DLISC1 - week 1 Flashcards
(9 cards)
what are the 7 characteristics of a living organism
- ordered complexity
- cellular organisation
- energy utilisation
- growth, development and reproduction
- homeostasis
- sensitivity
- evolutinary adaptation
three keys reasons why visuses can evolve
- lack of proofreading ability of viral RNA polymerases
- short generation times
- genetic reassortment
what is a virus
a non-cellular and infectious ‘entities’
use the host cells energy and biosynthetic machinery to make copies of itsself
does not fit the defintion os living things (7)
structure of a virus
alternate between 2 states: intracellular (in host) and extracellular (virion)
basic structure: nucleic acid core, protein coat surrounding nucleic acid core (capsid) and no cytoplasm
most DNA viruses are ds
all RNA viruses are ss
explain the steps of vral replication
- attachemnt to host
- entry - viruses penetrate to cell membrane, uncoating of genome, releasing nucleic acid into cell
- synthesis - viral ‘genes’ expresssed and replicated using host machinery
- assembly - nucleic acid packaged into virions through self-assembly
- release - of progeny virions (host cell may be destroyed in the process)
what is protein trafficking
process by which proteins are transported from their sites of synthesis to where they are needed
describe the process of protein trafficking
- Protein synthesis beings when a gene on DNA produces messenger RNA (mRNA), the temple from protein synthesis
- The mRNA leaves the nucleus and attaches to a free ribosome in the cytoplasm, or a fixed ribosomes on the RER
- Proteins constructed on free ribosomes are released into the cytosol for use within the cell
- Protein synthesis on fixed ribosomes occurs at the RER. The newly synthesised protein folds into its 3-dimensional shape
5.The proteins are then modified within the ER. Regions of the ER then bud off forming transport vesicles containing modified proteins and glycoproteins - The transport vesicles carry the proteins and glycoproteins generated in the ER toward the Golgi apparatus.
- The transport vesicles then fuse to create the forming cis face (“receiving side”) of the Golgi apparatus
- Multiple transport vesicle combine to form cisternae on the cis face. Further protein and glycoprotein modification and packaging occur as the cisternae move toward the maturing (trans) face. Small transport vesicles return resident Golgi proteins to the forming cis face re use.
- The maturing trans face (“shipping side”) generates vesicles that carry modified proteins away from the Golgi apparatus. One type of vesicle becomes a lysosome, which contains digestive enzymes
- Two other types of vesicles proceed to the plasma membrane: secretory and membrane renewal. Secretory vesicles fuse with the plasma membrane and empty their products outside the cell by exocytosis. Membrane renewal vesicles add new lipids and proteins to the plasma membrane
what is the mitochondria
tubular organelles surrounded by a double membrane
what is the cytoskeleton
cytoplasm or eukaryotes contains network or protein fibres, constantly assembling and disassembling, it support the cell shape.
