Eukaryotic Structure 4 Flashcards
(9 cards)
Describe the structure of mitochondria
- Outer membrane=
Permeable to small molecules
Contains large, channel-forming proteins called porins - Inner membrane=
Folded into cristae
Contains proteins for electron-transport chain and ATP Synthase
Impermeable to most molecules - Matrix=
Contains enzymes for Krebs cycle, mitochondrial DNA genome and ribosomes and tRNA - Intermembrane space=
Important for the protein gradient used in ATP synthesis
How is ATP produced in the mitochondria?
Occurs on mitochondrial inner membrane
1. Acetyl-CoA production
2. Electrons carriers: NADH and FADH2
3. Move through the electron transport chain
4. Creates an electrochemical gradient
5. Protons flow back into mitochondrial matrix
6. “Turn” ATP synthase and create ATP
What are some causes of mitochondria dysfunction ? Name some diseases that it causes
Genetic mutations
Toxins
Mitochondrial encephalopathy, lactic acidosis and stroke-like episode syndrome (MELAS)
Structure or chloroplasts
- Double membrane- inner and outer
- Thylakoid- contains molecular machinery for photosynthesis
- Stroma- fluid filled matrix that contains enzymes etc.
What size are eukaryotic ribosomes ?
80S
Made up of a 40S subunit and a 60S subunit
What size are bacterial ribosomes ?
70S
Made up of a 50S subunit and a 30S subunit
What is a ribozyme ?
An RNA and an enzyme
Describe the structure of ribosomes
Small unit- binds to mRNA, responsible for reading the genetic code
Large unit- joins amino acids together to form a polypeptide chain, has the peptidyl transferase activity
They contain 4 binding sites: one for mRNA and 3 for tRNA
Describe translation
- Small subunits binds to mRNA
- tRNA carrying Met binds to start codon
- Large subunit joins
- tRNAs bring AA to the ribosome, forming peptide bonds between AA
- Ribosome moves along the mRNA and the chain grows until a stop codon is reached
