movement in and out of the cell (plasma membrane) Flashcards
The role of the plasma membrane is to
- separate the cell from the nonliving environment
- maintain homeotasis
Homeostasis
is the constant maintenance of an environment
How is the plasma membrane selectively permeable?
It allows some molecules in and out freely and prevents other from entering
What molecules are able to easily move through the lipid bilayer?
- Small noncharged polar molecules like water
- gases
What molecules cannot move easily through the lipid bilayer?
- Ions or charged polar molecules
- large macromolecules
Passive transport is…. examples of passive transport is
Passive transport is when a molecule moves through the bilayer without using energy
Diffusion: High concentration to low concentration
Facilitated diffusion: when molecules travel through a channel or carrier moving against the concentration gradient low to high concentration
Aquaporins
allows water to move through protein channels through facilitated diffusion
osmosis:
water moves from region with lower Solute to higher solute
or
water moves from high concentration to low concentration
Primary active transport
- ## uses energy in the form of ATP to go against the concentration gradient
Secondary active transport
- Cells pump protons through harvesting ATP- ADP
- creates an electrochemical gradient
- antiporter uses energy from electrochemical gradient to move large molecules
A chemical gradient requires
- a charge
- chemical components
hypertonic
low water concentration
hypotonic
High concentration of water
Isotonic
Water moves freely and equally
What is the purpose of a contractile vacuole?
collects excess water in the cell and pumps it out of it
