Cell Structure Flashcards
What is the cytoskeleton?
A network of fibres that extend throughout the cytoplasm
Is the cytoskeleton dynamic?
Yes!
Eukaryotic cytoskeletons are composed of?
- Microtubules
- Microfilaments
- Intermediate fibres
What do motor proteins do?
Move organelles and vesicles throughout the cell on microtubule highways
What are the roles of the cytoskeleton?
- Structural support- maintains cell shape
- Movement- allows cells to change location and rearrange cell contents
What are microtubules?
Hollow protein tubes made of tubulin
What do microtubules do?
Highways for vesicle transport and cell division
What provides movement for the microtubules?
Flagella and cilia
How do microtubules grow?
By adding tubulin dimers
What are centrioles?
Nine sets of triplet microtubules arranged in a ring
Flagella and cilia are organized into?
Doublets (a 9+2 pattern)
Flagella and cilia are anchored in the cell by?
A basal body (9+0 pattern)
How do the large motor proteins move?
They walk across the microtubule using ATP for energy
What is needed go bend the flagella and cilia?
Large motor proteins
Large motor proteins are made up of?
Dyneins
What is the function of actin? (RMAC)
- Resist tension
- Muscle contractions
- Amoeboid movement
- Cystolic streaming in plant cells
What are intermediate filaments?
Medium-thickness fibres only found in animal cells
What are intermediate-filaments composed of?
Lots of proteins including keratins
What are microfilaments?
The thinnest cytoskeleton proteins
What are microfilaments made up of?
Actin
What is intermediate filaments size?
8-12nm
what are Intermediate filaments roles?
- Maintain cell shape and integrity
- Maintains organelle shape and integrity
- Make up the nuclear lamina
- Maintains organelle position within the cells
- Hair and skin are made up of keratin
Components of the ECM are made (blank) and exported (blank) via the endomembrane system
(inside the cell) (outside the cell)
What is the extracellular matrix role?
Connects cells together into tissues
What is the extracellular matrix? (ECM)
The stuff outside of the cell
What are cell walls?
Extracellular structures in plant and fungi cells
The cell wall is composed of a (blank) with a (blank) in between. Some cell walls have a (blank) between the plasma membrane and primary wall
(A primary cell wall) (middle lamella) (secondary cell wall)
What is the role of the cell wall?
Maintains cell shape, prevents the uptake of excess water
The pores of the cell wall are called?
Plasmodesmata (allows substances to travel through the cell walls)
What is the cell wall composed of?
Cellulose
Animal ECM are more complex because?
They lack a cell wall
Animal cell ECMs contain glycoproteins such as? (CPFI)
Collagen
Proteoglycans
Fibronectins
Integrins
What is the role of collagen?
Resists pulling forces
What is the role of proteoglycans?
Resists compressive forces
What is the role of fibronectins?
Connects the ECM to integrins
What is the role of integrins?
Surface receptor proteins built into the plasma membrane
What are the types of connections cells can form with one another?
Adhesion
Communication
What anchors desmosomes into the cytoplasm through the cytoskeleton?
Keratin
Adhesion of cells: what are anchoring junctions and desmosomes?
Anchoring junctions are binding proteins and desmosomes form sheets of strongly connected cells
Communication of cells: what are gap junctions?
Pipes that connects the cytosol of adjacent cells
Adhesion of cells: what are tight junctions?
Creates a seal to prevent leakage of extracellular fluid
Communication of cells: what are plasmodesmata?
Plant specific gap junctions
Channels that connect adjacent cell walls and cytosol
Water and small solutes can pass freely
Can adjust their diameter to allow large molecules to mass through
