Prokaryotic Cells Flashcards
What are the main differences between eukaryotic organisms and prokaryotic organisms?
- Eukaryotic cells are larger and have a nucleus bounded by a nuclear membrane.
- Prokaryotic cells are smaller and have no nucleus or nuclear envelope.
What are some features of the cytoplasm of a prokaryotic cell?
- Has no membrane bound organelles
* It has ribosomes that are smaller than those in eukaryotic cells.
What is the flagellum?
Long hair like structure that rotates allowing the prokaryotic cell to move.
What are some features of the DNA of a prokaryotic cell?
- It doesn’t have a nucleus.
- DNA floats free in the cytoplasm present as a long coiled up strand.
- Not attached to any histone proteins.
What are plasmids?
• Plasmids are small loops of DNA that aren’t a part of the main DNA molecule.
What is the purpose of plasmids?
• Plasmids contain genes for things like anti-biotic resistance, and this can be passed between prokaryotes.
What are bacterial cells walls made up of?
Murein.
What is murein?
A polymer of polysaccharides and peptides; murein is glycoprotein.
How do bacterial cells protect themselves?
- Having a cell wall.
* Secreting a capsule of mucilaginous slime around the wall.
What is the purpose of the cell wall?
The cell wall supports the cell and prevents it from changing shape, it is made up of a polymer called murein.
How does the nucleus differ from prokaryotic cells to eukaryotic cells?
Prokaryotic Cells:
• No true nucleus, only an area where DNA is found.
Eukaryotic Cells:
• Distinct nucleus, with a nuclear envelope.
How does the DNA differ in eukaryotic cells and prokaryotic cells?
Prokaryotic Cells:
• DNA is not associated with proteins.
• DNA may be in the form circular strands called plasmids.
Eukaryotic Cells:
• DNA is associated with proteins called histones.
• There are no plasmids and DNA is linear.
How do chloroplasts differ between prokaryotic cells and eukaryotic cells?
Eukaryotic Cells:
• Chloroplasts present in plants and algae.
Prokaryotic Cells:
• No Chloroplasts, only bacterial chlorophyll associated with cell surface membrane in some bacteria.
How do ribosomes differ between prokaryotic cells and eukaryotic cells?
Prokaryotic Cells:
• Ribosomes are smaller
Eukaryotic Cells:
• Ribosomes are larger
How do the cell walls differ between prokaryotic cells and eukaryotic cells?
Eukaryotic cells:
• Cell wall made of murein
Prokaryotic Cells:
• Cell wall is mostly made of cellulose ( chitin in fungi ).
How does the capsule differ between prokaryotic cells and eukaryotic cells?
Prokaryotic Cells:
• Have an outer mucilaginous layer called a capsule.
Eukaryotic Cells:
• No Capsules
What are viruses?
Viruses are acellular non living particles.
What are viruses made up of?
- A core of genetic material ( DNA or RNA ).
- A protein coat around the core called the capsid.
- Attachment proteins that stick out from the edge of the capsid.
What is the capsid?
The Capsid is the protein coat which surrounds the nucleic acid.
What is the purpose of the attachment proteins?
Allows the virus to identify and attach onto a host cell.
Are viruses living?
No.
How do prokaryotic cells replicate?
Binary fission:
• Circular DNA and plasmids replicate. The main DNA loop is only replicated once, but the plasmids can be replicated many times.
• Cell gets bigger and the DNA loops move to opposite poles of the cell.
• The cytoplasm begins to divide ( and a new cell wall begins to form ).
• Cytoplasm divides and two daughter cells are produced, each daughter cell has one copy of the circular DNA, but can have a variable number of copies of plasmids.
How do viruses replicate?
- Viruses use their attachment proteins to bind to complementary receptor proteins on the surface of host cells.
- Different viruses have different attachment proteins and therefore require different receptor proteins on host cells. As viruses can only infect one type of cell.
- Viruses inject their DNA, or RNA into the host cells, the hijacked cell uses its own organelles to replicate the viral particles.
