A2 (origin of cells, cell structure, viruses) Flashcards
What is the cell theory
All living things are composed of cells; cells are the basic units of life; cells come from pre-existing cells.
what is the endosymbiotic theory
Mitochondria and chloroplasts have bacterial origins.
Discuss the evidence supporting the endosymbiotic theory. How does this theory explain the presence of mitochondria and chloroplasts in eukaryotic cells?
Bacteria, a prokaryote, has circular DNA, as do mitochondria and chloroplasts.
This provides support for the Endosymbiotic Theory,
which states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote).
Evaluate the statement: “All cells come from pre-existing cells.” Provide evidence supporting this statement and discuss its implications for the study of cell biology.
-observations of cell division,
-the lack of spontaneous generation in controlled experiments,
-the presence of structures like the mitotic spindle during cell division
Discuss the role of endosymbiosis in the evolution of eukaryotic cells. What advantages might a eukaryotic cell gain through the acquisition of mitochondria?
Endosymbiosis suggests that eukaryotic cells engulfed free-living prokaryotes, forming a mutualistic relationship.
-Mitochondria, with bacterial ancestry, provide ATP through respiration, benefiting the host cell.
Compare and contrast prokaryotic and eukaryotic cells, highlighting the advantages and disadvantages of each cell type.
Prokaryotes lack a nucleus and membrane-bound organelles; eukaryotes have a true nucleus and organelles.
Prokaryotes: chances of the damaging the genetic material are greater.
eukaryotes: more complex, therefore, requires more time to complete any mechanism related to reproduction compared to the prokaryotic cell.
Cell Structure: Cell Membrane
Phospholipid bilayer, selective permeability.
Explain the significance of the fluid mosaic model in understanding the structure and function of cell membranes. How does membrane fluidity impact cellular processes?
describes the dynamic nature of cell membranes.
Phospholipids and proteins are free to move laterally, allowing flexibility.
Membrane fluidity impacts processes such as cell signaling and endocytosis.
Viruses.
Structure:
Genetic material (DNA or RNA) surrounded by a protein coat (capsid).
Viruses.
Non-living. How does it replicate?
Depend on host cells for replication.
Evaluate the statement: “Viruses are not considered living organisms.” Support your argument with key characteristics of living organisms and the structure and behavior of viruses.
Viruses have the following non-living characteristics:
-They don’t have cytoplasm or cellular organelles, and they’re not cells.
-Within the infected host cell, new viruses are produced and assembled.
-The viruses are inactive outside of the host.
-They are unable to reproduce or develop outside of the host cell.
Compare and contrast the replication strategies of DNA and RNA viruses. Include the terms reverse transcriptase and viral envelope in your discussion.
-DNA Viruses: Replicate in the host cell nucleus.
RNA Viruses: Replicate in the host cell cytoplasm.
Envelope: Viruses may acquire a lipid envelope from host membranes.
Discuss the potential applications and challenges of using viruses in gene therapy.
Viruses in gene therapy:
can be modified to deliver therapeutic genes.
Challenges: immune responses, potential side effects, and ethical considerations regarding genetic manipulation.
