Transcript Animal report presentation

CELL
COMMUNICATION
Let’s Review!
Copyright © Amy Brown – Science Stuff
Name three ways that cells can
communicate with one another.
1. Cells can sense and respond to electromagnetic
signals such as light.
2. Cells can respond to mechanical signals such as
touch.
3. Cells can communicate by chemical signals.
Chemical signaling is the most common.
How are chemical signals received
by a cell?
Cells have receptor proteins embedded in the cell
membrane. Chemical signals must have a
complimentary shape to bind to the receptors at the
cell surface.
What is a signal transduction
pathway?
The process by which a signal at the cell’s surface is
converted into a specific cellular response in a series
of steps.
How long have cells been signaling
each other?
For as long as there have been cells.
Do communicating cells have to be
close together?
No, cells can communicate over long distances.
What cellular structures might be used for
communication between two cells side by
side?
There are cell junctions between cells.
Gap junctions are found between animal cells, and
plasmodesmata are found between plant cells.
Through these junctions molecules may freely pass
without having to cross the cell membrane.
Explain this picture.
Proteins on the surface
of each cell have
compatible shapes.
These protein receptors
are involved in cell-cell
recognition.
The interaction between
these protein receptors
allows the cells to
communicate.
What are local regulators?
A local regulator is a chemical substance secreted by
a cell that is transmitting a message. This chemical
substance influences cells in the immediate vicinity.
What are the two ways to carry out local
signaling?
Paracrine signaling
Synaptic signaling
Describe paracrine signaling.
The transmitting cell secretes the local regulator
(chemical signal) into the fluid surrounding the cells
of a tissue.
The local regulator diffuses across the liquid.
The local regulator binds to protein receptors at the
cell surface of the target cells.
The target cells respond.
In what type of cells does synaptic signaling
occur?
This type of signaling occurs between nerve cells in
the animal nervous system.
Describe synaptic signaling.
A nerve cell releases a neurotransmitter into the
synapse.
A synapse is the space or gap between two nerve
cells.
The neurotransmitter diffuses across the synapse to
reach the target cell.
The neurotransmitter binds to receptor proteins at
the surface of the target cell.
What are two differences between paracrine
and synaptic signaling?
1. Paracrine signaling produces molecules of a
local regulator. Synaptic signaling produces
neurotransmitters.
2. Paracrine signaling affects all cells in the vicinity
of the transmitting cell. Synaptic signaling affect
a single target cell.
How do both plant and animal cells
accomplish long distance signaling?
Hormones are chemical messengers that can travel
long distances to reach their target cells.
In animals, how do hormones reach their
target cells?
The hormone is released into the blood stream and
travels through the blood vessels to reach the target
cell.
In plants, how do hormones reach their
target cells?
In plants, hormones move by traveling through cells.
The hormone passes from cell to cell.
Plants hormones may also diffuse through the air as
a gas.
How do cells communicate through direct
contact?
Both plants and animals have cell-cell junctions.
Signaling substances that are dissolved in the
cytoplasm can pass freely to the new cell through
these junctions.
What are the three stages of cell signaling?
Reception
Transduction
Response
In the three stages of cell signaling, define
“reception”.
The target cell detects the incoming signal.
The signal is detected when the chemical
signal binds to receptor proteins at the cell
surface.
In the three stages of cell signaling, define
“transduction”.
The conversion of a signal from the outside of
a cell to a form that can bring about a specific
cellular response.
In the three stages of cell signaling, define
“response”.
The appropriate behavior or response is
carried out by the cell.
How does the chemical signal “know”
when it has reached the target cell?
The shape of the chemical signal protein must
be complimentary to the receptor protein
located in the cell membrane.
What is the importance of this system of
cell signaling?
It insures that cells carry out the proper
activities at the right time, and in coordination
with the other cells of that particular tissue.
Where are most receptor proteins found?
At the cell surface
What do receptor proteins do?
They transmit information from the
extracellular environment to the inside of the
cell through a change in conformation
(shape).
A few receptor proteins are found on the
inside of the cell and not at the cell surface.
How does the signaling molecule reach the
receptor protein?
The signaling molecule is small and
hydrophobic so that is can cross the lipid
bilayer of the cell membrane.
Why are there so many steps between the
signaling event at the cell surface and the
cell’s response?
1. The signal may be amplified along the
way.
2. It contributes to the specificity of the
response.
Why do some cells respond to a chemical
signal while other cells do not?
Different kinds of cells have different
collections of receptor proteins. A cell
may receive the signal, but if the
complimentary receptor protein is not
found on that cell, there will be no
response.
How is a signal terminated once the cell has
carried out the proper response?
The signaling molecule leaves the receptor
protein.
What is apoptosis?
This is controlled cell destruction. It may
occur in cells that are infected, damaged,
or too old to carry out their functions.
Created by Amy Brown – Science
Stuff
Copyright © February 2013 Amy
Brown (aka Science Stuff)
All rights reserved by author.
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