Cell membranes Flashcards
What is the cell membrane?
Cell Membrane (Plasma Membrane)The cell
membrane consists of a lipid bilayer that is
semipermeable. The cell membrane regulates
the transport of materials entering and exiting
the cell.
What are the functions of cell membrane?
➢Envelopes (surrounds) the cell.
➢Is the part of the cell that separates its interior component from its outside
environment.
➢Protect the cell contents.
➢Give the shape of the cells
➢Selectively permeable: controls what enters and leaves the cell.
➢Anchors the cytoskeleton elements.
What are the main four functions of the plasma membrane?
The four main functions of the plasma
membrane include identification,
communication, regulation of solute exchange
through the membrane, and isolation of the
cytoplasm from the external environment.
What is cellular identification?
cell–cell recognition occurs when two molecules
restricted to the plasma membranes of different cells
bind to each other, triggering a response for
communication, cooperation, transport, defense, and/or
growth.
What is the part of the cell that identifies cell type?
The part of the membrane that identifies the cell type
is proteins and carbohydrates. All cells have a similar basic
membrane structure of phospholipids arranged in a bilayer.
However, depending on the specialization, there are
different proteins and different carbohydrates on the
external face of the cell.
What is cellular communication?
Cells communicate by sending and receiving signals.
Signals may come from the environment, or they may
come from other cells. In order to trigger a response,
these signals must be transmitted across the cell
membrane. Sometimes the signal itself can cross the
membrane.
Why is the cell membrane crucial for cellular communication?
because it holds the proteins, carbohydrates, and other molecules that are essential to cellular communication. These communications may come from signaling molecules sent by other cells, from cell-to-cell interactions, or from within the cell itself.
What are the categories for chemical signaling?
paracrine signaling, autocrine signaling, endocrine signaling, and signaling by direct contact.
What are the steps for communication?
- Reception: A cell detects a signaling molecule from the
outside of the cell. … - Transduction: When the signaling molecule binds the
receptor it changes the receptor protein in some way. … - Response: Finally, the signal triggers a specific cellular
response.
What is osmosis?
Osmosis is the process by which water molecules
pass through a membrane from a region of higher
water concentration to a region of lower water
concentration.
What are the mechanisms of solute transport?
Solutes can be transported across the plasma membrane
through a variety of methods, diffusion, osmosis, facilitated diffusion and active transport. Passive transport does not require the use of energy (ATP). An example of this is diffusion of particles over the plasma
membrane.
What is something eukaryotes have but prokaryotes dont?
Unlike prokaryotes, eukaryotic
cells also possess internal membranes that encase their
organelles and control the exchange of essential cell
components.
What do specific transport proteins do?
Specific transport proteins (carrier proteins and
channel proteins) then mediate the selective passage of small molecules across the membrane, allowing the cell to control the composition of its
cytoplasm.
What is the difference between general transport methods?
Simple diffusion, Small nonpolar molecules, No energy
Facilitated diffusion, Polar molecules, larger ions, No energy
Primary active transport, Molecules moving against their gradient
coupled to the hydrolysis of ATP, need energy
Secondary active
transport, Molecule going with +
molecule going against
gradient, need energy
How are cell membranes semi permeable?
Cell membranes allow small molecules such as oxygen, water carbon dioxide, and oxygen to pass through but do not allow larger molecules like glucose, sucrose, proteins, and starch to enter the cell directly.
