TOPIC 2-Prokaryotic cells and viruses Flashcards
Are prokaryotes single-celled or multicellular?
single-celled
Give an example of a prokaryotic cell
Bacteria (E.coli)
What is the main difference between prokaryotic and eukaryotic cells?
Prokaryotic cells are much smaller as they do not have membrane-bound organelles in their cytoplasm
What does the cytoplasm contain?
ribosomes but they are smaller than the ones in eukaryotic cells
Does the cell surface membrane have the same function as in eukaryotic cells?
yes
What is the cell wall made of?
A polymer called murein
What is murein?
A glycoprotein (a protein with a carbohydrate attached)
What is the function of the capsule and what is made up of?
-Helps to protect the bacteria from attack by cells of the immune system?
-Made up of secreted slime
What are plasmids and what are their functions?
-Small loops of DNA that aren’t part of the main circular DNA molecule
-Plasmids contain genes for things like antibiotic resistance and can be passed between prokaryotes
-(plasmids are not always present in cells but some cells can have several)
Where is the DNA located in prokaryotic cells?
-DNA floats free in the cytoplasm
-Circular DNA, present as one long coiled up strand
-Not attached to any histone proteins
What is the function of the flagellum/flagella?
-Rotates to make the cell move
Are viruses cells?
No, they are acellular, nucleic acids surrounded by a protein
Give some examples of viruses
-HIV
-Influenza
-Rhinoviruses
What are host cells?
All viruses invade and reproduce inside the cells of other organisms
What are the differences between viruses and bacteria?
-No cell surafce membrane
-No cytoplasm
-No ribosomes
-Have a capsid (a protein coat) with attachment proteins
