3.6- PROKARYOTIC CELLS AND VIRUSES Flashcards
What are the two main types of cells?
eukaryotic cells and prokaryotic cells
What is the size of eukaryotic cells and what do they have?
larger + have nucleus bounded by nuclear membranes (nuclear envelope)
What is the size of prokaryotic cells and what do they not have?
smaller + have no nucleus or nuclear envelope
Why do bacteria occur in every habitat in the world?
versatile, adaptable + very successful
What is much of the success of bacteria due to?
their small size, normally ranging from 0.1 to 1.0μm in length
What is the cellular structure of bacteria like?
relatively simple
What do all bacteria possess?
cell wall
What is the cell wall of bacteria made up?
murein
What is murein?
polymer of polysaccharides + peptides
How do many bacteria further protect themselves?
by secreting a capsule of mucilaginous slime around this wall
What is within the cell wall of a bacteria?
cell-surface membrane
What types of ribosomes are in the cytoplasm of a bacteria cell?
70S ribosomes
What is the difference between 70S and 80S ribosomes?
70S smaller
What does bacteria store food reserves as? (2)
glycogen granules + oil droplets
What is the genetic material in bacteria in the form of?
circular strands of DNA
What is a form of genetic material that is separate from smaller circular pieces of DNA?
plasmids
What can plasmids do?
reproduce themselves
What can plasmids give bacteria?
resistance to harmful chemicals e.g. antibiotics
What are plasmids used extensively as?
vectors (carriers of genetic information) in genetic engineering
Is DNA associated with proteins in prokaryotic cells?
no
Is DNA associated with proteins in eukaryotic cells?
yes- proteins called histones
What is the role of the capsule in a bacteria?
protects bacterium from other cells + helps groups of bacteria to stick together for further protection
What is the flagellum in bacteria used for?
locomotion (only certain species)
How thick is the cell wall of a bacteria?
10-80nm thick
What are viruses?
acellular, non-living particles
Range of size for viruses
20-300 nm
What do viruses contain as genetic material?
nucleic acids such as RNA or DNA
Where can viruses multiply only?
inside living host cells
Where is the nucleic acid of viruses enclosed within?
within protein coat called capsid
Example of virus that that is surrounded by a lipid envelope?
HIV
What does the lipid envelope, or if this is not present, capsid, what do they have?
attachment proteins
What are the attachment proteins of viruses essential for?
to allow virus to identify + attach to a host cell
