Molecular Energy Transformations: Classification Flashcards
What are the 3 domains of life?
Bacteria, Archea, and Eukarya
Why did the 3 domains of life replace the 5 kingdom system?
The 5 kingdom system is based on classification by observation. The 3 domains of life are based on similarities and differences of molecular information. Therefore, they are more measureable and accurate.
What are the characteristics of ‘Domain Bacteria’?
- Prokaryotic (before nucleus)
- Unicellular
- Cell walls made of peptidoglycan
- small (1-5 micrometers, um)
What are the characteristics of ‘Domain Archaea’?
- Prokaryotic (before nucleus)
- Unicellular
- Cell walls made of pseudopeptidoglycan
- Small (1-5 micrometers, um)
What are the characteristics of ‘Domain Eukarya’?
- Eukaryotic (true nucleus)
- Unicellular & multicellular
- Some have cell walls (cellulose, pectin, chitin)
- large (10-100 micrometers, um)
What are the characteristics of ‘Eukaryotes’?
- DNA, ribosomes, cell membranes, cytosol
- Multiple, linear DNA genome
- membrane bound organelles
What are the characteristics of ‘Prokaryotes’?
- DNA, ribosomes, cell membranes, cytosol
- One curcular DNA genome
What is the ‘SA:V ratio’, what happens when a cell doubles in size, and what are the characteristics of the ‘SA:V ratio’ in the context of small and large cells?
- The SA:V ratio is a ratio measureing a cells surface area to its volume.
- Every time a cell doubles in size, its surface area increases by 4x, and the volume increases by 8x.
- Small cells have a larger SA:V. Large cells have a smaller SA:V.
-Example: x = 6:1, 2x = 3:1, 4x = 1.5:1
Why are prokaryotic cells small?
- A cell’s SA:V effects its ability to transport nutrients to the inner areas of the cell before those inner areas run out of nutrients.
Why are eukaryotic cells big?
- Endomembrane systems store + transport nutrients where they are needed.
- Mitrochondria can make ATP where needed.
What is ‘horizontal gene transfer’ and when does it occur?
- When genes are transfered between organisms
- Occurs when a gene from one species becomes part of another species.
What does endosymbiosis mean? How did it happen?
- Endo = within
- Sym = together
- living together or co-dependant on each other.
Describe the historical formation of Eukaryotes with endosymbiosis in mind.
Start
- Host cell was an archaea-like prokaryote.
- Endosymbiont was a bacteria-like prokaryote really good at aerboic resperation.
- Archaea recieved: ATP
- Bacteria recieved: protection and nutrient source
- Host cell used its excess nutrients to evolve, grow larger, and develope endomembrane system.
End
What is the evidence for the historical formation of Eukaryotes?
- They have their own curcular DNA molecule
- Divide by binary fission
- Have 70S robosomes
- Many other orgnaisms have endosymbiotic relationships
What is the biological definition of ‘Organic’?
- 2 or more C atoms
