Biology

Diffusion

movement of particles from a high concentration to low concentration (Down the gradient)

What is the concentration gradient

when the concentration of particles is not the same throughout

Concentration

the amount of solute in a solution

What is equilibrium

amount of solute is the same throughout

What is semipermeable

membrane that allows certain substances to cross but not the others

Are cell membranes permeable or semi-permeable

semipermeable

what is osmosis

diffusion of water from an area of high to low concentration

What is tonicity

the ability of an extracellular solution to make water move into or out of a cell by osmosis

What is an isotonic solution

concentration of water is the same on both sides of the membrane, amount of water moving into cell the same as moving out

Hypertonic solution

concentration of water is greater inside of the cell. Water leaves the cell and shrivels

Hypotonic solution

concentration of water is greater outside the cell, moving in and cells may burst

what is facilitated diffusion

when molecules cannot diffuse through the cell membrane

Where do facilitated diffusion molecules enter through

they enter though protein channels

it is still diffusion

Does diffusion use energy or no energy

no energy is required for diffusion

What is active transport and is energy required? How do materials pass though the phospholipid bilayer?

Active transport is when material goes from low to high concentration (against the gradient).

needs energy (ATP)

Uses a protein pump to allow materials to pass though

What is endocytosis and what are the different types?

Endocytosis takes materials into the cells by using phagocytosis and pinocytosis

What is phagocytosis

engulfs large materials

What is pinocytosis

takes in liquids

What is receptor mediated endocytosis? Where do molecules bind?

specific molecules ingested into the cells and molecules bind to receptors on the membrane

What is exocytosis?

removing water or waste from the cell

Cell membrane

barrier that regulates material entering and exiting cells

Phospholipid bilayer

two-layer structure with hydrophilic heads and hydrophobic tails

What are hydrophilic heads

polar part of phospholipid that attracts water

Hydrophobic tail

non-polar fatty acid part that repels water

fluid mosaic model

structure is flexible made of many different parts

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