Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
68 Cards in this Set
- Front
- Back
2 general classes of cells?
|
1. sex cells
2. all other cells in the body |
|
relationship between _______ & _______ determines how large a cell will be.
|
cell volume & cell surface area
|
|
cell dividend into 3 parts:
|
1. plasma membrane
2. cytoplasm 3. nucleus |
|
plasma membrane
|
1. seperates the intracelluar from the extracelluar
2. selective barrier; 3. monitors flow in and out of cell; the communication 4. structural support of cell |
|
cytoplasm divided into ______
& ________ |
cytosol (intracellular fluid) &
organelles |
|
diff between cytosol and extracellular fluid
|
1. more K+ in cell; more Na+ outside the cell
|
|
2 types of organelles ______&________
|
1.non-membraneous ie...(cytoskeleton,microvilli,
ribosomes) 2. membraneous ie... (ER,golgi complex, mitochondria) |
|
nucleus
|
genes inside that control cell structure and activities
|
|
another name for the plasma membrane
|
fluid mosaic model
|
|
lipid bilayer the backbone of the plasma membrane is made up of 3 types of lipid molecules
|
1. phospholipids: contain phosphate groups
2. cholesterol: stabilize membrane 3. glycolipids: appear only in membrane layer facing extracellular fluid |
|
another name for polar portion of phosphate head
|
hydrophillic
|
|
another name for the non-polar
two long fatty acid tails |
hydrophobic
|
|
integral proteins:
|
membrane protein that extends into or through the bilayer; part of the membrane if removed causes damage;
*human blood types and transfusion compatibility are determined by glycomproteins* |
|
transmembrane proteins
|
integral proteins that stretch across whole bilayer (involved in transport)
|
|
membrane protein channels:
|
formed by transmembrane proteins; selectively take in h20 and small solutes
|
|
membrane carrier proteins
|
bind polar substance at one side change the shape move to other side of membrane
|
|
receptor proteins
|
integral proteins that serve as cell recognition, binding specific molecules
|
|
ligand
|
specific molecule that binds to a receptor
|
|
cell id markers (recognition proteins)
|
enable cell to recognize other cells of the same kind during tissue formation & respond to dangerous foreign cells
|
|
carbohydrate portions of glycolipids,glycoproteins, and proteoglycans form sugary coat called _______
|
glycocalyx
|
|
glycocalyx does
|
1. allow cells to recognize eachother (identical in twins only)
2. but different from cell type to cell type ie...sperm recognizes ovum by its unique glycocalyx 3. protects cell from being digested by enzymes in extracelluar fluid 4. attract a film of fluid to surface of cell that lubricates and protects cell membrane |
|
define membrane fluiditiy 2 reasons:
|
1. # of double bonds
2. amount of cholesterol (strengthens bilayer but too much accumiliation causes celluar rigiditity) |
|
2 types
membrane permeability |
1. freely permeable
2. selectively permeable |
|
selective permeable membrane has many factors
|
1. size,shape etc of substance trying to pass
2. *only living membranes can be selectively permeable* |
|
2 types of ions or molecules higher concentrations found in: 1. extracellular fluid
2. cytosol |
1. 02 & Na+
2. K+ and C02 difference lies in the chemical concentration on eachside of the plasma membrane |
|
electric gradient ( resting potential/ transmembrane potential) difference in + & - charged ions on each side of the plasma membrane
|
1. transmembrane potential in a resting cell is called the resting potential
2. inner surface usually more negatively charged 3. each cell has its own potential (-10 to -100 mv) skeletal muscle -85mv neurons -70mv cardiac muscle cell -90mv adipocytes -40mv |
|
ions held on either side of cell membrane have potential energy which is stored in the transmembrane potential
|
use of potential energy cause
1. action potential 2. muscle contraction 3. glandular secretions |
|
definition of electrochemical gradient
|
ions are influenced by both the chemical and electrical gradient combined is the definition
|
|
substances cross plasma membrane via transport process by 2 criteria
|
1. they are mediated or nonmediated
2. they are active or passive |
|
mediated transport
|
materials move through with assistance of a transporter protein.
|
|
passive transport
|
substance moves down concentration/electric gradient
using its own kinetic energy; can be mediated or nonmediated |
|
active transport
|
cell energy (ATP) used to drive cell "uphill" against gradient;
all are mediated transports |
|
example of non-mediated passive transport process
|
diffusion
1a. through the lipid bilayer 2a. through a channel |
|
mediated passive transport process
|
facilitated diffusion
|
|
active transport process
|
uniporters/coupled transporters
2a. symporters (move in same direction) 2b. antiporters (move in opposite direction across membrane) |
|
2 types of vesicular transport
|
endocytosis & exocytosis
|
|
principles of diffusion
|
1. both solutes and solvents undergo diffusion
2. a molecule (in solution) will diffuse from high concentration to low concentration (net diffusion) |
|
factors that influence the diffusion rate
|
1. greater the diff in the concentration between the 2 sides of membrane; faster the diffusion;
|
|
osmosis
|
net movement of solvent through selectively permeable membrane
(h20 moves from high concentration to lower ones) or (h20 moves from one side of the plasma membrane to the other) |
|
hydrostatic pressure
|
pressure exerted by fluid on the walls that contain it
|
|
osmotic pressure
|
pressure required to prevent h20 from moving when seperated by a selectively permiable membrane
*higher concentration of solutes; higher the osmotic pressure of solution* |
|
h20 cross the p.m. in 2 ways
|
1. diffusion through lipid bilayer
2. through aquaporines (transmembrane proteins that act as water channels) |
|
2 requirements for osmosis
|
1. difference in the concentration on 2 sides of a s.p.m.
2. membrane must be relatively impermeable to solute; (solutes that can't pass through are said to be osmotically active) |
|
rules of osmolality
|
1. osmotic pressure depends on ratio of solute to solvent not on the chemical nature of solute molecules
2. |
|
300 mm glucose solution;
.3Osm glucose solution; 300 mOsm glucose sol; & 0.9% NaCl solution which ionizes to a total concentration of 300mOsm |
have same osmolality and osmostic pressure as plasma
|
|
because 300 mOsm of glucose & 0.9% NaCl have same osmolality
|
said to be iso-osmotic to plasma
*plasma and i.c.f have same osmolarity* |
|
define tonicity
|
effect of a solution on osmotic movement of water.
|
|
A solution may be isosmotic but not isotonic
|
ie...300mOsm urea
when a solute in the isosmotic solution can freely pass |
|
solutions have lower #'s of solutes than that of plasma so you have
|
hypo osmotic to plasma
hypo tonic to plasma |
|
solutions have higher #'s of solutes than that of plasma
|
higher osmotic pressure; therefore are hyper osmotic to plasm; also if osmotically active they become hypertonic to plasma
|
|
filtration is a _______
|
passive process involving a pressure gradient
|
|
filtration is used to
|
force fluid out of capillaries and the kidneys
|
|
diffusion through membrane channels is slower
|
than going through the lipid bilayer ( smaller portion of membrane surface area is occupied by channels)
|
|
ion channels may be
|
open always (leakage)
"gated" 1. chemically (ligated) 2. voltage 3. mechanically |
|
facillitated diffusion
|
solutes that are to highly charged, polar, large in size to pass through bilayer through membrane channels can cross by this method
|
|
rate of facilitated diffusion
|
determined by the steepnes of the concentration gradient of both sides of membrane...
& number of transporters available (transport maximum) |
|
process of facillitated diffusion
|
exhibits saturation
|
|
active transport
|
solutes that need to move uphill against its concentration gradient (Na+,K+,H+, amino acids,) cross by this process
|
|
active transport is mediated or an energy requiring process;
exhibits a transport max and saturation....what is the source that drives active transport? |
ATP..is the source of primary active transport
energy stored in the ionic concentration gradient is the source of secondary active transport |
|
transport proteins that carry out primary active transport called
|
pumps....
|
|
the Na+/K+ pump
|
keeps the intracellular level of Na+ low and K+ high (maintains membrane potential)
|
|
vesicular transport
|
small sac that buds of from existing membrane...
transport from one structure to another within the cell... take in substance from the extracellular fluid... release substance into the e.c.f |
|
main types of vesicular transport
|
endocytosis&exocytosis
|
|
endocytosis
|
moves material from the e.c.f. into the cell in a vessicle formed by the plasma membrane...
|
|
3 types of endocytosis
|
1. receptor mediated endocytosis....highly selective type endocytosis (forms after a receptor protein in the plasma membrane binds to a specific ligand in the e.c.f
2. bulk phase endocytosis (pinocytosis) 3. phagocytosis..a form of endocytosis in which a large solid particle (bacteria,virus) are taken into the cell vital for body defense mechanism |
|
exocytosis is
|
material moved out of the cell by the fusion of vesicles with the plasma membrane...
especially important in nerve cells (release neurotransmitters) and secretory cells (secrete digestive enzymes or hormones) |
|
cytoplasm divided into
|
cytosol and organelles
|
|
cystol consists of about
|
75-90% h20
site of many chemical reactions and cell activites like energy production...building blocks for cell structure |