Cell bio Exam 4 - Cell communities and communciation

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Extracellular matrix:

• Functions

  • Supports and anchors cells

  • Cell communication

• Composition

  • Mix of proteins and polysaccharides

  • Secreted from cells via exocytosis

• Can support and anchor the cell 

• Helps with communication 

collagen

______ - extracellular matrix

• Single protein chain

• Becomes triple strand

• Strands assemble into fiber

• Fibers assemble into bundles

• Triple strand comes together to make collagen fibril, which then a bunch of those come together to make collagen fibers 

preotoglycans

______ - extracellular matrix

• GAGs made of repeated sugar elements

• Keratin, Chondrotin sulfate, Hyaluronan

• Proteins link together GAGs

laminin

_____ - extracellular matrix

• Fibrous proteins

integrins

_____ - extracellular matrix

• Used to connect cells to extracellular matrix

• Membrane based proteins 

• Has active and inactive

• Binding to cytoskeleton activates it 

Tight junctions

_______- 

• Seal together 

• Water tight 

Adherens

• Cadherin

______- 

• Connect cells via a structure in the middle 

• _____ protein

Desmosomes

__________- 

• Connect to keratin on the inside of the cell 

Gap junctions-

_______- 

• Connections between cells 

• The other kinds connect the two cells for structural purposes 

• Gap junctions, however, provide direct connections between cells 

• Not selective, anything can go through! 

• When one cell has a bunch of Na+ come in, it transfers it to the other cells too!

Hemidesmosomes

________- 

• Connects cell to basal lamina (extracellular matrix) for structure 

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• First layer: epidermis… there are columnar, squamous, cuboidal, stratified 

  • Pretty stratified, especially at the top 

  • These cells are dead 

  • Melanocytes are in epidermis that produce pigment (below dead cells) 

  • Keratinocytes are also here 

  • Also have immune cells called langerhans 

• Loose connective tissue of dermis

  • Does not have very many cells 

  • Has fibroblasts (make collagen) 

  • Collagen fibers 

  • Immune cells

  • Lymphocytes, macrophages 

  • Capillaries (if you cut yourself and see blood, you have reached at least this layer) 

• Dense connective tissue of dermis 

  • LOTS of collagen (why it's more dense) 

• Fatty connective tissue of hypodermis 

• density

• auto inducer

quorum sensing

• Allow bacteria to sense the _____ of their population

• An ______ is produced by the bacteria constitutively

• The bacteria have a receptor that binds with the auto inducer and starts a signaling cascade

• Switch between low cell density population and high cell density 

• Makes an autoinducer and repector 

• Enough cells need to be together to make an impact to turn things on 

• More cells = more autoinducers = more likely to re enter cell to turn on 

• Constantly being made and received, but need enough to make a difference (penny a day) 

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Regulation- 

• Once autoinducers become equal in all, the concentration on the outside is greater, which makes it stop producing/stop transcription 

• Lipid bi-layer; communication

• replicate

• proteins, nucleic acids, metabolites, organelles

• trash

WHAT ARE EXTRA CELLULAR VESICLES?

• _____ vesicles critical for cellular _____

• Released from lots of different kinds of cells - plants, nematodes, mammalian, microbes

• Can not ____

• Carry ________

• Initially thought to be a way the cell got rid of ____

• Micro Vesicles

• Exosomes

• Apoptotic bodies

• communication

3 Types- 

of extracellular vesicles

• ______ → bud off and can give to another cell 

• _______ → exocytosis, can be used in many biomedical application 

• _____ → Cells bleb off 

• 3 different kinds to be used in _____ 

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EVs- 

• EVs are everywhere and do a lot! 

• Know what they do, but don’t know how they form, if we can induce them, etc.