Fill In Chapter 8

 

Campbell Reece Biology Fill In Chapter 8

Membrane Structure and Function

It would take over ________ plasma membranes to equal the thickness of a piece of paper.

Plasma membranes exhibit selective p___________, meaning they keep some stuff out and keep some stuff in.  This makes life possible because life can then control its internal environment. 

The most important ingredients of membranes are l______ and pr_________, but c_____________ are also important.  A phospholipid has a hydro________ region and a hydro____________ region. 

Plasma membranes are ___ molecules thick.

pp. 140 – 141

According to the fl____ mo_____ model of membranes, the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids.

Models are proposed as hypotheses, ways of organizing and explaining existing i________. 

Membranes are fl____, they dr___, but don’t usually flip.

Some proteins dr_____, also, even though they are larger.  They may be moved or held in place by the cyt_______.

As the cell cools, the movement slows and s_____, like solidifying bacon grease. 

142 – 143

separate project, draw page 142 animal cell’s plasma membrane

Membranes must be f____ to work properly – about as much as salad oil.  When it cools and becomes solid it changes its per___________ and the enz_______ may become inactive.  Cells may change their chemical makeup during different parts of the year to keep from going solid.

More than ____ kinds of proteins have been found in the membrane of red blood cells.

There are two kinds of proteins in the membranes.

I_____ proteins go at least as far as the hydrophobic tails inside the membrane, and some go all the way through. 

P______ proteins are not embedded , they are loosely bound to the surface.

Inside the cell, on the cytoplasmic side, the cyt______ can hold some proteins bound to the membrane. 

Carbohydrates are always on the __________ side of the cell membrane.

The carbohydrates on the outside help cells re______ze each other.  If this carbohydrate signaling isn’t there, the cell is considered a foreign cell to be re________. 

144-145

 The carbohydrate markers on the outside of the red blood cells is also the difference between human blood types A, __, ___, and ____.

The fluid mosaic allows cells to tran_____ across cellular boundaries.

There is constant flow in and out of cells.  Muscle cells take in s______, a_______ acids, and n________ and kick out w_______.  It brings in O_________ and moves out c_________ d_________, and regulates i_______ like sodium, potassium, calcium and chloride ions. 

Substances that can’t pass through the phospholipid part of the membrane can sometimes go through the tr_______ proteins.  Some are like a tunnel, others like a ferry.  These protreins only transport specific substances. 

Transport can be p______ or ac_______.

List the functions of membrane proteins from figure 8.9

Solutes that can pass through the membrane will diffuse from an area of greater concentration to an area of lower concentration until the movement from one side to the other equals that from the other side to the one and the situation has reached e_________.

This kind of movement is p_____, requiring no energy use by the cell.

pp. 146 – 147

Passive transport of water is called o__________.  Water will move until the concentration in a solute is evened out.

A solution with a higher concentration of a solute is h___________.

A solution with a lower concentration of a solute is h_____.  Solutions of equal concentration are said to be i_________.

Cell survival depends on being able to balance water uptake and loss.

In an isotonic environment, the volume of an animal cell is s_____ -- water flows in and out at the same rate.  If the environment becomes hypertonic, the cell will l_____ water to its environment;  it will shr_____ and probably die.  If you put an animal in salt water it may kill it.  If you put a cell in a hypotonic solution, it will take in water and sw___ and burst (l____).  A cell without a rigid wall has to live in an isotonic environment or have adaptations for osmo______, controlling water balance.

Paramecium lives in pond water, which is hypotonic, so its membrane is less per__________ and it has a con_______ v________ that pumps water out.

The cells of plants and prokaryotes and fungi, and some protists, have w______. 

When a cell with a wall is in a hypotonci solution, instead of bursting it becomes t_____ (very firm).  If it is in an isotonic solution it becomes f_____ (limp)  if it is in  a hyper tonic environment, it will lose water and shrivel, and the membrane will pull aay from the wall, causing pl_______ and usually killing the cell.

Faci_________ diffusion is when the proteins help substances move across the membrane.

148—149

Transport proteins are specific for one kind of “passenger”, and once they are all filled up the system is s_________ and can’t transport any more until the proteins open up.  That limits the rate of transport.  You can inhibit the transport across the membrane by these proteins by using molecules that re______ the real passengers, the imposter blocks the transport.  They don’t catalyze a chemcial reaction, though, but a physical process – moving through the membrane.

Some transport proteins provide co_______;  they are called ch______ proeints.  Water channel proteins are called a__________.  Some are g_______ channels, and something must open the gate or close it.  This might be electrical or ch_________.

Some transport proteins change sh_____. 

In cys______, the protein that transports cystine is absent in kidney cells, so a person can develop kidney st_______. 

Ac______ transport is necessary to move substance to a higher concentration, instead of equilibrium – it’s like moving something uphill.

Active transport means the inside of a cell can have a higher concentration of something than the outside, like animal cells have high concentrations of po_____ and s________. 

Cells use the energy of A_____ for active tranport.  The proteins can “pump” this way. 

All cells have v______ across their plasma membranes.  Voltage is the e_____ potential energy, a separation of opposite charges.  The cytoplasm is n___________ in charge because of the way a______ and c________ are distributed inside and outside of the cell.

This membrane potential acts like a b_________.  The cell is negative inside so c_____ (positive ions) want in, and an_______ (negative ions) want out. 

150 – 151

Draw figure 8.16

The main electrogenic pump of plants, bacteria, and fungi is a pr_____ pump, which actively transports hydrogen i_____ (protons) out of the cell. 

Co______ is when a substance pumped across a membrane does w____ as it leaks back and another transport protein uses that work.

Ex______ is when the cell secretes macromolecules by the fusion of vesicles with the plasma membrane.  Secretory cells use this, like the pancreas making insulin and secreting it into the blood using exocytosis.  Neurons use exocytosis to release chemcial signals.

In en__________, the cell takes in macromolecules and particulate matter by forming new vesicles from the membrane, the membrane sinks in to make a pocket, pinches in, and carries the substance in.

The three types of endocytosis are ph__________ (“cellular eating”), p_________ (“cellular drinking”), and r__________________.

Cholesterol enters the cell using re__________________________ endocytosis.  If cholesterol can’t enter the cells because the binding receptors are defective, it accumulates in the blood and causes atherosclerosis, narrowing of the blood vessels.

152

Endocytosis and Exocytosis add and subtract plasma membrane, it about evens out.