Biology Cell Membrane Flashcards
the SEMI-PERMEABLE MEMBRANE surrounding the cytoplasm of a cell.
Cell Membrane
The functions of the cell membrane are as follows:
(1) Maintain the shape of the cell;
(2) acts as a
barrier (separates the outside and inside environment of the cell); and
(3) The cell membrane
REGULATES THE TRANSPORT OF THE MATERIALS entering and exiting the cell.
THE STRUCTURAL COMPONENTS OF THE CELL MEMBRANE
describes the structure of the plasma membrane as a mosaic of components —including
phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character
the Fluid Mosaic Model
Fluid Mosaic Model were by
Seymour J. Singer and Garth L. Nicolson (1972).
Main fabric of the cell membrane.
PHOSPHOLIPIDS
The cell membrane is composed of two layers of
phospholipids wherein
the heads are composed of polar molecules (hydrophilic), whereas the tails are
nonpolar (hydrophobic).
Transport substance through cell membrane.
extend from both
side of the phospholipid bilayer. Carrier and channel proteins are examples of this.
INTEGRAL PROTEIN
Involved in cell signaling. They are smaller than the integral protein and
usually found either at the top or lowest layer of the phospholipids.
PERIPHERAL PROTEIN
involved in cell-to-cell recognition.
CARBOHYDRATES
holds the phospholipids together so that they don’t separate too far or compact too
tightly.
CHOLESTEROL
THE TRANSPORT MECHANISM OF THE CELL MEMBRANE
PASSIVE AND ACTIVE
TRANSPORT
movement of substances across membranes without energy expenditure.
The movement of substance is from high to low concentration.
PASSIVE TRANSPORT
There are three types of PASSIVE TRANSPORT
- SIMPLE DIFFUSION,
- FACILITATED DIFFUSION, AND
- OSMOSIS
the movement of molecules through a cell membrane without using the channel protein
from an area of high concentration to low concentration
this is suited for small nonpolar molecules (O2, CO2, N2, etc.)
SIMPLE DIFFUSION
the movement of molecules through a cell membrane with the help of channel protein
from an area of high concentration to low concentration.
this is suited for big polar molecules (ex. Glucose and amino acids)
FACILITATED DIFFUSION
The movement of solvent across a membrane from high to low solvent concentration.
Channel protein is also used in this process.
movement of solvent (water and alcohol)
solvent follows the concentration of solute
Water molecules follow the concentration of solute. They may also require a channel protein
since they cannot pass the phospholipid bilayer because of their polarity.
OSMOSIS
(too much solvent outside)
hypertonic
(too much solute inside)
hypotonic
equal
isotonic
movement of across a membrane which requires the expenditure of energy, usually in the
form of adenosine triphosphate (ATP)
The movement of substance is from low to high concentration.
ACTIVE TRANSPORT
➢is a type of active transport that moves large molecules, parts of cells, and even whole cells, into a cell.
BULK TRANSPORT
➢There are two types of bulk transport:
- ENDOCYTOSIS
- EXOCYTOSIS
A process by which cells absorb external material by engulfing it with the cell membrane.
ENDOCYTOSIS
