3.2.1.2 Prokaryotes and viruses Flashcards
what are the key differences between prokaryotes and eukaryotes
- much smaller
- non membrane bound organelles
- a singular circular chromosome vs multiple linear chromosomes
- DNA is not associated with proteins
what do all prokaryotic cells have
- cytoplasm
- cell membrane
- 70S - smaller than eukaryotic
- single circular DNA molecule in cytoplasm
- cell wall made of murein (glycoprotein)
- pili (attachment)
- mesosome
what do some prokaryotic cells have
- one or more plasmids
- capsule surrounding cell (slime capsule)
- one or more flagella
what is a mesosome
an indent in the cell membrane used for ATP production
what are the 2 types of prokaryotes
eubacteria- alive now, archaebacteria- dead now
what are viruses
acellular and non-living, need a host to survive and have no characteristics of living things
what is the process of binary fission
1 - cell replicates the single DNA molecule and plasmids
2 - results in 2 DNA molecules
3 - two copies attach to different parts of the cell membrane
4 - cell ELONGATES and pulls DNA to opposite sides of the cells
5 - septum forms and divides at the cell
6 - plasma membrane and cell wall materials start to accumulate around the septum
7 - the cell pinches and two identical daughter cells are formed
what is a retrovirus
if a virus has RNA
what do viruses have
- attachment proteins - all
- RNA or DNA - all
- lipid envelope
- capsid (protein coat) - all
- reverse transcriptase (makes DNA)
how does HIV work
- reverse transcriptase is used to make DNA from RNA
- DNA joins host cell’s DNA/chromosome
- DNA is used to make HIV RNA copies and capsid
- this is made at host ribosomes
- assembly of new virus particles bud off from membrane
how do viruses reproduce
replicate since they are nonliving
- injection into DNA/RNA of host
- replication of the nucleic acid and viral proteins by the host cell
- assembly of viruses
- release of viruses by budding or cell lysis.
