Research Tweet

Mitochondria

o Mitochondria are the powerhouses of the eukaryotic cell. According to the endosymbiont theory, mitochondria may have evolved from a symbiotic relationship between ancient prokaryotes and eukaryotes.

o Like prokaryotes, mitochondria have their own circular DNA that replicates independently from the eukaryotic cell.

o This DNA contains no histones or nucleosomes.

o Sections of DNA that aren’t in use are wrapped tightly around globular proteins called histones.

o Eight histones wrapped in DNA form a nucleosome.

o Nucleosomes, in turn, wrap into coils called solenoids, which wrap into supercoils.

o Mitochondrial DNA is passed maternally (from the mother) even in organisms whose male gamete contributes to the cytoplasm.

o The genes in the mitochondrial DNA code for mitochondrial RNA that is distinct from the RNA in the rest of the cell.

o Thus mitochondria have their own ribosomes with a sedimentation factor of 55-60 S.

o Antibiotics that block translation in prokaryotes also seem to work in the mitochondria.

o Mitochondria also have some different codons (presenting an exception to the universal genetic code).

o However, most proteins used by mitochondria are coded for by nuclear DNA, not mitochondrial DNA.

Mitochondria Structure

Chemiosmosis, What is Chemiosmosis, Chemiosmosis definition, Chemiosmosis in Photosynthesis, Chemiosmosis process,

o Mitochondria are surrounded by two phospholipid bilayers.

o The inner membrane invaginates to from the cristae.

o It is the inner membrane that holds the electron transport chain.

o Between the inner and outer membrane is the intermembrane space (lower pH and higher [H+] than the matrix).

o Organelles with two membranes: nucleus, mitochondria, and chloroplast.

Mitochondria Function

o TCA / Krebs Cycle: (aerobic, occurs in the cytoplasm for prokaryotes, mitochondrial matrix for eukaryotes).

Citations

Share

Share on facebook
Share on twitter
Share on linkedin
Share on whatsapp
Share on email
Share on telegram
Share on google
Share on pinterest
Share on vk
Share on odnoklassniki
Share on tumblr
Share on pocket
Similar Post:

0 0 votes
Article Rating
Subscribe
Notify of
guest
0 Comments
Inline Feedbacks
View all comments
0
Would love your thoughts, please comment.x
()
x