PLASMA MEMBRANE Flashcards
(25 cards)
What is the function of the Cell Membrane?
It forms the BOUNDARY of a cell.
It MAINTAINS the INTERNAL ENVIRONMENT of the cell by CONTROLLING THE MOVEMENT OF SUBSTANCES into and out of the cell.
What is the FLUID MOSAIC MODEL composed of?
THE FLUID MOSAIC MODEL OF THE CELL MEMBRANE is composed of:
PHOSPHOLIPID BI-LAYER
PROTEINS
CARBOHYDRATE CHAINS
What type of cells are surrounded by a Cell/Plasma Membrane?
ALL CELLS (both PROKARYOTIC and EUKARYOTIC) are surrounded by a cellular membrane.
What is the role of the PHOSPHOLIPIDS and PROTEINS in the Cell Membrane?
The PHOSPHOLIPID and PROTEIN parts of the membrane allow the passage of substances into and out of the cell
What is the role of the CARBOHYDRATE CHAINS in the Cell Membrane?
CARBOHYDRATE CHAINS are involved in CELL RECOGNITION
A PROTEIN attached to a CARBOHYDRATE CHAIN is called a ___________
GLYCOPROTEIN
The PHOSPHATE HEADS of the PHOSPHOLIPIDS ARE _______________ and ___________
HYDROPHILIC (loves water) and LIPOPHOBIC (hates fat)
The LIPID TAILS of the PHOSPHOLIPIDS are ________ and _________
HYDROPHOBIC (hate water) and LIPOPHILIC (love fat)
Whether or not a substance can PASS THROUGH THE CELL MEMBRANE depends on:
THE SIZE OF PARTICLES: particles that are smaller can pass through the membrane more readily, as can large charged molecules.
THE SOLUBILITY OF PARTICLES IN WATER: substances which don’t dissolve in water can’t pass through the cell membrane.
CONDITIONS INSIDE AND OUTSIDE THE CELL: if there is a greater concentration of particles inside the cell, the particles tend to leave the cell (diffusion)
Examples of PASSIVE PROCESSES (do not require energy) include:
SIMPLE DIFFUSION
OSMOSIS
FACILITATED DIFFUSION
Example of ACTIVE PROCESSES (require energy) include:
ACTIVE TRANSPORT
SIMPLE DIFFUSION is….
“The net movement of molecules from a region of relatively high concentration to a region where they are at a lower concentration”
The difference between the two regions is known as the:
CONCENTRATION GRADIENT
When does Diffusion end?
Diffusion ends when all the molecules are evenly distributed (EQUILIBRIUM)
The steeper the CONCENTRATION GRADIENT, the
FASTER THE RATE OF DIFFUSION
FACILITATED DIFFUSION is when:
The process of diffusion REQUIRES THE HELP OF OTHER MOLECULES (such as PROTEINS)
FACILITATED DIFFUSION is often used when ________ molecules (such as GLUCOSE) need to pass through the Cell Membrane.
LARGER
What are the TWO TYPES of PROTEINS involved in FACILITATED DIFFUSION?
Carrier Proteins
Channel Proteins
Explain how CHANNEL PROTEINS assist in diffusion.
Channel Proteins OPEN AND CLOSE to allow certain molecules to pass through the cell membrane
Explain how CARRIER PROTEINS assist in diffusion.
Carrier Proteins embedded in the cell membrane BIND to molecules, CHANGE SHAPE and RELEASE the molecule on the other side of the cell membrane
What is OSMOSIS?
Osmosis is the net movement of water from across a membrane from a high water concentration (low solute concentration) to a low water concentration (high solute concentration).
In OSMOSIS, an area where there is a HIGHER SOLUTE CONCENTRATION is described as being _________
HYPERTONIC
In OSMOSIS, an area where there is a LOWER SOLUTE CONCENTRATION is described as being ________
HYPOTONIC
In OSMOSIS, an area where there is an EQUAL CONCENTRATION OF SOLUTE is described as
ISOTONIC
