2.1.5- Other Features Of Eukaryotic Cells Flashcards
What are ribosomes made of?
Ribosomal RNA.
Where are ribosomes made?
Nucleolus.
Explain how ribosomes are made.
They’re made in the nucleolus as two separate subunits and pass through the nuclear envelope to the cell cytoplasm which is where they combine.
After ribosomes are made, what are the two places they can go to within the cell?
They can either remain free in the cytoplasm or attach to the rough endoplasmic reticulum (RER).
In eukaryotes, ribosomes are _______ and _______ organelles.
small and spherical.
In eukaryotic cells, what size are the ribosomes?
About 20nm in diameter.
What is the function of ribosomes that are bound to the exterior of the rough endoplasmic reticulum?
They synthesise proteins that will be exported out of the cell.
What’s the function of ribosomes free in the cell cytoplasm?
They assemble proteins that will be used inside the cell.
What are the two ways ribosomes free in the cell cytoplasm can exist?
Singular or in clusters of ribosomes.
What are the four non membrane bound organelles that are going in a eukaryotic cell?
Ribosomes
centrioles
Cytoskeleton
Cellulose cell wall
Explain what the structure of centrioles is.
They consist of two bundles of microtubules at right angles to each other. The microtubules are made of tubulin protein subunits that are arranged to form a cylinder.
The microtubules in centrioles and the cytoskeleton are made of…
Tubulin subunits.
What are the two main functions of centrioles?
- involved in cell division.
* involved in the formation of cilia and undulipodia.
Explain how centrioles are involved in cell division.
Before cell division, the spindle (made of tubulin threads) forms from centrioles and chromosomes attach to the middle part of the spindle and motor proteins walk along the tubulin threads to pull the chromosomes to opposite ends of the cell.
Explain how centrioles are involved in the formation of cilia and undulipodia.
Before the cilia form, the centrioles line up and multiple underneath the cell surface membrane. The microtubules sprout outwards from each centrioles to form a cillium or undulipodium.
In what type of plants are centrioles found or not found?
They’re usually absent from cells of higher plants- but are present in some unicellular green algae- e.g; Chlamydomonas.
Where is the plant cell wall located in relation to the plasma membrane?
It is usually on the outside of the plasma membrane.
The plant cell wall is made from bundles of ______ fibres.
Cellulose.
The cellulose cell wall is strong and can help cells from doing what when they’re turgid.
Bursting.
Fungi that have cell walls have walls that are made of _______ and not cellulose.
Chitin.
List the four main functions of the cellulose cell wall in plant cells.
- maintain cell shape
- provide strength and support
- contribute to the strength and support of the whole plant
- are permeable and allow solutions (solute and solvent) to pass through
What are the four main things the cytoskeleton consists of?
Micro filaments
Intermediate filaments
Microtubules
Cytoskeletal motor proteins
The rod like microfilaments in the cytoskeleton are made of what?
Subunits of the protein actin.
The microfilaments in the cytoskeleton are __________ of the protein actin.
Polymers.
How large is each of the microfilaments present in the cytoskeleton?
Each microfilament is about 7nm in diameter.
The intermediate filaments present in the cytoskeleton are ______ in diameter about.
10nm- intermediate filaments.
The microtubules in the cytoskeleton are ________ and _________.
Straight and cylindrical.
What size are the microtubules present in the cytoskeleton on average?
18-30nm in diameter.
What are the three types of cytoskeletal motor proteins?
Mysoins
Kinesins
Dyneins
The cytoskeleton motor proteins are described as __________ _________.
Molecular motors.
As well as being molecular motors, explain what else the cytoskeletal motor proteins do.
They are also enzymes that have a site that binds to and allies the hydrolysis of ATP as their energy source.
What are the three functions of the protein microfilaments within the cytoplasm.
- give support and mechanical strength.
- keep the cells shape stable.
- allow cell movement.
What are the two main functions of the microtubules that are present in the cytoskeleton?
- provide shape and support to cells
* help substances and organelles to move through the cytoplasm within a cell
Describe three ways in which the cytoskeletal microtubules can help substances and organelles to move within the cell through the cell cytoplasm.
- they make up the cilia and undulipodia
- form a spindle before a cell divides that allow chromosomes to be moved within the cell
- form the train along which motor proteins walk and drag organelles from one part of the cell to another.
Explain all of the functions of the intermediate functions that are present in the cytoskeleton.
- anchor the nucleus within the cytoplasm.
- extend between cells in come tissues, between special junctions to enable cell- cell signalling and allowing cells to adhere to the basement membrane to stabilise the tissues.
_________ calls do my have a cellulose cell wall
Animal
Explain how motor proteins get energy that is vital for them to use inside the cell.
They have a site that binds to and allows the hydrolysis of ATP as their energy source.
