ch. 3-1 plasma membrane separates the cell from its surrounding environment and performs various functions

integral proteins

also known as transmembrane proteins, span the width of the membrane.

what cannot cross the plasma membrane

water and solutes

proteins which are much denser than lipids account for about

55 percent of the weight of a plasma membrane.

plasma membrane is how thick

6 to 10 nm

what else is the plasma membrane called

a phospholipid bilayer

recognition proteins (identifiers) do what

allow the cells of the immune system to recognize other cells as normal or abnormal

peripheral proteins

are bound to the inner or outer surface of the membrane and are easily separated from it.

anchoring proteins do what

attach the plasma membrane to the inside of the cytosketon a nework of supporting filaments int he cytoplasm. or outside the cell, other mmembrane proteins may attach the cell to extracellular protein fibers.

the composition of the entire plasma membrane can change over time

because large areas of the membrane surface are continually being removed or recycled.

cell biology inegrates aspects of

biology chemistry and physics

what do carrier proteins do

carrier proteins bind solutes and transport them across the plasma membrane and require ATP as an energy source.

what do enzymes do

catalyze reactions in the extracellular fluid or the cytosol depending on the location of the protein and its active site. for ex. dipepties are broken down into amino acids by enzymes on the exposed membranes of cells that line the intestinal tract.

what is the cell theory

cells are the building blocks of all plants and animals all cells come from the division of preexisting cells cells are the smallest units that perform all vital physiological functions each cell maintains homeostasis at the cellular level. homesostasis at the level of the tissue organ organ system and organism refelcts the combined and coordinated actions of many cells.

which type of integral protein allows water and small ions to pass through the plasma membrane

channel proteins

some integral protiens contain a central pore or

channel that forms a passageway completely across the plasma membrane.

channels are very important

for ner ve impuluse transmission and muslce contraction.

sex cells are also called

germ cells or reproductive cells

a phospholipid contains what kinds of ends

hydrophilic end (the phosphate portion) and a hydrophobic end (the lipid portion)

enzymes in the plasma membrane may be

integral or peripheral proteins.

what can channels cross through them?

ions and water soluble materials.

what does the cell membrane consist of

lipids proteins and carbohydrates

functions of glycocalyx

lubrication and protection (form a viscous layer that protects the plasma membrane), anchoring and locomotion (the components are sticky), specificity in binding (can function as receptors), and recognition. (cells involved wih the immune response recognize glycoproteins as normal as abormal)

identify the components of the plasma membrane that allow it to perform its characteristic functions

membrane lipids, membrane prooteins and membrane carbohydrates

what are the fnction of the plasma membrane (cell membrane)

physical isolation regulation of exchange with the environemnt sensitivity to the environment structural support

list the general functions of the plasma membrane

physical isolation for homeostasis regulation of exchange for the environemtn

carbohydrates in the plasma membrane are components of complex molecules such as

proteoglycans, glycoproteins and glycolipids.

all cells that are not sex cells are

somatic cells.

what gives tissues stability

specialzed connections between plasma membranes, or between membranes and extracellular materials

ligands are

specific extracellular molcules from a small ion like calcium to a relatively large and complex hormone. for ex. insulin as a ligand binding to a receptor protein to increase the rate of glucose absorption of the cell.

hydrophilic heads are in contact with

the aqueous environment on borth sides of the membrane, the interstitial fluid on the outside and the cytosol on the inside

hydrophobic tails form

the interior of the membrane

which of the following components of the plasma membrane is responsible for the membrane to form a physical barrier between the cell's internal and external environments?

the phospholipid ilayer (hydrophilic and hydrophobic tails)

receptor proteins in the plasma membrane are sensitive to what

the presence of ligands

what is cytology

the study of cellular structure and function.