Lecture 3: Cytoskeleton

Question 1

Organelle responsible for recycling in cell?

Answer 1

Lysosome

Question 2

Organelle responsible for Detox in cell?

Answer 2

Peroxisome

Question 3

Peroxisomes are found in every cell but are most prominent in the ______ and _____

Answer 3

Peroxisomes are found in every cell but are most prominent in the kidney and liver

Question 4

Vesicles that bud off of the Golgi apparatus contain ______ that then travel to other organelles or to the plasma membrane of the cell where they excrete their contents out into the cell exterior

Answer 4

Vesicles that bud off of the Golgi apparatus contain PROTEINS that then travel to other organelles or to the plasma membrane of the cell where they excrete their contents out into the cell exterior

Question 5

Components of Cytoskeleton?

Answer 5

Microfilaments (Actin)

Intermediate Filaments

Microtubules (Tubulin)

Question 6

Microfilaments

5-7 nM diameter

Found in all cells _________ cell membrane

Actin ______ and ______ to allow cell to change shape

_______ subunit assmebles into filaments

Answer 6

Microfilaments

5-7 nM diameter

Found in all cells BENEATH cell membrane

Actin Polymerises and Depolymerisess to allow cell to change shape

G ACTIN subunit assembles into filaments

Question 7

__________ polymerization/depolymerizatin is key to facilitating Phagocytosis

Answer 7

ACTIN (Microfilament)

Question 8

Microvilli contain ______ providing a structural framework but also allow the microvilli to shorten and elongate

Answer 8

ACTIN

Question 9

Proteins glycosylated are always on ________ surface

Answer 9

Proteins glycolyated are always on extracellular surface

Question 10

______ and ______ are involved with the sliding of actin and myosin fi,aments as part of muscle contraction

Answer 10

ATP and Ca2+ are involved with the sliding of actin and myosin fi,aments as part of muscle contraction

Question 11

_______ are involved with the division of cytoplasm to form two daughter cells during cytokinesis

Answer 11

MICROFILAMENTS

Question 12

________ are involved with cell motility and microvilli support

Answer 12

Microfilaments

Question 13

_________ are involved with forming pertuberances

Answer 13

Microfilaments

Question 14

Composed of 2 globular proteins, alpha and beta-tubulin, which can be readily assembled and disassembled to accommodate changes in cell shape.

Answer 14

Microtubules

Question 15

Microtubules originate from a specialized microtubule organising centre (MTOC) called the _____.

Answer 15

Microtubules originate from a specialized microtubule organising centre (MTOC) called the CENTROSOME

Question 16

The centrosome is composed of a pair of _________, filaments of microtubules that accumulate at the MTOC

Answer 16

Centrioles

Question 17

___________ regulates the formation and elongation of microtubules

Answer 17

Centrosome regulates the formation and elongation of microtubules

Question 18

___________ are the railway system of the cell

Answer 18

Microtubules

Question 19

______\_ moves along the growing ends of the microtubule towards the cell centre (+ or – ?)

Answer 19

Dynein moves along the growing ends of the microtubule towards the cell centre (Negative)

Question 20

_________ moves along the growing ends of the microtubule away from the cell centre (+ or – ?)

Answer 20

Kinesins move along the growing ends of the microtubule away from the cell centre (Positive)

Question 21

Colchicine:

• Binds tubulin and blocks ___________
• Results in ________ of microtubules

Answer 21

Colchicine:

• Binds tubulin and blocks Polymerizationn
• Results in Breakdown of microtubules

Question 22

Taxol

• Forces tubulin into stable MT’s
• Inhibits formation of _________

Answer 22

Taxol

• Forces tubulin into stable MT’s
• Inhibits formation of mitotic spindle

Question 23

Vinblastine

• _________ formed MT’s
• Forces tubulin crystalisation

Answer 23

Vinblastine

• De-polymerises formed MT’s
• Forces tubulin crystalisation

Question 24

Cilia and Flagella share a common ultrastructure composed of a core of ________ surrounded by a membrane

Answer 24

Cilia and Flagella share a common ultrastructure composed of a core of MICROTUBULES surrounded by a membrane

Question 25

Structure of Cilia:

• The central core consists of ____ microtubules
  
  • Central pair surrounded by ___ doublets
• Cilia movement results from bending of doublets by _______ catalyzed reaction

Answer 25

Structure of Cilia:

• The central core consists of 20 microtubules
  
  • Central pair surrounded by NINE doublets
• Cilia movement results from bending of doublets by DYNEIN catalyzed reaction

Question 26

Cilial Dyskinesia Primary versus Secondary

Answer 26

Primary

– Autosomally recessive genetic defect in cilia motor proteins

– Respiratory problems, ectopic pregnancy, male infertility

Secondary

– Due to inflammation/injury of tissue

– Smoking

Question 27

The function of Intermediate Filaments?

Answer 27

Provide great tensile strength to cells

ie. In epithelial cells when stretched

Question 28

Keratins, Neurofilaments, Vimentin and Nuclear Lamins are all examples of _______

Answer 28

Intermediate Filaments

Question 29

____________: A genetic disease involving mutations in the gene encoding for cytokeratins 5 and 15, resulting in a lack of cohesion between epithelial cells and underlying basement membrane causing blistering and fluid loss

Answer 29

Epidermolysis Bullosa Simplex

Question 30

Cytoskeleton Overview:

_________: Rail Network / Motor Cargo

__________: Motility / contraction

___________: Structure / Shape / Cell-Cell Junctions

Answer 30

Cytoskeleton Overview:

Microtubules: Rail Network / Motor Cargo

Microfilaments: Motility / contraction

Intermediate Filaments: Structure / Shape / Cell-Cell Junctions