Cell systems - cytoskeleton (copy)

What is inside a cell?

Nucleus - DNA

Mitochondria - ATP

Golgi/ER - make membrane and secreted proteins

Lysosomes - protease filled

Vesicles - move molecules between compartments

What kind of membrane do cells have?

Lipid membrane - defines their shape

What makes bacteria cells different?

They have a rigid cell wall - made of polysaccharide cross-linked with peptides

What is the cytoskeleton made of?

Protein polymers

What are the types of cytoskeletons?

Intermediate filaments

Actin filaments

Microtubules

Describe intermediate filaments - how they form

1. proteins elongated

2. Dimers are formed head to head to form coil structure

3. Tetramers (dimers attached together) form into rope like filaments - very strong

What are intermediate filaments function?

rope like bundles supporting the cell. strong and stable. protein supports keratin

what is Epidermolysis bullosa simplex

disease caused by defect in keratin, results in blisters forming between cell sheets

what is junctional epidermolysis bullosa

affects animals, in horses known as red foot disease.

signs of junctional epidermolysis bullosa

blistering of gingiva and tongue in nursing. blistering of skin and hooves shedding

Describe actin filaments (cytoskeleton)

long, thin protein strands. Always changing and allow cell to change shape and move.

What is the actin cytoskeleton's function?

Phagocytosis, cell migration and cytokinesis (cell division)

Also sits underneath there plasma membrane, gives strength

Describe microtubules

- grow from centre of cell

- gives cell ability to move things around

- connected to organelles through motor proteins

Why are microtubules polarised

so the cell know which end is which. allow cell to know whether things are moving in or out.

How do microtubules aid in mitosis?

At the beginning of cell division, the microtubules depolymerise

1. Building the mitotic spindle: helps pull apart the chromosomes.

2. Guiding Chromosomes: connect to the chromosomes, act like ropes and help move them to the right places in the dividing cell.

3. Pulling Apart Chromosomes

4. Organising Cell Division: Microtubules also help determine where the cell will divide, each new cell is even.

Why do animal cells have a cytoskeleton rather than a cell wall

In order to change shape