Plasma Membrane
outer layer of the cell, responsible of multiple functions
Functions of the Plasma Membrane
1. Provides structure
2. Protection and barrier from toxic molecules and macromolecules
3. Activation of the Cell - contains multiple receptors
4. Transport
5. Cell-to-cell inter...
Plasma Membrane - ANSWER- outer layer of the cell, responsible of multiple
functions
Functions of the Plasma Membrane - ANSWER- 1. Provides structure
2. Protection and barrier from toxic molecules and macromolecules
3. Activation of the Cell - contains multiple receptors
4. Transport
5. Cell-to-cell interaction
Contents of the plasma membrane - ANSWER- Basic structure is composed of
the "lipid bilayer", contains CHOLESTEROL AND LIPIDS. It is semipermeable,
allows molecules such as O2 and CO2 inside the cell.
Major components of the plasma membrane - ANSWER- are lipids and proteins
Cellular Communication - ANSWER- Three main ways:
1. signaling molecules
2. receptor proteins
3. protein channels - gap junctions
contact-dependent signaling - ANSWER- requires for cells to be in close
membrane-membrane contact
paracrine signaling - ANSWER- secrete local mediators that are quickly absorbed,
destroyed, or immobilized -- involves diff cell types
hormonal signaling - ANSWER- a type of long-distance signaling where an
endocrine excretes hormones in a blood vessel to travel to a target cell
, neurohormonal signaling - ANSWER- hormones released into bloodstream by
neurosecretory neurons via synapses -- angiotensin 2
Signal Transduction - ANSWER- signaling cell + target cell + protein + appropriate
response
Apoptosis - ANSWER- programmed cell death, if deprived of appropriate signals,
most cells undergo a form of cell suicide
Apoptosis vs. Necrosis - ANSWER- Apoptosis- active, orderly and organized;
minimal if any inflammation
Necrosis- passive and disorderly; inflammatory process seen
Cellular Receptors - ANSWER- protein molecules on the plasma membrane, in the
cytoplasm or in the nucleus that are capable of recognizing and binding w
specific smaller molecules - LIGANDS
examples of ligands - ANSWER- hormones, neurotransmitters, antigens, drugs
Ligand - ANSWER- a signaling molecule that will be matched with a specific
receptor (receiving molecule), important and key for cell communication..
Receptors only recognize specific ligands and viceversa
proteins - ANSWER- MAJOR WORKHORSES OF THE CELL
Facilitate transport across membranes by serving as receptors, enzymes or
transporters
Functions of proteins - ANSWER- 1) recognition and binding units
2) pores or transport channels
3) act as specific enzymes
4) cell surface markers (i.e. glycoproteins)
5) cell adhesions
6) catalyst
7) membrane proteins
outside the cell - ANSWER- Na+ is greater
inside the cell - ANSWER- K+ is greater
Cell Transport - ANSWER- May be active (energy requiring) or passive
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