Cell Membrane And Transport Processes Flashcards
(37 cards)
Phospholipid bilayer
Nonpolar fatty acid tails turn inside. Polar phosphate head turns outside. = forms flexible structure as a boundary
Cell membrane
9 things: Phospholipid bilayer Outside of cell Inside of cell Cholesterol Polysaccharide Glycolipid Glycoprotein Integral protein Peripheral protein
Proteins
Can be integral proteins or peripheral proteins. Act as enzymes, receptors, transport and binding molecules
Carbohydrates
Identification tags outside of the cell membrane(glycolipid and glycoproteins).
Cholesterol
Helps stabilize the membrane by making it more solid. - animal cells
Functions of the cell membrane:
- surrounds the cell
- regulate the transport of molecules in and out of the cell–semipermeable
- immune response
- attaches cells to other cells or surfaces
- fluid mosaic model.
Selective permeability
Cell membranes control what goes in and out of the cell. It allows som substances to cross more easily than others.
Passive transport processes
Transport means the movement of molecules from one side of the cell membrane to the other.
Transport is influenced by:
- the size of substances
- the polarity of substances
- the concentration of substances
- the permeability of the cell membrane
Passive transport requires:
No energy from the cell, the energy comes from the difference in concentration not ATP(energy from the cell). Moves smaller substances from the higher concentration area to the lower concentration area. Important in transporting O2, CO2, water, and small molecules.
Diffusion
Moving substances within the cell and smaller nonpolar molecules across then phospholipid bilayer.
Osmosis
The movement of water across the cell membrane by using phosplipid bilayer or transport proteins.
Tonicity
Describes the tendency of a cell in a given solution to loose of gain water. Isotonic, hypertonic, and hypotonic.
5 macromolecules in the cell membrane are…
Phospholipid
Carbohydrates
Proteins (integral and peripheral)
Cholesterol
When does the molecular movement stop?
Equilibrium
Why do cells need transport processes? What is the role of the cell membrane in these?
Cells need transport processes to receive or get rid of materials. The cell membrane only allows certain particles into of out of the cell.
Isotonic solutions
When cells are put into solutions that have equivalent salt concentration, visible osmosis does not take place.
Hypotonic solutions
Cells in very dilute solutions will take in water and eventually burst(animal cells not plants cause plants have cell walls).
Hypertonic solutions
Cells in very concentrated solutions will lose water and shrink. Plants spells plasmolize in hypotonic solutions (lose water and move away from the cell wall) and become turgid(plumps) in hypotonic solutions.
Facilitated diffusion
A special type of diffusion, in which the transported molecules are moved by the help of a transport protein.
Active transport
Transport processes that move substances from lower concentration to higher concentration areas by using energy(ATP). Transport proteins are always required.
NAK ion pump
3 sodium ions move out of the ell with help of a transport protein , while 2 potassium ions move into the cell. goes against concentration gradient.
H+ ion pump
Moves hydrogen ions (protons) from low to high concentration areas by using energy from the cell(ATP). Goes against concentration gradient.
Bulk transport
Transport large molecules through the cell membrane by using vesicles.