Organelle Origin Flashcards
1
Q
What’s an organelle?
A
- Simply a concept
- Ex: are sulcia and hodgkinia in a cicada bacteria or organelles if all three need each other for survival?
2
Q
What does Planctomyces show?
A
- Eukaryotes are also just a concept and their definition of “anything with a nucleus” isn’t quite right
- Bacteria with a membrane bound nucleus (bacterial membrane composition not eukaryotic)
3
Q
endocytic membranes rane trafficking
A
involves the cellular internalization and sorting of extracellular molecules, plasma membrane proteins and lipids
4
Q
What is required for nutrient uptake, cell adhesion and migration, receptor signaling, pathogen entry, and cell polarity?
A
endocytosis
5
Q
How can we determine intracellular localization?
A
- make extracts then western blot
- make a fusion of the protein in interest with a florescent protein and use microscopy
- ex: GFP and YFP
- use florescent antibodies against the protein of interest
- Problem: need compartment specific markers as controls
6
Q
How can we test if a planctomyces is capable of endocytosis?
A
- incubate cells with GFP and look for uptake
- endocytosis requires ATP
- create control where you inhibit mitochondrial activity
- create control where you inhibit mitochondrial activity via sodium azide but add external ATP
- see if GFP still internalizes
7
Q
ancestral mitochondrial genome
A
- encodes more genes
- bacterial rRNA
- Large subunit, small subunit, 50s rRNA
- complete tRNA set
- few introns
- standard genetic code
8
Q
derived mitochondrial genome
A
- extensive gene loss (protein coding and tRNAs)
- divergent rRNA structure and sequence
- biased codon usage (complete elimination of some codons)
- nonstandard codon assignments
- UGA (STOP) is a Trp codon in many mitochondria
9
Q
codon bias
A
- some organisms use certain codons preferentially for the same amino acid
- ex: GGA, GGC, GGG, GGT are all glycine
- but many bacteria prefer GGA and GGT
