Specific exonic and intronic sequences can enhance or suppress splice site selection.

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.

TLS Online TPP Program

#Id: 7897

#Unit 2. Cellular Organization

Chloramphenicol, blocks protein synthesis by bacterial and mitochondrial ribosomes

Cycloheximide, does not affect protein synthesis by mitochondrial ribosomes

TLS Online TPP Program

#Id: 7898

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 7899

#Unit 2. Cellular Organization

Only 22 tRNAs are required for mitochondrial protein synthesis. The normal codon–anticodon pairing rules are relaxed in mitochondria, so that many tRNA molecules recognize any one of the four nucleotides in the third (wobble) position, allowing four codons to be recognized by a single tRNA.

TLS Online TPP Program

#Id: 7900

#Unit 2. Cellular Organization

Leber’s hereditary optic neuropathy

caused by a missense mutation in the mtDNA gene

encoding subunit 4 of the NADH-CoQ reductase

TLS Online TPP Program

#Id: 7901

#Unit 2. Cellular Organization

Deletions in mtDNA cause another set of diseases:

Chronic progressive external ophthalmoplegia

Kearns–Sayre syndrome