What are cells? Flashcards
what are the three layers of a virus?
-lots of proteins on the surface
-some viruses have a membrane
-inside the virus are more proteins and nucleic acid (DNA or RNA)
what do viruses need to be considered “alive”?
in contact with a cell
how do viruses use cells to cause disease? (5 points)
-viruses bind to a molecule on the surface of a cell
-trick the cell into thinking it is something the cell needs
-cell take virus in
-virus then hijacks cell and uses the resources to produce more viruses
-new viruses exit and infect other cells
what are the three things Sir Paul Nurses thinks makes something alive?
-evolution through natural selection
-seperated from their environment by a boundary (e.g. membrane)
-metabolically active and use their metabolism to maintain themselves
do Sir Paul Nurses conditions mean viruses are alive or not?
Viruses cycle between alive (when in a cell) and not-alive (when by themselves)
what are the two main types of cell?
prokaryotic and eukaryotic
what are the three key features of prokarotic cells?
-small and simple
-don’t have much internal structure
-don’t have a nucleus
what are the three main features of a eukaryotic cell?
-larger and more complex
-membrane bound (organised) organelles
-do have a nucleus
5 common features of all cells?
-surrounded by a membrane made of lipids
-can sense and respond to their environment
-contain DNA or RNA
-use building block (such as amino acids, proteins, carbohydrates, ect.)
- highly dynamic and constantly changing
why do viruses need larger cells in order to replicate?
they are too small to function on their own
roughly how much larger is the volume of a eukaryotic cell than a prokaryotic cell?
x1000
what issue do the larger eukaryotic cells face and how do they deal with it?
diffusion takes much longer when the cell is larger
so eukaryotic cells compartmentalise to allow cells to work more efficiently
what is compartmentalisation?
the separation of the cell interior in distinct compartments with specific local conditions that allow the simultaneous occurrence of diverse metabolic reactions and processes
what opportunities does compartmentalisation provide to cells?
-can change the number and type of organelles they produce
-allows cells to specialise
how many genes does a mycoplasma have?
~382
