chapter 4 Flashcards
Discuss the cell theory
the cell theory is based on 3 main principles: - all living organisms are composed of one or more cells, the life processes of heredity and metabolism occur within these - cells are the smallest living things, the basic unit of organisation in organisms - cells arise by division of a previously existing cell
factors that affect rate of diffusion of cells
- surface area available for diffusion . 2. temperature 3. concentration gradient of diffusing substance 4. distance over which diffusion must occur
Name a factor that affects the size of a cell
the diffusion of substances in and out of the cell
describe the surface area to volume ratio
as the cell size increases its volume increases more rapidly than its surface area
what part of the cell plays a key role in controlling the functioning of the cell and why
the cell membrane ,as it provides the only opportunity for interaction with the environment
disadvantages for larger cells
- higher production of wastes - higher energy requirements -the need to produce more macro- molecules
structural features that all cells share:
- centrally located genetic material - the cytoplasm - the plasma membrane - ribosome
nucleoid
where the genetic material in prokaryotic cells is found, is not segregated from the cells interior membrane.
nuclear envelope
double membrane structure that encloses the genetic material in eukaryotic cells
organelle
a discrete macromolecular structure within the cytoplasm with a specific function
plasma membrane
a layer that separates the contents of a cell from its surroundings. gets its structure from the tail ti tail packing of phospholipids
describe prokaryotes
- enclosed by a rigid cell wall. - contains a cytoplasm within a plasma membrane - have no interior compartments ( ribosomes)
the to main domains of prokaryotes
archaea and bacteria
peptidoglycan
cell wall of bacterial cells consisting of carbohydrate matrix cross linked by short polypeptide bonds
