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BIO 110 > Cytoskeleton > Flashcards

Flashcards in Cytoskeleton Deck (29)
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1
Q

What is a Cytoskeleton?

A
  • Internal supporting structure for Eukaryotes

- Much less important in plant BUT its still present

2
Q

What is the role of a Cytoskeleton?

A

-Helps maintain the shape and mechs for changing shapes and moving in Eukaryotes

3
Q

How is the Cytoskeleton different in Plant cells?

A
  • They use cell wall & osmotic pressure from central vacuole to maintain the shape
  • They don’t move & change shape?
4
Q

What is a Cytoskeleton made up of?

A
  • Multiple types of protein fibers (any long thing, molecule, object)
  • Can also be Fibril or Filament
  • There’s 3 types of fibers
5
Q

What are the 3 types of fibers that can form a Cytoskeleton?

A
  • Microtubules
  • Microfilament (actin fiber)
  • Intermediate Filaments
6
Q

What is the structure for Microtubules?

A
  • Thickest fiber

- They’re hollow tubes made of Tubulin protein subunits

7
Q

What is Tubulin?

A
  • Protein subunits in Microtubules
  • They are a Heterodimer= which is made up of 2 different polypeptides that associate noncovalently
  • Then these Heterodimers associate noncovalently into tubule
  • Alpha & Beta associate to form microtubular subunit
8
Q

What is a Tubule?

A
  • Product of Heterodimers associating noncovalently
  • Have 2 opposite ends (plus & minus)= Polar fiber
  • Can assemble & grow at the plus end and shrink at the minus end
9
Q

What is the Function of a Microtubule?

A
  • Structural support for cell (along w/ other skeletal components)
  • Moves material within cells which makes Microtubules the highways of the cell
  • Plays important role in cell movement bc these microtubules are major components of Cilia & Flagella
10
Q

How is the Microtubule railroad track used?

A
  • Vesicles follow this railroad track w/ the AID of motor proteins which “walks” the vesicles along
  • It forms spindles that moves chromosomes when cells divide during mitosis & meiosis
11
Q

What is the structure of a Microfilament?

A
  • It’s the thinnest one out the the (3) fibers
  • Long thin fibers of Actin protein subunits
  • Its 2 helical strands of actin wrapped around eachother by noncovalent association
12
Q

What is the function of a Microfilament?

A
  • Structural support by forming Stress Fibers (bundles of microfilament)
  • These stress fibers are at points of attachment to surfaces & other cells= Focal Adhesions
  • Plays role in cell movement & shape changes
  • Major participant in muscle contraction in specialized muscle cells
13
Q

How does Microfilament help in Muscle Contraction?

A

-Myosin Filaments (thicker filaments) move closer to Actin Filaments (thinner filaments)

14
Q

What are Intermmediate Filaments?

A
  • They are an intermmediate thickness
  • More of a class of several types of proteins= Kertain, Lamin (in lamina, Vimentin but they all assemble in a similar way
15
Q

What is the structure of Intermmediate Filaments?

A
  • They Line up end to end & then are twisted into a cable
  • BUT they’re not hollow like the microtubule
16
Q

What is the Function of Intermmediate Filaments

A
  • Shape & Structural support but are MORE STATIC COMPONENT to the cytoskeleton
  • Forms nuclear lamina (protein network immediately inside nuclear envelope)
  • INTERMEDIATE FILAMENTS HAVE NO ROLE IN MOTION/ MOVEMENT
17
Q

What do all 3 fibers have in common?

A

-They form a network associated w/ membrane & organelles

18
Q

What are Microtubules associated with?

A

-Mitochondria & ER

19
Q

What are Intermediate Filaments associated with?*

A

-IT ACTUALLY has little correlation to organelles bc Intermediate Filaments are PURELY STRUCTURAL

20
Q

What is the Actin Filament associated with?

A

-Membrane

21
Q

What do Tubule & Actin filaments have in common?

A
  • They pervate the ENTIRE cytoplasm along w/ associated organelles
  • They are constanly assembling & dissasembling
22
Q

Why is change in the Cytoskeleton a good thing?

A

-It allows changes in shape & movement

23
Q

How is change in the Cytoskeleton occur?

A
  • When Actin filaments move against eachother in muscle & other cells
  • Microtubules shorten, lengthen, & completely rearrange for cell division
  • Some cells will move using Cilia & Flagella (same structure but may have different lengths & motion)
24
Q

How do Microtubules change for cell division?

A
  • They will shorten, lengthen, & completely rearrange themselves
  • The old structures diassemble & spindles form for chromosome to separate during mitosis
25
Q

What is the structure of Cilia & Flagella?

A
  • 2 Pairs of inner Microtubules are surrounded by 9 Pairs of the outer Microtubules= 9+2 structure
  • Protein Dynein is inside the structure= moves cilia & flagella
26
Q

What is the distinct movement of Flagella?

A
  • Its a rotary whip-like motion

- This motion is used in sperm & Kinetoplastid Trypanosome

27
Q

What is the distinct movement of Cilia?

A
  • Wave-like motion

- Used in cililate Paramecium

28
Q

What do other cells use to generate motion & change shape?

A
  • Microfilaments

- Amoeba moves via amoeboid movement= sends pseudopods out & drags the amoeba

29
Q

What are the fibers from thickest to thinnest?

A
  • Microfilaments
  • Intermediate filaments
  • Actin filaments