LESSON 8 Flashcards
a membrane made of two layers of phospholipids with embedded proteins that separates the insides of the cell from its environment
cell membrane
This is a group of organic compounds that are insoluble in water.
lipids
Examples include fats, waxes, oils, and hormones.
lipids
hydrophilic head
phosphate group
hydrophobic tail
fatty acids
having both hydrophilic and hydrophobic parts.
amphipathic molecule
allows certain substances to pass through but not others.
semi- permeable
hese molecules are madeup of building blocks called amino acids joined by peptide bonds.
proteins
_______ penetrate the hydrophobic core
Integral proteins
Integral proteins that span the membrane are called __________
transmembrane proteins
The hydrophobic regions of an integral protein consist of one or more stretches of ____________, often coiled into ___________
nonpolar amino acids; alpha helices
___________ - spans across the membrane
polytropic or transmembrane
_________ attached to only one side of the membrane
monoprotic
are bound to the surface of the membrane
Peripheral proteins
Functions of Proteins
receptor
channel
transmembrane transport
adhesion
cell-cell recognition
enzymatic function
________ are a special class of proteins that function by binding a specific ligand molecule.
Receptors
When a ligand binds to its ______, the ______ can change conformation, transmitting a signal into the cell.
receptor
common ligands are the
neutral molecules water (H2O), ammonia (NH3), and carbon monoxide (CO) and the anions cyanide (CN-), chloride (Cl-), and hydroxide (OH-).
A __________ is a special arrangement of amino acids which embeds in the cell membrane, providing a hydrophilic passageway for water and small, polar ions.
channel protein
Like all transport proteins, each _________ has a size and shape which excludes all but the most specific molecules.
channel protein
A ___________ is seen, embedded within the membrane. Ions, the small green hexagons, travel through the channel protein.
generic channel protein
A _____________ is a membrane protein involved in the movement of ions, small molecules, and macromolecules, such as another protein, across a biological membrane.
membrane transport protein (or simply transporter)
Only ________ proteins can function on both sides of the bilayer or transport molecules across it
transmembrane
__________ are transmembrane proteins that bind signal molecules in the extracellular space and generate different intracellular signals on the opposite side of the plasma membrane.
Cell-surface receptors
This particular function is useful in the immune system, as it helps the body to recognize foreign cells that may be causing infection, for instance.
cell recognition of proteins
this means that they are able to carry out chemical reactions.
enzymatic activity;
This can be to induce signal transduction of signals into the cell, such as catalyzing phosphorylation of another protein.
enzymatic activity
It is a biomolecule made up of carbon, hydrogen, and oxygen.
carbohydrates
Sugar, starches and fiber are some of its examples.
mostly found on the external surface
carbohydrates
Attached to proteins
glycoproteins
attached to lipids
glycolipids
Forms distinctive cellular markers
carbohydrate
cell-cell recognition
Cell pathogen recognition
carbohydrate
It is a type of lipid, a waxy substance found in cells.
cholesterol
It is essential in the production of other biomolecules like hormones, steroids and vitamin D.
cholesterol
regulates the fluidity of the membrane as temperature varies
cholesterol
*high temperature → _____ fluidity
decrease
low temperature → _____ fluidity
increase
fluid mosaic model by
Singer and Nicolson 1972
FUNCTIONS OF CELL MEMBRANE
Protection
Material Transport
Cell Shape
Compartmentalization
Cell Recognition
Cell Function
It serves as a barrier that separates the components of the cell from its surrounding environment.
Protection
It is a semi-permeable membrane that regulates the transport of materials in and out of the cell.
Material Transport
It serves as the attachment point of the cytoskeleton which aids in maintaining the shape and form of a cell.
Cell Shape
It separates the organelles from each other and from the cytoplasm providing their own environment and functional individuality
Compartmentalization
It enable cells to identify other cells and foreign substances.
Cell Recognition
It plays a vital role in the performance of the cell’s function i.e. locomotion, absorption,impulse transmission
Cell Function
