Mitochondrion, energy transduction, nuclear transport

Main features on mtDNA

Circular

Small

Several copies in every mitochondrion

Similar to bacterial DNA

Few regulatory sequences

Mutation rate is high

Inheritance differed from Mendelian principles

Triples work different

Transcription is symmetrical

Features of mitochondrial division

Growth is due to increased protein and liquid imports, as well as DNA replication

Similar to bacterial fission

Can occur at any time

Glycolysis

1 mol of glucose is oxidized into 2 pyruvate

Takes place in cytosol

Glycolysis products

2 pyruvate + 2ATP + 2NADH

Citrate cycle products

2CO2 + 3NADH + 3H+ + FADH2 + GTP + CoA

Oxidative phosphorylation

Takes place in inner membrane

NADH and FADH2 are oxidised

Complex 1

NADH dehydrogenase

Complex 2

succinate-UQ-oxidoreductase

Complex 3

UQH2-cytochrome-c-oxidoreductase

Complex 4

Cytochrome oxidase

F0 ATP synthase

transmembrane proton channel

Transports H+ ions from intermembrane space to matrix

F1 ATP Synthase

Has a catalytic function

rotates

Synthesizes ATP from ADP + Pi

Chemioosmotic mechanism

ATP synthesis powered by proton flow

Steps of mitochondrial protein import

Precursor protein w/ signal sequence binds to import receptors

Insertion of protein into membrane by TOM complex

Translocation of protein into matrix

Cleavage by signal peptidase

Ions, small molecules (<5000 Da)

Free diffusion

Large molecules (RNA and large proteins)

active transport