Passive and Active Transport
The bursting of cells is called
cytolysis.
The pressure that water molecules exert against a cell wall is called
turgor pressure
When water enters the cell, it creates pressure. This pressure is called
turgor pressure
A relatively low solute concentration is called
hypotonic
Net movement of water across a cell membrane occurs from a _______ solution to a _______ solution.
hypotonic hypertonic
Most of the time, the environment that plant cells live in is an
hypotonic environment.
pinocytosis
involves the ingestion of fluids and solutes
phagocytosis
involves the ingestion of of large particles and whole cells
In an _____________ the concentration of solutes outside and inside the cell are equal.
isotonic environment
endocytosis
the process by which cells ingest external fluids, macromolecules, and large particles
exocytosis
vesicles that remove large particles out of the cell
The diffusion of __________ through the cell membranes is called osmosis.
water
Explain how substances cross the cell membrane through facilitated diffusion
Carrier proteins embedded in the cell membrane lightly bind to these substances and then change shape to allow the substance to move across the cell membrane.
Distinguish between diffusion and osmosis
Diffusion is the movement of particles from an area of high concentration to an area of low concentration. While osmosis is the movement of water molecules from and area high concentration to an area of low concentration.
Compare and contrast hypotonic, hypertonic, and isotonic environments
Hypotonic: more water less solute, plasmolysis Hypertonic: less water more solute, shrivels up, plasmolysis Isotonic: equal amounts of solute and water,
Identify how a cell reacts in one of the above environments
In an hypertonic environment the water wants to go into the cell and therefore the water makes the egg swell up.
Which type of molecule forms a bilayer within a cell membrane?
Phospholipids
Define a concentration gradient
The difference in the concentration of molecules across a space
_______ is the most common solvent in cells.
Water
vesicles
cell membrane that pinches off around external materials and becomes an organelle
A ____________ ____________ is the concentration difference across space.
concentration gradient
The process of diffusion requires
concentration gradient/the movement of molecules from an area of high concentration to an area of low concentration.
A structure that can move excess water out of a unicellular organism is a
contractile vacuole
The movement of molecules from an area of higher concentration to an area of lower concentration is called
diffusion.
Molecules always diffuse ________ their concentration gradient.
down
A cell does not expend ______ when diffusion takes place.
energy
If the molecular concentration of a substance is the same throughout space, the substance is in
equilibrium.
Molecules that are too large to be moved across a cell membrane can be removed from the cell by
exocytosis
Glucose molecules cross the cell membrane by means of
facilitated diffusion
A relatively high solute concentration is called
hypertonic
Plasmolysis of a human red blood cell would occur if the cell were in a(n)
hypertonic environment.
All forms of passive transport depend on the __________ of molecules.
movement
A type of transport in which water moves across and down its concentration gradient is called
osmosis
The diffusion of water across a membrane is called
osmosis
The movement of some substances, without any input of energy by the cell, is called
passive transport.
The uptake of large particles is called
phagocytosis
The shrinking of cells is called
plasmolysis
A cell membrane is said to be _________ _________because it allows the passage of some solutes and not others through.
selectively permeable
A ____________________________ only allows certain molecules to pass thorough.
selectively permeable membrane
Sodium potassium pump
the carrier protein in animal cells that maintain a higher concentration of Na+ ions outside the cell and higher concentration of K+ ions inside the cell
active transport
the movement of materials from an area of low concentration to high concentration
