Diphtheria

Natural infection with C. diphtheriae occurs only in humans and is spread by respiratory droplets. 

The organism colonizes the nasopharyngeal tract and causes little tissue damage, with only a mild inflammatory reaction. 

TLS Online TPP Program

#Id: 9299

#XL - T Zoology

Rod cells sense light with the aid of a light-sensitive GPCR called rhodopsin.

TLS Online TPP Program

#Id: 9300

#XL - T Zoology

Rhodopsin has two components: 

Opsin protein, member of the GPCR A family 

11-cis-retinal light-absorbing pigment

TLS Online TPP Program

#Id: 9301

#XL - T Zoology

TLS Online TPP Program

#Id: 9302

#XL - T Zoology

11-cis-retinal covalently attached to the amino group of lysine residue 296 in the opsin protein

TLS Online TPP Program

#Id: 9303

#XL - T Zoology

The heterotrimeric G protein coupled to rhodopsin, called transducin (Gt)

TLS Online TPP Program

#Id: 9304

#XL - T Zoology

In the absence of light,  bound 11-cis-retinal locks the rhodopsin into its inactive (R) conformation