Transport of materials across plasma membrane Flashcards
What are the two types of passive transport?
Simple diffusion and facilitated diffusion
Does passive transport require any energy to occur?
No, it doesn’t
Give three examples of molecules that participate in simple diffusion
- O2
- CO2
- Non-polar molecules
Give three examples of molecules that participate in facilitated diffusion
- ionic (charged) polar molecules
- water
- glucose
Which transport moves molecules from a low concentration outside of cell to a high concentration inside of cell?
Active transport
Which transport moves molecules from a high concentration outside of cell to a low concentration inside of cell?
Passive transport
Which type of transport requires energy?
Active transport
How does active transport get larger ions/metabolites into a cell?
Using carrier proteins and cell channels
Define diffusion
the net movement of molecules down a concentration gradient, allowing small molecules to cross the plasma membrane
What molecule defuses through a plasma membrane through osmosis?
Water
What does it mean if the concentration of solutions on both sides of the membrane are equal?
the solutions are isotonic
Osmosis Definition:
net diffusion of water across a membrane towards a HIGHER solute concentration
What is a hydration shell?
water molecules that surround the charged solute molecules
In osmosis, would the side with the higher or lower solute concentration contain more free water molecules?
lower solute concentration has MORE free water molecules, as the higher side has more water molecules in HYDRATION SHELLS
In osmosis, what is a hypertonic solution?
a solution with a HIGHER solute concentration
In osmosis, what is a hypotonic solution?
a solution with a LOWER solute concentration
What are aquaporins and what do they do?
channels in the cell membrane which regulate water in the cell; facilitate osmosis
What stops ions entering an aquaporin channel?
a charged section in the middle of the channel
What happens to red blood cells in hypertonic solution?
Become shrivelled as water moves out of cell
What happens to red blood cells in hypotonic solution?
Become swollen and will eventually burst as water moves into the cell
Which solution do animal cells need to be in? Hypertonic, Isotonic or Hypotonic?
Isotonic
What is active transport?
Active transport uses energy (ATP) to move materials against a concentration gradient
What are the three carrier proteins used in active transport?
Uniporters, symporters and Antiporters.
What is cotransport?
When both molecules are moving in the same direction across the membrane and the transporter is a symporter.
What is counter-transport?
the inwards movement of Na+ is coupled with outward movement of another substance, like Ca2+ or H+
What is endocytosis?
a process which allows bulk transport of molecules INTO the cell
What is exocytosis?
Removes substances out of cell in bulk
Name 3 examples of endocytosis.
Phagocytosis; Pinocytosis and Receptor-mediated endocytosis
