3. D. 1
1. Explain what
factors are involved in cell communication.
·
Factors that are involved in cell
communication involve a ligand, a molecule that binds to a receptor, the target
detection of a cell, the transduction of the signal and the response it
produces inside of the cell.
2. Explain why
signal transduction process are generally under strong selective pressures.
·
Signal
transduction is a process under selective pressures because in single cell
organisms, it is a response to a cells environment, while a multicellular
organism must communicate with the whole body to support the whole.
3. explain how
signal transduction pathways influence how the cell responds to the environment
using Quorum Sensing as an example.
·
Quorum Sensing is a example of a single
cell responding to its environment. In Quorum Sensing bacteria send out a
protein and that protein will communicate with other bacteria cells around them
and will allow the nearby cells to respond in accordance to its population
density.
4. Why is signal
transduction important?
·
Signal
transduction is important because it allows for the a organism to give a
response from a external change and allow for a multicellular organisms to
support itself as a whole with individual cells.
3.D.2
1. Explain cell to
cell contact communication and give an example.
·
Cell to cell contact signaling is when cells
communicate with direct contact with a cell. For example, plant cells use
plasmodesmata to exchange materials with two cells that are in direct contact
of each other.
2. Explain cell
communication over short distances and give an example.
·
Cell communication over short distances or
paracrine signaling is when cells communicate with regulators that are able to
sense over local vicinity. For example, Quorum sensing is a local vicinity
communication between bacteria
3. Explain cell
communication when signals travel over a long distance and give an example.
·
Cell communication over long distances or
endocrine signaling are signals sent out by one cell type to target cells of
different type (Eukaryotic cells). For example, Insulin is released from the
pancreas and is sent into your blood stream.
3.D.3
1. How does
signaling begin in a signal transduction pathway?
·
Signal transduction begins with a chemical
response called a ligand. A ligand can be a hormone, ion, neurotransmitter or
steroids
2. Explain the ligand
receptor relationship. What does it initiate?
·
The ligand receptor relationship is that
since different receptors recognize different ligands, the ligand causes the
protein to change its shape and initiates a internal signal.
3. Explain a G
protein linked receptor.
·
In a G protein receptor, a ligand binds to
a receptor and once the receptor has attached to a G protein (GDP) and once the
binding has occurred between the ligand and the receptor, it causes the ligand
to replace GDP with GTP. The G protein is then able to break from the receptor
and the G protein can then bind to a area of the membrane called adenylene
cyclase and releases a chemical response called cAMP. And cAMP can then
phosphorylate protein kinase and amplify the signal
4. Explain a ligand
gated ion channel
In a
ligand gated Ion channel, the ligand binds to the neurotransmitter
acetylcholine. The Sodium channel will then open when the acetylcholine binds
to the receptor and this allows sodium to diffuse through the membrane.
5. Explain receptor
tyrosine kinases.
·
In
Tyrosine Kinase, the growth fact binds to the receptor TK and combines to
become a dimer. When the molecules cross, the RTK will take in dimer
phosphorylates called cross phosphorylation. The RTK then activates multiple
signal transduction pathways at once.
6. Signal
transduction is the process by which a signal is converted to a cell response.
Explain the entire process of signal transduction. Use the following terms
(ligand, receptor, protein kinase, secondary messenger, phosphorylation,
transduction, cell response)
·
In signal transduction, a ligand binds to a
receptor and causes a secondary message inside of the cell, this secondary
message will activate a protein kinase and will phosphorylate a cell and begin
a cellular response
3.D.4
1. Conditions where
signal transduction is blocked or defective can alter cell response. Give an
example of when this occurs. What happens?
· A example of a alteration in signal transduction is cholera. Cholera is
a toxin the will modify a G protein and will cause the G protein to not
phosphoralise (GTP > GDP > GDP.)
