Flashcards in 01_Intro to Cell Bio Deck (8)
What are three components of cell theory?
1) All organisms are composed of one or more cells.
2) Cells are the structural units of life.
3) Cells arise from pre-existing cells through the process of cell division.
What are the three domains of life? Which are prokaryotes?
Eukaryotes, Archaea, Bacteria; the latter two are prokaryotes.
Which came first: eukaryotic cells or prokaryotic cells?
Describe endosymbiotic theory in 1 sentence.
Prokaryotic cells arose first, and organelles in eukaryotic cells (mitochondria & chloroplasts) evolved from smaller prokaryotic cells.
What evidence is there in support of endosymbiotic theory? (6 points)
- Eukaryotic cell organelles (mitochondria & chloroplasts) contain their own DNA.
- Ribosomal RNA sequences in eukaryotes are highly conserved, and resemble that of prokaryotic cells.
- Organelles duplicate independent of the nucleus.
- There is an absence of any intermediary evolutionary step containing eukaryotic cells with organelles.
- Mitochondria/chloroplasts possess a DOUBLE lipid bilayer (inner membrane is prokaryote-like; outer membrane eukaryote-like -- BUT this simplification is controversial)
- There exist many symbiotic relationships between organisms.
What is the proposed origin for the mitochondrion, chloroplast, and the "parent" cell?
aerobic bacterium, photosynthetic cyanobacterium, and anaerobic heteretrophic prokaryote (respectively).
What is the point of controversy in endosymbiotic theory?
Appearance of the nuclear envelope and the ER