Hormone types and the intracellular signalling pathways Part 2 Flashcards
(42 cards)
What is cell signalling
Cell signalling includes hormonal communication but is wider because it also includes intracellular signalling - what happens inside the cell when an external communication is received,
What is signal transduction? And in cells?
Process of converting one type of signal into another.
Primary messenger -extracellular signal molecule- secondary messenger - intracellular signalling molecule
What do receptors do in terms of cell signalling?
Receptors on cell surfaces receive incoming signals and produce intracellular signalling molecules that alter cell behaviour.
What are the main differences between types of cell signalling
Speed and sensitivity
What are the different types of cell signalling
Neuronal
Contact-dependant signalling
Paracrine
Endocrine
What is the speed and selectivity for neuronal signalling
Very fast
Very selective
What is the speed and selectivity for contact dependent signalling
Very fast
Very selective
What is the speed and selectivity for paracrine signalling
Slow
Less selective
What is the speed and selectivity for endocrine signalling
Slow
Less selective
What is neuronal signalling
Action potentials are transmitted electrically along a nerve cell “axon’. When this signal reaches the nerve terminal, it causes the release of neurotransmitters onto adjacent cells,
What is contact dependent signalling
a cell-surface-bound signal molecule binds to a receptor protein on an adjacent cell. No molecules are released.
What is paracrine signalling
Paracrine signals are released by cells into
the extracellular fluid in their neighbourhood and act as local mediators.
What is endocrine signalling
Hormones are secreted into the bloodstream and are distributed widely throughout the body
What are the two basic types of signal molecule/ receptor interaction
Cell surface receptors
Intracellular receptors
What is cell surface receptor/ signal molecule interaction?
Most extracellular signal molecules are large and hydrophilic and are therefore unable to cross the plasma membrane. Instead, they bind to cell-surface receptors which generate intracellular second messenger signalling molecules
What is intracellular receptor/ signal molecule interaction?
Intracellular receptors. Some small, hydrophobic, extracellular signal molecules pass through the target cell’s plasma membrane and bind to intracellular receptors in the cytosol or the nucleus as shown here) that then regulate, for example, gene transcription.
What is true about signal molecules and their effect on different cells? Example
The same signal molecule can induce different responses in
different target cells
Acetylcholine
Heart pacemaker cell- Decreased rate of firing
Salivary gland- secretion
Skeletal muscle cell- contraction
What is true about cells receiving signals
Cells can receive and respond to many signals simultaneously
Every cell type displays a set of receptor proteins that enables it to respond to a specific set of extracellular signals produced by other cells.
The signal molecules work in combinations to regulate the behaviour of the cell-
Cells may require multiple signals to survive…
additional signals to grow and divide,
still other signals to differentiate.
If deprived of the necessary signals, most cells undergo a form of cell suicide known as apoptosis.
Which processes using cell signalling are fast and which are slow
Processes that rely on altered protein function - such as movement, secretion and metabolism - are fast.
Processes that rely on altered protein synthesis - such as differentiation, growth and division - are slow.
Explain the process of cell surface receptor and signal interaction
Extracellular signals activate intracellular signalling pathways which are mediated by a series of intracellular signalling molecules which can be proteins or smaller chemicals. Signalling molecules eventually interact with specific effector proteins.
What are three main types of cell surface receptor?
Ion channelled receptors
G-protein-coupled receptors(GPCRs)
Enzyme-coupled receptors
What is an ion channel coupled receptor
Binds to signalling molecule which allows/ or doesn’t allow it to let ions pass through
Where do you find
In the nervous system
What are ion channel coupled receptor also known as
transmitter-gated ion channel
