Chapter 6 (pt 2)

Question 1

What is the basic definition of a cytoskeleton?

Answer 1

a cytoskeleton is a network(chain) of fibers in the cytoplasm

Question 2

what is the purpose of a cytoskeleton in the cytosol?

Answer 2

It provides shape
support
guides transport vesicles to diff. parts of cells

Question 3

what are the main types of fibers that make up a cytoskeleton?

Answer 3

There are three:
2. 1. Microtubules
2. Intermediate filaments
3. Microfilaments

Question 4

How does the microtubule look like? explain their molecular structure

Answer 4

It’s the** thickest fiber **out of all three, they are made up of two proteins, **alpha and beta tubulin **

their shape resembles a tube and it’s hollow from inside

Question 5

what’s the main function of a microtubule?

Answer 5

To give cell **support and shape **
They are the main structure used for **intracellular transportation **

Question 6

What’s the structure of microfilaments like? describe their molecular structure

Answer 6

they are the thinnest fibers out of all three,
it’s made up of two protein strands called actinin a **double helical **shape

Question 7

What are the functions of microfilaments?

Answer 7

it aids in cell shape and support
it aids in cell structural change
it aids in cell division

Question 8

What’s the structure of intermediate filaments like? What are they composed of?

Answer 8

they are multiple different proteins wrapped into an intermediate shaped coil

Question 9

How does the cytoskeleton provide transportation for the cell?

Answer 9

They act as a monorail guide where motor proteins attach and move along the fiber carrying the vesicles

Question 10

How do motor proteins move along the cytoskeleton? (what process aids them in moving?)

Answer 10

They use ATP to move across cells while carrying vesicles

Question 11

What is the place where all microtubules gather together in cell?

Answer 11

Centrosome

Question 12

What is another nickname of centrosomes?

Answer 12

Microtubule organizing center

Question 13

Where do microtubules actually originate from?

Answer 13

They originate from two centrioles where each is made up of 9 sets of 3 microtubules (one set = 3 microtubules)

Question 14

What’s the relationship between centrosomes and centrioles?

Answer 14

The pair of centrioles are contained INSIDE of the centrosome’s region

Question 15

What are cilia and flagella?

Answer 15

They are both locomoter appendages (physical components that help in movement of a body) made up of a system of microtubules

locomoter appendages = fins / tails etc.

Question 16

Are cilia and flagella different? how?

Answer 16

They have a different moving pattern: Cilia moves with rythmic strokes in one direction
but flagella moves more fluidly like a snake to create motion

Question 17

Describe the structure of cilia and flagella

Answer 17

Both contain microtubules which are encased within a plasma membrane, it also is anchored onto a body that it’s supposed to be moving,
they also contain the motor protein, dyein, that aids in movement

Question 18

what’s the relationship between the proteins - myosin and actin

Answer 18

The myosin pulls on the actin filaments in order to work together for these functions:

1. In microfilaments that function in cell motility, they pair up
2. In muscle cells, they pair up to help with muscle contraction
3. In amoeba and white blood cells, they aid movements
4. In the cytoplasm, they **circulate flow of the fluid to help distribute materials in cells **

Question 19

Are there materials that reside/exist outside the cells it anatomically? What are they called?

Answer 19

Yes, they are called extracellular structures

Question 20

What are some examples of extracellular structures?C

Answer 20

Cell Walls
Extracellular matrix
Intercellular junctions

Question 21

What are structure / function of cell walls?

Answer 21

Function: they maintain shape and provide security from enviroment, also prevent excessive water intake

Structure: they are made up of cellulose (cellulose fibers) + few carbohydrates and proteins (for transportation)

Question 22

Extracellular Matrix exists in which type of cells (plants/animal)

Answer 22

Animal cells

Question 23

What is the structure of ECM?

Answer 23

they are made up of glycoproteins, such as collagen, proteoglycans and fibronectin

To communicate with the insides of cell, the proteins bind to the receptor protein sites on plasma membrane called intergrins

Question 24

What is the function of ECM?

Answer 24

They help cells stick together,
they regulare cell’s environment,
they aid in transport

Question 25

How do cells perform communication with other cells?

Answer 25

Through intercellular junctions

Question 26

How many major types of intracellular junctions exist

Answer 26

Four different types:
1.Plasmodesmata
2.Tight Junctions
3.Desmosomes
4.Gap Junctions

Question 27

where does plasmodesmata occur and how does it faciliate transport?

Answer 27

It occurs in plants ONLY, they faciliate transport from cell to cell by creating a pore for materials to travel through

Question 28

Where does gap junctioning occur and how is transport faciliated?

Answer 28

It occurs ONLY in animal cells and transport is faciliated through pores

Question 29

How are plant cells and animal cells held together in order to transport materials?

Answer 29

Through both tight junctions and desmosomes