ultrastructure of prokaryotic cells Flashcards
How does the structure of prokaryotic cells differ from eukaryotic cells?
Prokaryotic cells do not have membrane-bound organelles or a nucleus. Their DNA is free in the cytoplasm.
What is the function of the plasma membrane in prokaryotic cells?
It controls the movement of substances into and out of the cell.
What is a plasmid?
A plasmid is a small loop of DNA that is separate from the main circular DNA.
What is a flagellum?
A flagellum is a long, hair-like structure that rotates to help the cell move.
What are pili, and what is their function?
Pili are short, hair-like structures that help prokaryotes stick to other cells and can be involved in the transfer of genetic material.
How is the DNA in prokaryotic cells different from eukaryotic cells?
Prokaryotic DNA is circular and floats freely in the cytoplasm. It is not attached to histone proteins.
What are mesosomes, and what is their possible function?
Mesosomes are inward folds in the plasma membrane.
How small are prokaryotic cells?
They have diameters between 0.5 and 5 µm.
What is peptidoglycan, and where is it found?
Peptidoglycan is a combination of polysaccharide and polypeptide, found in the prokaryotic cell wall.
Describe three structural differences between prokaryotic and eukaryotic cells.
Prokaryotic cells:
-lack a nucleus and membrane-bound organelles,
-have smaller ribosomes (70S),
-and possess a cell wall containing murein (peptidoglycan). In contrast, eukaryotic cells have a nucleus, membrane-bound organelles, larger ribosomes (80S), and, in plant cells, a cell wall made of cellulose.
How does the size of ribosomes differ between prokaryotic and eukaryotic cells?
Prokaryotic cells have smaller ribosomes (70S) compared to eukaryotic cells, which have larger ribosomes (80S).
