Karteikarten
26: Cell Communication
Karten in diesem Stapel (38)
- 1unicellular vs multicellularUnicellular relies on diffusion
Multicellular can multitask, store fat/food
There is an evolutionary pull to be multicellular - 2what does being big and allowing differentiation promoteevolution of multicellular organisms
- 3how do the majority of cells formclonal development
- 4what is needed for multicellular organisation?1. cell adhesion - stick cells together
2. cell to cell communication and coordination
3. programmed cell death - 5what is clonal developmenta single spore/zygote divides and the cell stay stuck together
- 6What are the types of cell junctions in animal cells- Tight junction
- Adherens junction
- Desmosome
- Gap junctions - 7Tight junction- Leak proofing
- Seals neighbouring cells together to prevent leakage
- Formed by: claudins and occludins - 8what forms tight junctionsclaudins and occludins
- 9Adherens junction- Adhesion
- Joins actin bundles in one cell with actin bundles in a neighbouring cell
- Formed by: cadherins - 10what are adherens junctions formed byCadherins
- 11Desmosome- Adhesion
- Similar to adherens but a different type of cadherin connects intermediate filaments from one cell with intermediate filaments from a neighbouring cell - 12Gap junctions- Communication
- Water filled channels - connect the cytoplasm of one cell with the cytoplasm of the neighbouring cell
- Allows movement of ions and small water-soluble molecules btwn cells
- Formed by: connexons - 13what forms gap junctionsConnexons
- 14whats the cell junctions in plantsplasmodesmata
- cells are glued together by the middle lamella and communicate via specialised openings - 15why do cells need to communicate- to respond to changing environment
- to communicate with other cells - 16what is cell communication often referred to ascell signalling
- 17what is cell signalling fundamental tonormal cell behaviour and whole organism physiology
- disruption to normal cell signalling processes underlies most disease states - 18What are the essential components of a signalling system?1. A cell that registers a stimulus and so secretes a:
2. Signal molecule - level of secretion being in proportion to intensity of the stimulus
3. Target cell - responds to the signal and changes it biochemical activity in a specific way in response. Intensity of the response is in proportion to the concentration of the signal molecule - 19what is a stimulusa change in the environment
- 20what is cell signallinga process where a change in the circumstances of one cell can result in the change in the activity of another cell
- 21what is a good example of a single-celled organism that has developed cell signalling systems to coordinate the activity of its communitythe slime mold
(Dictyostelium discoidum) - 22Slime mold example of coordination of activity of multiple cells for overall benefitfeeds on bacteria in soil, exists singularly (as amoeba) when there is lots of food.
1. Starving cells secrete a signalling molecule as chemoattractant and aggrefate
2. multicellular 'mound' - differentiation into prespore and prestalk cells
3a. Bad Conditions: migrating slug moves away to find better conditions
3b. Good Conditions: Terminal Differentiation into spore and stalk cells - spore disposal to new areas - food resources - 23what has evolution of multicellular organisms led tothe development of the multitude of complex cellular signalling systems
- 24what is cell differentiationdifferent cells within the same organism become specialised in carrying out different tasks or processes
- 25what does each cell specialise in for cell signallingspecialises in a limited array of biochemical activities - for the benefit of the overall organism
- 26why is coordination neededneeds of the whole organism may not always coincide with the immediate best activity of individual cell type
- 27what are the 3 processes of cells receiving signals?1. Reception
2. Transduction - relay molecules in a signal transduction pathway
3. Response - multiple outcomes - 28the binding between a signal molecule and receptor is ________highly specific
- 29what is often the initial transduction of the signala shape change in the receptor
- 30what can multistep pathways do1. amplify a signal
2. provide more opportunities for coordination and multiple cellular responses - 31What can the end-point target of the transduction pathway be1. An Enzyme - altered cell metabolism
2. A Structural protein - altered cell shape; movement
3. A Transcription Factor - altered gene expression which changes the types and the amounts of proteins within the cell - 32what are the 6 different types of intercellular signalling?1. contact dependant
2. paracrine
3. autocrine
4. endocrine
5. synaptic
6. gap junctions - 33Contact dependent signalling- Requires cells to be in direct membrane-membrane contact
- Important in development and immune response - 34Paracrine Signalling- Signalling molecules released into extracellular space - act locally - do not travel far as they are taken up by neighbouring cells, destroyed by enzymes or immobilised by the matrix
- 35autocrine signalling- Cells secrete signals that act back on their own receptors as well as neighbouring cells
- Important in development
- 36Endocrine signalling- Cells secrete hormones into bloodstream and distributed widely throughout body
- only cells with appropriate receptors respond
- 37synaptic signallingneurones transmit signals electrically along axons and release neurotransmitters at synapses
- 38gap junctionsspecialised cell-cell junctions that allow exchange of small intracellular molecules
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- Biology (101) Karteikarten am 26: Cell Communication, erstellt von max brain am 21/12/2017.
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