Looks like no one added any tags here yet for you.
signal transduction pathway
chemical reactions that lead to a cell's response to a signal, involves reception, transduction, and a response
specificity
only cells with the correct "specific" receptors will respond to the signal.
conformation change
A change in the shape of a receptor protein caused by binding of the ligand.
ligand
a signal molecule that bonds to a receptor that initiates a cellular response
ligand releases
results in the conclusion of a signal transmission
binding of ligand to receptor is reversible
non-covalent, binding is favored but it can be undone so that stimulation does not last forever
Step 1
Reception: A ligand binds to a receptor protein
3 kinds of plasma membrane receptors
1.ion channel receptors 2. protein kinase receptors 3. g linked protein receptors
ion channel receptors
gated ion channels are opened by a conformation change. Ex. ligand gated calcium channels
protein kinase receptor
receptors change shape upon binding., creating dimers that allow phosphorylation and in turn activates relay proteins.
protein kinase
catalyzes the breakdown of ATP to ADP. The addition of the removed phosphate to a protein, activates the protein
ATP + Protein ---> ADP + Phosphorylated protein
phosphorylation
adding/transferring a phosphate group to a molecule. Activates protein.
Phosphorylated protein= active
Dephosphorylated protein= inactive
g protein
A receptor protein with three polypeptide subunits that can bind to
1. the receptor
2. GDP.GTP
3. An effector protein
effector/ accessory protein
a protein in a g protein linked receptor signal transduction that can cause an effect in the cell
amplification
One ligand binding can result in many signaling cascades within the cell.
protein phosphatase
Enzyme responsible for the removal of phosphate from an active protein.
Step 2
Transduction: a series of molecular events, most commonly protein phosphorylation catalysed by protein kinases,
Step 3
Response: The final event occurring as a result of signal transduction.
secondary messenger
Released by the cell in response to binding of a ligand to a receptor. Messengers initiate components of intracellular signal transduction cascades. Examples: cyclic AMP, cyclic GMP, inositol trisphosphate, diacylglycerol, and calcium.
signal cascade
A series of chemical reactions within the cell as a result of reception of an external stimulus.
ATP
The source of phosphate in many signal pathways. Dephosphorylated molecule is ADP.
GTP
The source of phosphate in many signal pathways. Dephosphorylated molecule is GDP.
transcription
The initiation of the expression of a particular gene. Often the response of a cell to signal transduction.
protein kinase
a type of protein kinase responsible for phosphorylating proteins in RTKS.
G1 Phase
Primary growth phase of the cell
S Phase
Phase where DNA is replicated
G2 Phase
Growth stage in which the cell prepares for division; organelles replicate and spindle forms
Interphase
Collective name for G1, S, and G2 Phases
Mitosis (M)
Division of the nucleus
Cytokinesis (C)
Cytoplasm divides; forms 2 daughter cells
Chromosome
coiled DNA; visible
Spindle
Consists of fibers made of microtubules and associated proteins; location where chromosomes attach
Prophase
Chromatin fibers condense into chromosomes, mitotic spindle begins to form, centromeres move away from each other
Metaphase
Centrosomes at opposite poles of the cell, Chromosomes convene at metaphase plate
Telophase
Two daughter nuclei form in the cell, nuclear envelope forms
G1 Checkpoint
Most important checkpoint; if cell receives go-ahead signal, the the cell continues with the cell; in the absence of the go-ahead signal, cell exits the cell cycle and enter the G0 phase
M Checkpoint
Cell in mitosis receives a stop signal when any of its chromosomes are not attached to spindle fibers
Cancer
Uncontrolled dividing of cells
Undifferentiated
Description of a stem cell
Homologous
Describes a pair of chromosomes; one maternal and one paternal
Chromatin
uncoiled DNA; found during interphase
Diploid
A cell with two copies of each chromosome
Haploid
A cell with half the number of chromosomes
Meiosis
Process by which gametes are made
Crossing Over
Occurs during meiosis; increases genetic variation
Mutation
Any change in DNA
Binary Fission
The way in which bacteria reproduce; copy and split
G0 (G zero)
Resting state for cells not dividing
Density-Dependent Inhibition (Contact Inhibition)
Cells stop dividing when it's too crowded in an area
Cyclin
Protein that increases and decreases throughout the cell cycle and activates enzymes needed for division
2 Divisions
A description of the events in meiosis
1 Division
A description of the events in mitosis
46
Represents the number of chromosomes in a human somatic cell.
23
Represents the number of chromosomes in a human gamete.