In bright light, little transducin is found in the outer segment, and abundant arrestin is found there; in this condition,vision is relatively insensitive to small changes in light.

TLS Online TPP Program

#Id: 7891

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 7892

#Unit 2. Cellular Organization

mtDNA is located in the mitochondrial matrix, and in the rapidly growing cells, mtDNA is often seen in regions devoid of densely stacked cristae.

TLS Online TPP Program

#Id: 7893

#Unit 2. Cellular Organization

A human cell has about 1000–2000 mtDNA molecules

A human egg has about 500,000 mtDNA molecules

A sperm has only about 100 mtDNA molecules

TLS Online TPP Program

#Id: 7894

#Unit 2. Cellular Organization

The mtDNAs of most multicellular animals are approximately 16-kb circular molecules that encode intron-less genes compactly arranged on both DNA strands.

TLS Online TPP Program

#Id: 7895

#Unit 2. Cellular Organization

Vertebrate mtDNAs encode 2 rRNAs, 22 tRNAs, and 13 proteins involved in electron transport and ATP synthesis. 

TLS Online TPP Program

#Id: 7896

#Unit 2. Cellular Organization

The smallest mitochondrial genomes in Plasmodium, are only about 6 kb, encoding three proteins and the mitochondrial rRNAs.

Arabidopsis thaliana, has 366 kb of mtDNA and cucurbit plants have about 2 Mb of mtDNA.