7.3 Slides Flashcards
The cell membrane is the boundary between:
the cell and it’s environment
What does the cell membrane allow the cell to do?
1) allows the cell to be distinctly different and separate from its environment
2) allows nutrients and water into the cell
3) allows the cell to get rid of waste materials produced by the cell
how do we get rid of cellular waste?
waste goes out through plasma membrane into the blood, then goes through special organs then gets expelled (ex: co2 carried by red blood cells, throuhg lungs and breathed out, kidney’s filter blood to get urine and then it can be expelled)
2 Negative results from malfunction of cell membrane:
1) Starvation- lack of nutrients results in poor nutrition and poor cellular health
2) Poisoning- if the cell can not rid itself of waste materials, the cell will ultimately die of poisoning from its own waste
cells must keep the:
internal conditions of a cell relatively constant- do this is 2 ways, one is passive (does not require energy from the cell)
Diffusion is a type of:
passive transport
Diffusion is:
the random movemnt of substances in a fluid from an area of higher concentration to a ower concentration until dynamic equilibrium is acheived
Facilitated Diffusion:cell membrane allow small particles to pass through easily because of their:
small size and the fact that they have no charge
Many ions (charged molecuels) like CL- and others like glucose seem to pass through the cell membrane:
more quickly than they should, assisted by facilitated diffusion
proteins in the cell membrane acr as:
carriers or channels
how many differnet proteins are embedded in the plasma membrane that assist nutrients to enter or leave the cell?
hundreds
the movement of materials is much faster in:
facilitated diffusion than simple diffusion, but still no energy is required
Why does water have a hard time crossing the cell membrane?
the hydrophobic lipid tails of the phospolipid bilayer
Aquaporins are sturctures in the cell membrane that
that facilitate movement of water through the membrane through a process known as osmosis
Osmosis is the:
passive movement of water across a selectively permeable membrane from high to low concentration until dynamic equilibrium is achieved
Isotonic solutions occur when:
when dynamic equilibrium is acheived with an equal amount of substance entering and leaving the cell
hypotonic solutions:
when cells take in more substance than they release
hypertonic solutions:
when cells release more substance than is taken in
Active transport involves movement of substnace:
against a concentration gradient (from lower to higher)
in active transport:
cellular energy is required
example of active transport within the animal body system:
sodium potassium pump
