Cytoplasmic Inheritance

Present in males and females. 

Usually inherited from one parent, typically the maternal parent.

Reciprocal crosses give different results. 

Exhibit extensive phenotypic variation, even within a single family. 

TLS Online TPP Program

#Id: 9299

#Unit 4. Cell Communication and Cell Signaling

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

TLS Online TPP Program

#Id: 9300

#Unit 4. Cell Communication and Cell Signaling

Rhodopsin has two components: 

Opsin protein, member of the GPCR A family 

11-cis-retinal light-absorbing pigment

TLS Online TPP Program

#Id: 9301

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9302

#Unit 4. Cell Communication and Cell Signaling

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

TLS Online TPP Program

#Id: 9303

#Unit 4. Cell Communication and Cell Signaling

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

TLS Online TPP Program

#Id: 9304

#Unit 4. Cell Communication and Cell Signaling

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