Cell Signalling Flashcards
GPCR
What does GPCR stand for?
G-protein coupled receptor
What main olfactory receptor is named OR?
odorant receptor
What are chemo-signals used to access?
type and quality of foods
existence of toxins
the presence and characteristics of predators
Prey
Competitors
potential mates.
In respect to odorants, how do the receptors receiving them differ.
Some receptors are activated by a small number of odorants, whereas others are activated by a larger number of odorants, often with related chemical structures.
Describe the odour space
The odour space consists of small, volatile, mainly fat-soluble, organic compounds with molecular weights between 26 and 300Da.
Describe the mouse olfactory organ
In the mouse nasal cavity, olfactory sensory neurons (OSN) are found within several sensory organs, including the olfactory bulb (OB), accessory olfactory bulb (AOB), main olfactory epithelium (MOE), vomeronasal organ (VNO), septal organ of Masera (SO) and Grueneberg ganglion (GG).
Describe the two ways the receptors in the ciliary OSNs of a mouse MOE are expressed
Receptors expressed include two groups of GPCRs, the ORs and the TAARs, as well as the receptor guanylyl cyclase GC-D. Both ORs and TAARs appear to couple to the G protein Gαolf..
How are vomeronasal sensory neurons divided?
VSNs are divided into apical and basal VSNs. V1Rs are expressed in apical VSNs, while V2Rs are expressed in basal VSNs. Both may couple to layer-specific G proteins (Gαi2and Gαo, respectively).
In summery what do visual GCPRs do?
Converting light stimuli into nerve impulses
Photoreceptor proteinsin the cell absorbphotons, triggering a change in the cell’smembrane potential.
How many rods and cones are there in a human’s retina?
120 million rod cells, and 6 million cone cells.
What’s the definition for a photoreceptor cell?
Aphotoreceptor cellis a specialized type ofneuroepithelial cellfound in theretinathat is capable ofvisual phototransduction.
Describe rod cells
function better in lowerlight (are more sensitive) and are usually found concentrated at the outer edges of the retina and are used inperipheral vision and night vision.
Describe cone cells
respond differently tolightof differentwavelengths, and are thus responsible forcolour vision, and function best in relatively bright light.
What was the 3rd class of photoreceptor recently discovered and what is it thought to do?
Intrinsically photosensitive retinal ganglion cells.
They are thought to be involved in circadian rhythm and support pupillary reflex.
What is a signal to noise ratio?
A measure of the light signal reaching the eye divided by the perceived noise as seen by the eye
Where would signal to noise ratios become apparent?
Different signal-to-noise ratios are apparent in rod-mediated night vision (where the ratio must be high) compared with cone-mediated daytime vision (where the ratio can be lower).
How can fish at greater ocean depths see?
Chlorophyll and other biomolecules in photosynthetic microorganisms selectively ‘consume’ longer-wavelength sunlight, and, as a result, there is a corresponding blueshift in the visual pigment spectral sensitivities of fish that live at greater ocean depths.
What sensory information do Gustatory GPCRs receive?
Taste
Why is the taste map incorrect?
all taste sensations come from all regions of the tongue, although different parts are more sensitive to certain tastes.
What are the different types of taste?
sweet, salty, sour, bitter and umami.
How many tastebuds does the human tongue have?
2000-8000
Why are taste buds useful for an organism in order to decide what to eat?
Enable an organism to determine whether a substance is nutritionally beneficial (eliciting an attractive response) or potentially toxic (eliciting an aversive response)
What taste does toxins from plants have?
Usually bitter
What is the general shape of a taste bud?
Taste buds are onion shaped aggregates (ball/collection of cells)
On average how many cells make up a taste bud and what are these cells called?
50–100 elongate cells
Where do the elongate cells extend to?
elongate cells extend from the basal lamina to the surface of the tongue.
How many types of elongate cell are there? and which one contains GPCRs?
There are three different types, and type II cells are the “receptor cells”, containing GPCRs
What are two types of taste GPCR?
T1Rs and T2Rs
What do T1Rs mediate?
T1Rs mediate sweet and umami (glutamate) taste
What do T2Rs mediate?
T2Rs mediate bitter taste.
What do type II cells release and therefore activate?
Type II cells release ATP as a transmitter, which activates P2X receptors on afferent nerve fibres and P2Y receptors on adjacent taste cells.
What type of affinity receptors are taste receptors?
What range do they have binding affinities to?
taste receptors are low affinity receptors compared to other GPCRs, with binding affinities in the high µM to mM range, which is in the concentration range of most nutrients in foods.
What is differentiation used to regulate?
differentiation is used to regulate, or are synergistic with, pathways that regulate ESC pluripotency
What does ESC stand for?
Embryonic stem cell
What does differentiation affect?
affect the morphology and organization
What does Wnt stand for?
The name Wnt is a blend of the two words: int and Wg and stands for “Wingless-related integration site”.
What do Wnts regulate?
Wnts are secreted factors that regulate cell growth, motility, and differentiation during embryonic development.
How many Wnt proteins are there?
There are 19 Wnt proteins
Are Wnts agonists or antagonists? and what of?
serve as the primary endogenous agonists
In the human genome, how many Fzd receptors are there?
There are 10 Fzd receptors encoded in the human genome
What does Fzd stand for?
Frizzled receptors
What do Fzd receptors/ genes do?
Frizzled genes encode integral membrane proteins that function in multiple signal transduction pathways in animals. They are receptors for secreted Wnt proteins,
