Cell Biology Exam 1 Wormington exam with
answers
What do all cells have in common? - CORRECT ANSWERS
✔✔plasma membrane
genome
information transfer
energy utilization
How did cells evolve? - CORRECT ANSWERS ✔✔self
replicating rna catalyzes reactions and encode proteins
proteins facilitate accuracy of replication and translation
dna replaces rna genome because it is more stable and
better at maintaining genetic info
proteins govern transportation across plasma membrane
Features that define prokaryotes: - CORRECT ANSWERS
✔✔single compartment
unicellular
adapted for metabolic and environmental diversity
,Mesophiles - CORRECT ANSWERS ✔✔largest group and
are mostly eubacteria
extremophiles - CORRECT ANSWERS ✔✔ie psychrophiles
(polar ice caps) or thermophiles (hot springs)
Features of Eukaryotes: - CORRECT ANSWERS
✔✔unicellular but primarily multicellular
highly compartmentalized
relatively limited metabolic and environmental
adaptability
primarily adapted for specialized or differentiated
functions
Evidence for Endosymbiotic Theory: - CORRECT ANSWERS
✔✔chlorplasts and mitochondria retain own genomes
mitochondria and chloroplasts rna polymerases and
ribsomes structurally resemble those in prokaryotes
mitochondria deviate from otherwise universal genetic
code used for nuclear encoded genes
chloroplasts divide by fission like bacteria
But what does the endosymbiotic theory not explain? -
CORRECT ANSWERS ✔✔only 10-20% of the mitochondrial
proteome display clear alpha-proteobacterial ancestry;
, thereby, implying horizontal gene transfer between
prokaryotes and eukaryotes
How did multicellularity evolve? - CORRECT ANSWERS
✔✔A mutation in a single gene caused cells to stick
together.
1. Sticking together: allowed cells to stick together after
division
2. Early embryogenesis: cells linked by cytoplasmic
bridges to form bowl shaped structure
3. Successful swimmers: flagella that beat in opposite
directions
4. Becoming one: bridges are permanent forming
extracellular matrices and gap junctions
5. Multiple cell types: due to evolution of asymmetric cell
division (division of labor)
Is multicellularity reversible? - CORRECT ANSWERS
✔✔Yes, through use of antibiotics. The contaminant, RIF-1
on a protein caused multicellularity. If RIF-1 is eliminated,
then unicellularity is possible. Cancer cells often revert
back to UCO mechanisms. ANCIENT
Why are model organisms generally applicable to
understanding human cell biology? - CORRECT ANSWERS
answers
What do all cells have in common? - CORRECT ANSWERS
✔✔plasma membrane
genome
information transfer
energy utilization
How did cells evolve? - CORRECT ANSWERS ✔✔self
replicating rna catalyzes reactions and encode proteins
proteins facilitate accuracy of replication and translation
dna replaces rna genome because it is more stable and
better at maintaining genetic info
proteins govern transportation across plasma membrane
Features that define prokaryotes: - CORRECT ANSWERS
✔✔single compartment
unicellular
adapted for metabolic and environmental diversity
,Mesophiles - CORRECT ANSWERS ✔✔largest group and
are mostly eubacteria
extremophiles - CORRECT ANSWERS ✔✔ie psychrophiles
(polar ice caps) or thermophiles (hot springs)
Features of Eukaryotes: - CORRECT ANSWERS
✔✔unicellular but primarily multicellular
highly compartmentalized
relatively limited metabolic and environmental
adaptability
primarily adapted for specialized or differentiated
functions
Evidence for Endosymbiotic Theory: - CORRECT ANSWERS
✔✔chlorplasts and mitochondria retain own genomes
mitochondria and chloroplasts rna polymerases and
ribsomes structurally resemble those in prokaryotes
mitochondria deviate from otherwise universal genetic
code used for nuclear encoded genes
chloroplasts divide by fission like bacteria
But what does the endosymbiotic theory not explain? -
CORRECT ANSWERS ✔✔only 10-20% of the mitochondrial
proteome display clear alpha-proteobacterial ancestry;
, thereby, implying horizontal gene transfer between
prokaryotes and eukaryotes
How did multicellularity evolve? - CORRECT ANSWERS
✔✔A mutation in a single gene caused cells to stick
together.
1. Sticking together: allowed cells to stick together after
division
2. Early embryogenesis: cells linked by cytoplasmic
bridges to form bowl shaped structure
3. Successful swimmers: flagella that beat in opposite
directions
4. Becoming one: bridges are permanent forming
extracellular matrices and gap junctions
5. Multiple cell types: due to evolution of asymmetric cell
division (division of labor)
Is multicellularity reversible? - CORRECT ANSWERS
✔✔Yes, through use of antibiotics. The contaminant, RIF-1
on a protein caused multicellularity. If RIF-1 is eliminated,
then unicellularity is possible. Cancer cells often revert
back to UCO mechanisms. ANCIENT
Why are model organisms generally applicable to
understanding human cell biology? - CORRECT ANSWERS
