CHAPTER 10

Question 0

cytoskeleton function

Answer 0

help maintain cell shape

Question 1

what is the cytoskeleton composed of?

Answer 1

microtubules, micro filaments, intermediate filaments

Question 2

microtubules

Answer 2

• hollow polymers of tubulin dimers
• make up spindle apparatus
• negative end (dyenin) grows slower and positive end (kinesin) grows faster
• go through dynamic instability
• large diameter
• organized into centrisomes

Question 3

microfilaments

Answer 3

• polymers of actin monomers
• small diameter
• helical
• highly dynamic
• responsible for cellular contractions
• reinforce plasma membrane
• branched in cell cortex
• contractile ring structure
• cytosol streaming
• myosin

Question 4

intermediate filaments

Answer 4

• permanent structure
• medium diameter
• structure for nucleus
• mechanical strength
• when cell dies, they remain
• very strong
• protein monomer non specific
• attach to cytoplasmic side of desmosomes

Question 5

cilia and flagella

Answer 5

• made up of microtubules
• requires ATP
• stretches plasma membrane
• flagella 9+2 dynen

Question 6

cell adhesion

Answer 6

allow cells to attach to other cells and to extracellular matrix proteins

Question 7

cadherins

Answer 7

transmembrane proteins that allow cells to adhere to other cells

Question 8

integrins

Answer 8

transmembrane proteins that facilitate cell adhesion to the extracellular matrix

Question 9

adherens junction

Answer 9

• use cadherins
• there are many cadherins but only bond to the same type (e cadherins with e and n cadherins with n)
• cadherins are anchored to microfilaments
• embedded in plasma membrane

Question 10

desmosomes

Answer 10

• cadherins anchored to intermediate filaments
• only connect to other cells
• provide secure attachment

Question 11

tight junctions

Answer 11

• tight junction protein
• seals and transports
• prevents passage of substance through space between cell
• divide plasma membrane into apical and basolateral regions

Question 12

gap junctions

Answer 12

• ring like protein chamber in each cell
• plasmodesmata in plants
• allow passage of substance from cytoplasm of one cell to other
• gap junction channel proteins

Question 13

hemidesmosomes

Answer 13

• intermediate filaments
• integrin proteins
• located in basal lamina (part of ECM)
• anchor cell and ECM

Question 14

cell migration

Answer 14

• cells follow cone gradient of a nutrient to its source
• actin polymerization of microfilaments
• cell surface receptors cause movements toward nutrients
• leading edge reaches out and trailing end contracts

Question 15

extra cellular matrix

Answer 15

-plants
>found in cell wall
>made up of polysaccharides cellulose and lignan

-animals
>found in abundance of connective tissue
>made up of collagen (very strong)
>triple helix