Exam 3: Cell-cell interactions (Class 1) Flashcards
What is an emergent property?
A property that a collection/complex system has, but the individual members do not have
What is epithelial tissue?
A sheet of cells that covers a body surface or lines a body cavity
In order for multicellularity to occur…
cells have to be bound together
Sequence of connections in the epithelium
Epithelial tissue –> basal lamina –> connective tissue
What bears the stresses of tension and compression
The extracellular matrix
What transmits stresses from cell to cell
Cytoskeletal filaments anchored to cell-matrix and cell-cell adhesion sites
What is the condition where mutations in proteins cause epithelia to not adhere to the basal lamina?
Epidermolysis Bullosa
3 types of cell-cell attachments
- tight junctions
- desmosomes
- gap junctions
Function of tight junctions
seal cells together
Function of desmosomes
connect the cytoskeletons of cells
Function of gap junctions
act as channels between cells
What are tight junctions composed of
Specialized proteins
Where are tight junctions located
In the plasma membranes of adjacent animal cells
How do the proteins in tight junctions orient themselves?
They line up and bind to each other
Where do the proteins in tight junctions bind?
Between the two plasma membranes
What does the stitching of the two cells in tight junctions form?
A watertight seal
Which types of tissues are desmosomes common in?
Epithelial and muscle
What do the proteins of desmosomes bind to? (2 answers)
- to each other
- to proteins that anchor intermediate filaments
What are the adhesion proteins in desmosomes?
Cadherins
What is selective adhesion in adult cells?
The way that adult cells attach to each other selectively, attach to the same kind of cell
What are plant cells connected by?
Plasmodesmata
In animal tissues, how do gap junctions connect adjacent cells?
Forming channels
What five things bind adjacent cells to each other?
- middle lamella
- continuous ecm
- tight junctions
- desmosomes
- cadherins
What allows adjacent plant cells to communicate?
Plasmodesmata
What allows adjacent animal cells to communicate?
Gap junctions
What tissue in the human body needs gap junctions, desmosomes, and tight junctions?
Cardiac tissue
What is decellularization?
Removal of cells to isolate the extracellular matrix scaffold
What makes up the ECM? (3 things)
- GAGs
- Proteoglycans
- Fibrous proteins
What are the 4 types of fibrous proteins to know?
- Laminin
- Fibronectin
- Collagens
- Elastin
What is the function of GAGs?
Gel-like squishiness and protection
GAGs are highly ____ charged
negatively
What are proteoglycans?
A polysaccharide (GAG) + a core protein
What is the function of laminin and fibronectin
Connect cells to the ECM and organize components in the ECM
What are the functions of collagens
Provides tensile strength
What is the function of elastin
Stretch and recoil
What is the sequence of how things are attached from cytoskeleton to ECM?
Actin –> integrin –> fibronectins –> collagen
What is the cell wall made of?
Long strands of cellulose
What are the long strands of cellulose in the cell wall bundled into?
Microfibrils
What do the microfibrils in the cell wall form?
A crisscrossed network
What are the two types of cell walls?
Primary and secondary
Where is the primary cell wall?
Between newly made cells
The primary cell wall is __ and __
Thin and flexible
What is the primary cell wall mainly made of?
Cellulose
What keeps the primary cell wall moist?
Pectins and glycans
Which cell wall defines the shape of the cell?
Primary
Where is the secondary cell wall?
Between the plasma membrane and the primary cell wall
What are the three layers between adjacent plant cells?
- primary cell wall of one plant cell
- middle lamella
- primary cell wall of the other plant cell
