Bio Exam 2 study guide 3

michelleburkee2's version from 2015-10-05 05:18

Section 1

Question Answer
cell membranes have _____ heads and ____ tailshydrophillic; hyrdophobic
basic structure of membraneproteins suspended in a double layer of phospholipids
what are phospholipids responsible for in the membrane?for the isolating function of membranes
what are proteins responsible for in the membrane?selectively exchanging substances and communicating with the environment. Also control biochemical reactions and form attachments
one of their functions is to selectively exchange substances*proteins*
one of their functions is to communicate with the environment and form attachmentsproteins
five functions of the plasma membrane1. isolates the cell's contents from the external envieonment 2. regulates the exchange of essential substances 3. allows communication between cells 4. creates attachments within and between cells 5. it regulates biochemical reactions
fluid mosaics in which proteins move within layers of lipidscell membrane
what do membranes consist of?"patchworks" of different proteins that constantly shift and flow within a fluid formed by a double layer of phospholipids
the fluid phospholipid bilayer helps to __________isolate the cell's contents
the basis of membrane structure consist of a polar, hydrophilic head and two nonpolar hydropobic tailsphospholipids

Section 2

Question Answer
the basis of cell membrane structurephospholipids
phospholipids have a _______ head and ______ tailspolar, hydrophillic (h) and TWO nonpolar hydrophobic (t)
the fluid part of the membranephospholipid bilayer
The heads or tails are on the outside of the phospholipid bilayerheads
plasma membranes face ___________ exterior and interior watery environments
what drives the phospholipids into bilayers?hydrophobic and hydrophillic interactions
hydrogen bonds and the formation of the membranehydrogen bonds between water and hydrophillic heads cause the heads of the outer layer to orient outward toward the watery exterior while the heads of the inner layer face the interior
hydrophobic forces and the formation of the membranethe nonpolar tails, being hydrophobic, face the inside of the membrane, away from the watery environment of the bilayer
the phospholipid bilayer has a _______ environmentwatery
what properties do membranes have to isolate cell contents from the external environment?permability and fluidity
what is kept out and what is kept inpermability
what type of substances that cannot cross bilayers?water soluable substances
what are examples of substances that cannot cross bilayers and why cant they cross the bilayer?salts, ions, amino acids, and sugars. They cannot cross the bilayer because they are water soluable
what type of substances can cross the bilayers?very small molecules and lipid soluable molecules
what are examples of substances that can cross the bilayers and why can they?water, oxygen, carbon dioxide, and steroids. They can cross the bilayer because they are either very small or lipid-solauble
individual phospholipid molecules are not bonded to one another so they move in relation to each other and allow the membrane to remain flexible
some of the phospohlipids have unsaturated fatty acids, whose double bonds introduce ______kinkds into their tails
cell surface markerglycoprotein

Section 3

Question Answer
Can salts cross the lipid bilayer?no
Can ions cross the lipid bilayer?*no*
can amino acids cross the lipid bilayer?%no%
can sugars cross the lipid bilayer?$no$
can water cross the lipid bilayer?yes
can oxygen cross the lipid bilayer?*yes*
can carbon dioxide cross the lipid bilayer?%yes%
can steroids cross the lipid bilayer?$no$
very small molecules and lipid soluable molecules ______ cross the lipid bilayercan
water soluable substanse ________ cross the lipid bilayercannot
_____ and ______ effect the rate of diffusion across the membranesize and charge
individual phospholipid molecules _______ bonded to one anotherare not
why is the membrane flexible?because individual phospholipid molecules are not bonded to eachother but move in relation to one another
more unsaturated fatty acids in phospholipids=greater fluidity
more saturated fatty acids in phospholipids=less fluidity
cells must remain _____flexible
some of the phospholipids have unsaturated fatty acids, whose ____ bonds introduce kinks into their tailsdouble bonds
membranes are more fluid at _____ tempshigh
membranes are less fluid at ______ tempslow
cell membranes of organisms living in low temperatures tend to be more ____unsaturated
unsaturated= ____ kinksmore
saturated= ______ kinksless
more kinks=help maintain fluidtiy
_______ stabilizes membranescholesterol
membranes _______ when they get coldsolidify
membranes have bad functioning when theyget cold and solidify
more unsaturated phospholipid tails=can remain liquid at low temps
proteins are ______ the phospholipid bilayerattached to
many proteins have ______attached carbohydrates on their outer membrane surface
glycoproteinscarbohydrates attached to proteins on their outer surface
help in cell communication and transportglycoproteins
5 types of membrane proteins:Enzymes, Recognition proteins, Receptor proteins, Connection proteins, and Transport proteins
proteins that promote chemical reactions that synthesize or break apart biological moleculesenzymes
extracellular matrixa web of protein and glycoprotein fibers that fills spaces between animal cells
some _______ are used to synthesize the extracellular matrixplasma membrane enzymes
glycoproteoins that serve as identification tags on the surface of a cellrecognition proteins
trigger cellular responses upon binding of specific moleculesreceptor proteins
how does the receptor protein process work?messanger molecule binds with receptor protein, messanger molecule binding activates the receptor protein therefore changing it's shape, and then the activated receptor protein stimulates a response in the cell
signal transducersreceptor proteins