chapter 5 Flashcards
fluid mosaic model
Diverse protein models suspended in a fluid phospholipid bilayer
The presence of cholesterol keep phospholipids from packing too tightly
Attachment Protein
proteins that attach to the ECM (fibers of extracellular matrix) and cytoskeleton help support the membrane and can coordinate external and internal changes
Receptor Protein
bind signaling molecules and relay the message by activating other molecules in the cell (signal transduction)
Active Transport Protein
allow specific ions or molecules to enter or exit the cell
Junction Protein
form intercellular junctions that attach adjacent cells
Glycoprotein
serve as ID tags that are recognized by membrane proteins of other cells
Enzymes
to assist reactions in the cell?
evolution of membranes
Phospholipids among the first organic molecules formed
Can spontaneously self assemble into simple membranes
purposes of cell membrane
encloses assembly of molecules
regulates chemical exchanges w/ environment
what kind of energy do molecules have
thermal energy, because of their constant motion
diffusion
particles moving from an area of high to low concentration
passive transport
diffusion across a biological membrane down a concentration gradient (high to low)
Osmosis
diffusion of water
isotonic solution
solute concentration equal between solution and cell
Hypotonic solution
solute concentration is lower than in the cell
is the water filled cell
Hypertonic solution
solute concentration is higher than in the cell
is the small, shriveled cell
osmoregulation
preventing excessive uptake or excessive loss of water
plasmolysis
cell loses water
facilitated diffusion
use of channel proteins to move substances across a membrane
(when molecules still have a net movement of a high concentration to a low concentration but they may be too large or have other characteristics that prevent them from directly traveling across the selective cell membrane, therefore they have to go through a protein channel
active transport
molecules go against concentration gradient, powered by ATP
ATPs role in active transport
ATP energizes transport protein
endocytosis
the cell fuses with the molecules it’s taking in, in order to bring it inside, form vesicles that can be taken inside the cell
exocytosis
used to get rid of cell waste and getting valuable materials out, vesicle fuses with membrane
Phagocytosis
pods stretch out around what they are going to engulf, and then it pulls it in, “cell eating”
Pinocytosis
allows cells to take in fluids, “cell drinking”
Receptor-mediated endocytosis
incoming substances have to bind to receptors to get in
energy
the capacity to cause change
kinetic energy
energy of motion, ex: heat and light
potential energy
Stored energy dependent upon an object’s location/structure, ex: chemical
Life depends upon the fact that E can convert into different forms
first law of Thermodynamics
E can be transferred/transformed but cannot be created or destroyed
endergonic (endothermic)
Requires net input of E
Products’ covalent bonds store more E than reactants
Ex: photosynthesis
exergonic (exothermic)
Releases E
Reactants’ covalent bonds contain more E products
Ex: cellular respiration
metabolism
Is the total amount of chemical reactions in an organism
Metabolic pathways
Identify the role of ATP in cellular work
Cellular work is sustained because ATP is a renewable resource continually generated by cells - think “recycling”
ATP
powers cellular work
Consists of one adenine, one ribose, and three phosphate groups
E in an ATP molecule lies in the bonds between its phosphate groups
ATP powers cellular work through couples reactions
phosphorylation
the chemical addition of a phosphoryl group
tonicity
the tendency of a cell in a given solution to lose or gain water
Transport protein
has a pore with a hydrophilic channel for the passage of charged particles
Carrier protein
large substance binds to protein, protein changes shape, release the large substance
