thers no dyenin arms

Question 10

how does cilia and flagella move

Answer 10

bc of axoneme and axonemal dynein arms attached to the microtubules

Question 11

what is another name for the cell center

Answer 11

centrosome

Question 12

who first observed cell center

Answer 12

oscar hertwig 1875

Question 13

What are the functions of centrioles

Answer 13

aid cell division: form mitotic spindle as part of cytokinesis
formation of cilia and flagella on surface of cells and building of basal bodies of cytoskeleton

Question 14

What is the structure of centrioles

Answer 14

9 triplets: 9x3 + 0 of microtubules (which are themselves made of a+b tublin)
centrin, cenexin tektin
barrel structure
diameter: 0.15-0.2um

Question 15

what does the position of the centrioles determine

Answer 15

the position of the nucleus

Question 16

Which organelle serves as the main microtubule organizing center (MTOC)

Answer 16

centrosome

Question 17

Does everyone have centrosomes

Answer 17

no fungi and plants dont- they are not essential/ may have other MTOCs

Question 18

What is the centrosome composed of

Answer 18

centrioles arranged in right angles surrounded by pericentriolar material (protein)

the proteins are responsible for microtubule nucleation and anchoring

Question 19

which part of the cell cycle is centrosomes associated with th nuclear envelope

Answer 19

prophase

Question 20

when nuclear membrane breaks down in mitosis, centrosome can interact with chromosomes to build what

Answer 20

mitotic spindle

Question 21

when do centrioles replicate

Answer 21

S phase of cell cycle