Chapter4 Flashcards
cells are the
basic unit of life
three basic features of cells
- compartmentalization -allows for specilization
- self assembly and homeostatsis
- replication- every cell is formed from a pre exisiting cell
in multicellular organisms
specialization occurs between cells
cell size
most cells are 1-100 um in diameter
1 um= 0.000 001 m
eukarotic
organelles surrounded by a membrane
prokaryotic
no organelles surrounded by membranes
what regulates the size of cells
minimum size- limited by ability to pack structural components into the cell
viruses are not living things: they are too small to carry out homeostasis
what regulates the size of cells 2
maximum size - limited by the ratio of surface area to volume
if cells have a cube shape
volume= L3
surface area= L2 x 6
in multicellular organisms most cell to cell connections allow for
the passage of material
animal cells include
tight junctions prevent fluid from moving between cells tight junctions anchoring junction gap junction plasma membrane of adjacent cells
multi celled organisms need
structures that maximize surface area
components of cells- membranes (sheet like structures)
- compartmentalization
- selective passage of material (semi permeable)
- sites of chemical reactions
- receptors for cell recognition
cytoplasm
fluid medium and organelles
cytoskeleton
provides structure controls movement
