Chapter 6 (pt 2) Flashcards
What is the basic definition of a cytoskeleton?
a cytoskeleton is a network(chain) of fibers in the cytoplasm
what is the purpose of a cytoskeleton in the cytosol?
It provides shape
support
guides transport vesicles to diff. parts of cells
what are the main types of fibers that make up a cytoskeleton?
There are three:
2. 1. Microtubules
2. Intermediate filaments
3. Microfilaments
How does the microtubule look like? explain their molecular structure
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
what’s the main function of a microtubule?
To give cell **support and shape **
They are the main structure used for **intracellular transportation **
What’s the structure of microfilaments like? describe their molecular structure
they are the thinnest fibers out of all three,
it’s made up of two protein strands called actinin a **double helical **shape
What are the functions of microfilaments?
it aids in cell shape and support
it aids in cell structural change
it aids in cell division
What’s the structure of intermediate filaments like? What are they composed of?
they are multiple different proteins wrapped into an intermediate shaped coil
How does the cytoskeleton provide transportation for the cell?
They act as a monorail guide where motor proteins attach and move along the fiber carrying the vesicles
How do motor proteins move along the cytoskeleton? (what process aids them in moving?)
They use ATP to move across cells while carrying vesicles
What is the place where all microtubules gather together in cell?
Centrosome
What is another nickname of centrosomes?
Microtubule organizing center
Where do microtubules actually originate from?
They originate from two centrioles where each is made up of 9 sets of 3 microtubules (one set = 3 microtubules)
What’s the relationship between centrosomes and centrioles?
The pair of centrioles are contained INSIDE of the centrosome’s region
What are cilia and flagella?
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.
Are cilia and flagella different? how?
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
Describe the structure of cilia and flagella
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
what’s the relationship between the proteins - myosin and actin
The myosin pulls on the actin filaments in order to work together for these functions:
- In microfilaments that function in cell motility, they pair up
- In muscle cells, they pair up to help with muscle contraction
- In amoeba and white blood cells, they aid movements
- In the cytoplasm, they **circulate flow of the fluid to help distribute materials in cells **
Are there materials that reside/exist outside the cells it anatomically? What are they called?
Yes, they are called extracellular structures
What are some examples of extracellular structures?C
Cell Walls
Extracellular matrix
Intercellular junctions
What are structure / function of cell walls?
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)
Extracellular Matrix exists in which type of cells (plants/animal)
Animal cells
What is the structure of ECM?
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
What is the function of ECM?
They help cells stick together,
they regulare cell’s environment,
they aid in transport
How do cells perform communication with other cells?
Through intercellular junctions
How many major types of intracellular junctions exist
Four different types:
1.Plasmodesmata
2.Tight Junctions
3.Desmosomes
4.Gap Junctions
where does plasmodesmata occur and how does it faciliate transport?
It occurs in plants ONLY, they faciliate transport from cell to cell by creating a pore for materials to travel through
Where does gap junctioning occur and how is transport faciliated?
It occurs ONLY in animal cells and transport is faciliated through pores
How are plant cells and animal cells held together in order to transport materials?
Through both tight junctions and desmosomes
