Chapter 6 Cell communication Flashcards
cell signaling
Mechanisms of communication between cells. Cells
signal one another with secreted signaling molecules, or a signaling molecule on one cell combines with a receptor on another cell.
reception
Process of detecting a stimulus.
target cells
A cell or tissue with receptors that bind a
hormone.
signal transduction
process in which a cell converts and amplifies an extracellular signal into an intracellular signal that affects some function in the cell.
response
any behavior of a living organism that results from an external or internal stimulus.
neurotransmitters
A chemical signal used by neurons to transmit
impulses across a synapse
Hormones
A chemical messenger, oft en produced in one region of the body of a multicellular organism and transported to another region where it signals cells to alter some aspect of growth, development, or metabolism.
endocrine glands
A gland that secretes hormones directly
into the blood or tissue fluid instead of into ducts.
Local regulators
Prostaglandins (a group of local hormones), growth
factors, cytokines, and other soluble molecules that act on nearby cells by paracrine regulation or act on the cells that produce them (autocrine regulation).
paracrine regulation
A type of regulation in which a signal molecule (e.g., certain hormones) diffuses through interstitial fluid and acts on nearby target cells.
prostaglandins
A group of local regulators derived from fatty acids; synthesized by most cells of the body and produce a wide variety of effects; sometimes called local hormones.
nitric oxide
A gaseous signaling molecule; a neurotransmitter.
ion channel–linked receptor
are cell membrane bound receptors. They act through synaptic signaling on electrically excitable cells and convert chemical signals (ligand) to electrical ones.[1] It is essential in neuronal activities.
G protein–linked receptors
a large protein family of receptors that sense molecules outside the cell and activate inside signal transduction pathways and, ultimately, cellular responses. are found only in eukaryotes, including yeast, choanoflagellates,[3] and animals.
G protein
One of a group of proteins that bind GTP and are involved
in the transfer of signals across the plasma membrane.
Enzyme-linked receptors
also known as a catalytic receptor, is a transmembrane receptor, where the binding of an extracellular ligand causes enzymatic activity on the intracellular side.[
Intracellular receptors
Receptors located inside the cell rather than on its cell membrane. Classic hormones that use intracellular receptors include thyroid and steroid hormones.
protein kinase cascade
A signaling pathway in which a series of protein kinase molecules are phosphorylated
guanosine
diphosphate (GDP)
consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase guanine.
guanosine triphosphate
GTP
An energy transfer molecule similar to ATP that releases free energy with the hydrolysis of its terminal phosphate group.
transcription factors
a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the rate of transcription of genetic information from DNA to messenger RNA.
first messenger
extracellular factor that elicits a response within a cell. As such, first messengers are incredibly diverse, ranging from environmental factors, such as light or heat, to small molecules and peptides, up through large multivalent proteins.
second
messenger
are intracellular signaling molecules released by the cell to trigger physiological changes such as proliferation, differentiation, migration, survival, and apoptosis. Examples of second messenger molecules include Cyclic AMP, Cyclic GMP, Inositol Triphosphate, Diacylglycerol, and Calcium.
adenylyl cyclase
Is an enzyme with key regulatory roles in essentially all cells. Adenylyl cyclase catalyze the conversion of adenosine triphosphate (ATP) and pyrophosphate.
cyclic AMP (cAMP)
A form of adenosine monophosphate in which the phosphate is part of a ring-shaped structure; acts as a regulatory molecule and second messenger in organisms ranging from bacteria to humans.
protein kinase
One of a group of enzymes that activate or inactivate
other proteins by phosphorylating (adding phosphate groups to) them.
inositol trisphosphate (IP3)
A second messenger that increases intracellular calcium concentration and activates enzymes.
diacylglycerol (DAG)
A lipid consisting of glycerol combined chemically with two fatty acids; also called diglyceride. Compare with monoacylglycerol and triacylglycerol.
calmodulin
A calcium-binding protein; when bound, it alters the
activity of certain enzymes or transport proteins.
Signal amplification
The process by which a few signaling molecules can effect major responses in the cell; the strength of each signaling
molecule is magnified.
Signal termination
a specific sequence in DNA at which the RNA polymerase and the newly made RNA transcript are released from their DNA association.
biofilm
community of microorganisms attached to a solid surface
Receptors
large proteins or glycoproteins that bind with signaling molecules. Many types of signaling molecules do not actually enter the target cell.
interstitial fluid
the fluid surrounding the cells, and acts on nearby cells.
Histamine
is a local regulator that is stored in certain cells of the
immune system and is released in response to allergic reactions, injury, or infection
Ligand
a molecule, other than an enzyme, that binds specifically to a macromolecule (usually a protein), forming a macromolecule-ligand complex Most ligands are hydrophilic molecules that bind to protein receptors on the surface of target cells
rhodopsin
is part of a signal transduction pathway that leads to vision in dim light.
phytochromes
family of blue-green pigment proteins that are activated by red light. Activation can lead to changes, such as flowering
cryptochromes
pigments that absorb blue light. Cryptochromes play a role in biological rhythms.
receptor down-regulation.
the concentration of the hormone insulin is too high for an extended period, cells decrease the number of their insulin receptors.
Receptor up-regulation
occurs in response to low hormone concentrations amplifies the signaling molecule’s effect on the cell.
acetylcholine
a neurotransmitter that binds to an acetylcholine receptor. This receptor is a ligand-gated sodium ion channel that is important in muscle contraction.
kinase
enzyme that transfers the terminal phosphate group from ATP to a substrate This process is called phosphorylation
tyrosine kinase
an enzyme that catalyzes the transfer of phosphate groups from ATP to a specific tyrosine that is part of a protein. (Tyrosine is an amino acid.)
Brassinosteroids (BRs)
group of plant steroid hormones, regulate many plant processes, including cell division, cell elongation, and flower development
ethylene
plant hormone that regulates a variety of processes, including seed germination and ripening of fruit. Ethylene is also important in plant responses to stressors.
phosphatase
enzyme that catalyzes the removal of a phosphate group by hydrolysis; the process is called dephosphorylation. Protein phosphatases help regulate protein kinase cascades
Gamma-aminobutyric acid (GABA)
neurotransmitter that binds to GABA receptors. One class of GABA receptors consists of ligand-gated chloride ion channels.
phosphodiesterase
an enzyme that converts cAMP to adenosine monophosphate (AMP)
