Chapter 3
Exocytosic
method by which cells export products for use in another location
Cholesterol
helps the membrane retain its flexability
Consumed by the cell by endocytosis, inside the cell, the cholesterol is broken down and used to make a variety of other useful molecules, such as the
hormones estrogen and testosterone
diffusion
in which a particle, called a solute is dissolved in a gas or liquid ( a solvent) and moves from an area of high solute concentration to an area of lower concentration
Primary active transport
occurs when energy from ATP is used to fuel the transport of molecules
What are the types of endocytosis
phagocytosis, pinocytosis, and receptor mediated enocytosis
2 types of active transport
primary and secondary
Recognition proteins
provide a "fingerprint" for the cell, so it can be recognized by other cells.
Transport proteins
provide a passage way for molecules to travel into and out of the cell
isotonic solution
solute concentration are balanced (water movement is balanced)
hypertonic
solute concentration are higher in the extracellular fluid (water diffuses out of cell)
The direction of osmosis is determined by the total amount of
solutes on either side of the membrane
Receptor protiens
surface or trans membrane protein, bind to external chemicals in order to regulate process within the cell.
The largest human cell is
the egg cell
is water polar or non polar
Polar molecule b/c other polar molecules mix easily with water
Pinocytosis
"drink and container" the process of cells taking in dissolved particles and liquids
Prokaryotic cells
1st cells on earth, no nucleus- DNA in the cytoplasm , single celled organisms, no organelles, contain cytoplasm. contain ribosomes, can conduct phtosythesis
Cell Theory
All living organisms are made up of one or more cells. The cell is the smallest thing that is alive. cells arise from other, preexisting cells.
what are the types of molecules used in the plasma membrane?
Carbohydrate chains, cholesterol
Robert Hooke Named Cells
Cellulae, from the Latin name meaning small rooms
Most molecules, however, cant get through plasma membrnaes on their own. They may be _____ and, hence, are repelled by the ____ middle region of the ______.
Electrically charged, hydrophobic, phospholipid bilayer
Molecules that can mix with water are described as
Hydrophilic "water loving"
hypotonic
Lower, solute concentration are lower in the extracellular fluid (water diffuses into cell)
Eukaryotic cells
Nucleus, DNA, multicellular and unicellular, we are eukaryotes, Plant, Animal, Fungi and Protist cells are all eukaryotic, bigger than prokaryotes
What are the molecules that are small and carry no charge and can pass directly through phospholipid bilayer of the membrane with out the assistance of any other molecules
Oxygen and carbon-dioxide
____ is the spontaneous diffusion of molecule across membrane.
Passive transport
The two process are largely the same, except that the vesicles formed during _____ are generally much smaller than those formed during______.
Pinocytosis Phagocytosis
Every cell is bordered by
Plasma Membrane (gate keepers) regulates what enters and exits the cell.
Carbohydrate chains
Provide "fingerprints" for the cell, so it can be recognized by other cells
what are the types of membrane proteins?
Receptor proteins, recognition, transport, enzymatic
Passive transport
The molecular movement occurs spontaneously, with out the input of energy
Who uses phagocytosis to consume entire organisms either as food or as their way of defending against pathogens
amoebas and other unicellular protists, as well as white blood cells, use phagocytosis to consume entire organisms either as food or as a way of defending against pathogens (disease causing organism or substance)
For every 50-100 phospholipids in the membrane, there is one protein molecule called
Transmembrane proteins which penetrate right through the lipid bilayer from one side to the other -surface proteins or peripheral proteins, reside primarily on the inner or outer surface of the membrane
Osmosis
Type of passive transport by which water diffuses across a membrane, in order to equalize the concentration of water inside and outside the cell.
endocytosis
a cellular process in which large particles, solid or dissolved, outside the cell are surrounded by a fold of the plasma membrane, which pinches off, forming a vesicle, and the enclosed particle now moves into the cell.
each molecule of LDL is
a cholesterol globlue coated by phospholipids
Phospholipids
a layer of lipid molecules all packed together
All these types of endocytosis form
a vesicle, and then pinching off the vesicle so that it is inside the cell but seprated
Enzymatic proteins
accelerate intracellular and extracellular reactions on plasma membrane
Secondary Active Transport
active transport in which there is no direct involvement of ATP (adenosine triphosphate) , the transport protein simultaneously moves one molecule against its concentration gradient while letting another flow down its concentration gradient
Receptor mediated endocytosis
by which cells engulf specific particles
What kind of proteins are attached to the phospholipid bilayer?
carbohydrates and lipid molecules
The 2 tails of the Phospholipids are long chains of ____ and ___ atoms. B/c the electrons in these bonds are shared equally, the carbon- hydrogen chains are ___.
carbon and hydrogen nonpolar
exocytosis
cells the manufacture molecules( such as digestive enzymes) for use elsewhere in the body must get those molecules out of the cell
active transport
cells use energy to move small molecules into and out of the cell
one of the most important receptor mediated endocytosis is
cholesterol which circulates in the bloodstream is in the form of particles called low density lipoprotiens
What are the types of passive transport?
diffusion and osmosis
Hydrophobic
do not mix with water
Polar
electrons are not shared equally among atoms
What is a cell?
the most basic unit of any organism, smallest unit of life that can function independently and perform all the necessary functions of life, including reproducing itself.
Low Density Lipoproteins coat are recognized by receptor built into
the plasma membrane of liver cells
Phagocytosis
the process by which relatively large particles are engulfed by cells by which cells engulf large particles
With the heLp of a channel or carrier molecule
these molecules may still be able to diffuse across the membrane, down their concentration gradient
Facilitated diffusion
when a spontaneous diffusion across a plasma membrane requires a transport protein