MODULE 2 Flashcards

Question

intergral proteins

Answer 1

(transmembrane and lipid anchored) -wide variety of functions

Answer 2

attaches to intergal proteins, participate in cell signalling and attachment of cytoskeleton

Answer 3

wide variety of functions

Answer 4

water 42 of 70 kg is water 60% of the body is water

Answer 5

osmotic equilibrium fluid concentration are equal; the amount of solute per volume solution

Answer 6

osmosis (water tends to follow solutes) water can move freely between intracellular and extracellular space aquaporin channels (13 different types) -involved in short term and long term regulation of body balance

Answer 7

does not equal ECF = high amount of sodium and chloride, low potassium IF= low cholride and sodium, high potassium many of the solutes are ions with an electrical charge, electrical disequilibrium

Answer 8

water moves via osmosis until osmotic equilibrium is reached -osmotic pressure is the pressure that would have to applied to oppose and prevent osmosis

Answer 9

describes the number of particles in solution -interested in osmotically active individuals particles as opposed to entire molecules

Answer 10

by knowing the concentrations of each solution

Answer 11

280-296 mOsm

Answer 12

solutions have identical osmolarities

Answer 13

greater than describes the solution with the higher osmolarity

Answer 14

describes the solution with the lower osmolarity

Answer 15

describes cell volume changes tonicity is a term used to describe a solution and how that solution would affect cell volume if a cell were placed in the solution and allowed to come to equilibrium hypotonic=lysed isotonic = normal hypertonic= shriveled

Answer 16

-Osmolarity describes the number of solute particles dissolved in solution (mOsm/L) and can be measured -Tonicity has no units, it is a comparable term -Osmolarity can be used to compare two solutions, tonicity always compares a solution and a cell and describes the solution -Osmolarity does not tell you what happens to a cell placed in solution, tonicity tells you what happens to cell volume when placed in a solution -depends on the nature of solutes (wether or not they can cross cell membranes) -tonicity depends on the concentration non-penetrating solutes

Answer 17

is the overall solute concentration of a compartment, takes into account all solutes in the compartment, penetrating and non-penetrating

Answer 18

describes a solution to a cell, solely on how the cell volume responds when placed in a solution. Tonicity is only concerned with non-penetrating solutes. Non-pentrating solutes determine wether a cell volume changes occurs (wether water moves into ro out of the cell). Penetrating solutes can cross the cell membrane and will do so until reaching equilibrium across the membrane when the cell is exposed to the solution, which is why they do not contribute to cell volume changes

Answer 19

wear can move freely between the ECF and the ICF but this is not the case for majority of substance cell membranes are selectively permeable -what crosses depends on the properties of the cell membrane (lipid and protein composition) and the substance (size and lipid solubility)

Answer 20

the movement of molecules form an area of higher concentration to an area of lower concentration

Answer 21

1. diffusion uses the kinetic energy of molecular movement and does not require an outside energy source 2. molecules diffuse from an area of higher concentration to an area of lower concentration 3. Diffusion continues until concentration comes to equilibrium. molecular movement continues however, after equilibrium has been reached 4. Diffusion is faster -along higher concentration gradient -over shorter distances -at higher temperatures -for smaller molecules 5. diffusion ana tan place in an open system or across a partition that separates two systems

Answer 22

6. the rate of diffusion through a membrane is faster if -the membranes surface area is larger -the membrane is thinner -the concentration gradient is larger -the membrane is more permeable to the molecule 7.membrane permeability to a molecule depends on -the molecules lipid solubility -the molecules size -the lipid composition of the membrane

Answer 23

rate of diffusion = surface area x concentration gradient x membrane permeability

Answer 24

membrane permeability= lipid solubility/molecular size changing in the composition of the lipid layer can increase or decrease membrane permeability

Answer 25

O2, CO2, NH3, ect

Answer 26

the majority of molecules in the body are either lipophobic or electrically charged and cannot cross the membrane by simple diffusion -facilitated diffusion or active transport

Answer 27

membrane transport -carrier proteins -channel proteins structural protiens -cell junctions -cytoskeleotn membrane enzymes -metabolism -cell transfer membrane receptors

Answer 28

made of membrane spanning protein subunits that create a cluster of cylinders with a pore through the centre charge and size of the channel determines what is allowed to pass through -named according to the substance that passes through (aqaupourins) -open channels (leaky channels) -gated channels normally closed chemically gated, voltage gated or mechanically gated facilitated diffusion - Open and allow water and ions to follow their concentration gradient or their osmotic gradient

Answer 29

-large complex proteins -change confirmation to move molecules -slow -Don’t create an open pore -protein undergoes a conformational change to move molecules -can move small organic molecules that cannot pass through channels

Answer 30

transport only one kind of substrate

Answer 31

move two or more substrates in the same direction across the membrane

Answer 32

move substrates in opposite directions

Answer 33

-Some molecules and ions appear to move into and out of the cell by diffusion, but based not heir chemical properties cannot be simple diffusion across the lipid bilayer -uses channel or carrier proteins -move down their concentration gradient -no energy required (passive) -stops once equilibrium is reached

Answer 34

-moves molecules against their concentration gradients: from an area of low concentration to an area of high concentration -support a state of disequilibrium (as seen with certain ions) -requires energy -uses carrier proteins

Answer 35

energy to move molecule comes directly from hydrolyzing ATP (refereed to as an ATPase)

Answer 36

uses the potential energy stored in the concentration gradient of one molecule to push another molecule against their concentration gradient

Answer 37

sodium potassium pump calcium ATPase pump

Answer 38

-the majority harness the kinetic energy of Na+ moving down its concentration gradient to move a second molecule against their concentration gradient -can move in the same direction (symport) or opposite direction (anti port or exchanger) -Created through an active transport process this is considered a secondary active transport

Answer 39

refers to the ability of a transporter to move one moleucle or a closely related group of molecule eg. GLUT transporters moves naturally occurring 6 carbon sugars but will not move disaccharide maltose

Answer 40

a carrier may move several members of a related group of substance, but these substances compete with one another -carrier may have a preference for one family member

Answer 41

rate of transport depends on concentration and number of transporters -transport normally increases with increasing concentration until transport maximum is reached (all of the transporters are in use)

Answer 42

macromolecules that cannot fit through a carrier or channel Phagocytosis, endocytosis, exocytosis all use bubble like vesicles created from the cell membrane

Answer 43

creates vesicles using the cytoskeleton 1) the phagocytic white blood cell encounters a bacterium that binds to the cell membrane 2) the phagocyte uses its cytoskeleton to push its cell membrane around the bacterium, creating a large vesicle, the phagosome 3) the phagosome containing the bacterium separates form the cell membrane and moves into the cytoplasm 4) the phagosome fuses with lysosomes containing digestive enzymes 5) the bacterium is killed and digested within the vesicle -requires ATP to move the cytoskeleton for intracellular transport of the vesicle (active transport mechanism)

Answer 44

- membrane indents -vesicles are much smaller also requires ATP

Answer 45

transport into cell non-selective pinocytosis: allows ECF to enter selective receptor mediated transport

Answer 46

vesicles cna be filled with large lipohobic molecules such as proteins synthesized in the cell or wastes left behind by lysosomes after intracellular digestion can occur continuously (goblet cells in the intestine producing mucus) or intermittently when initiated by some sort of signal (hormones) -requires ATP -can be regulated by Ca2+ considered active transport

Answer 47

substances entering and exiting the body often have to cross a layer of epithelial cells (line lumen to surface of organs) -digestive tract, airways, kidneys ect. -from lumen of organ to ECF= absorption -from ECF to lumen of organ = secretion transcellular: across epithelial cells paracellular: between tight junction transcytosis: vesicles

Answer 48

polarized distribution of membrane transporters ensures one-way movement

Answer 49

ex. epithelial glucose transport 1. Na+ glucose symporter brings glucose into cell against its gradient using energy stored in the Na+ concentration gradient 2. GLUT transporter transfers glucose by facilitated diffusion 3. Na+, K+ and ATPase pumps Na+ out of the cell, keeping ICF Na+ concentration low

Answer 50

it does not require energy, substances move down the gradient two types: simple and facilitated diffusion

Answer 51

it does require energy, substance move uphill (against gradient) two types: primary and secondary

Answer 52

it does require energy three types: phase, endo, exocytosis

Answer 53

it sometimes require energy (trans cellular and transcytosis) three types: paracellular, transcellular and transcytosis

Answer 54

many solutes in the body carry a net electrical charge - or + major cation + = intracellular K+ and extracellular Na+ anions - = intracellaur phospahte ions, protiens extracellular CI- the body as a whole is electrically neutral for every carton there is an anion

Answer 55

net amount of charge produced in any process is zero, for every postive charge on an ion there is an electron on another ion

Answer 56

-opposite charges attract -separating positive charges form negative charges requires energy. -the material through which postive and negative charges can move towards one another is a conductor (water) a mortals separating charges is an insulator (membrane)

Answer 57

the electrical disequilibrium that exists between the ECF and the ICF is called the membrane potential difference or membrane potential the combination of electrical and concentration gradient is called electrochemical gradient for any given concentration gradient of a single ion, the membrane potential that exactly opposes the concentration gradient is known as the equilibrium potential

Answer 58

gas constant temperature in kelvin valence faraday constant

Answer 59

the membrane potential of a living cell when it is not active is referred to as the resting membrane potential in living systems we cannot measure absolute charge so we describe electrical gradients on a relative scale

Answer 60

the cell permeable to multiple types of ions due to the presence of open channels and protein transporters resting cells are permeable t both Na+ and K+ but to different degrees -cell membrane is about 40 times more permeable to potassium

Answer 61

Na-K ATPase -sets up concentration gradients that ultimately determine membrane potential 3Na+ 2K+ in electrogenic- generates a negative intracellular charge

Answer 62

1. the contraction gradients of different ions across the membrane 2. the permeability of the membrane to those ions

Answer 63

sodiuma entering = depolarization potassium leaving = hyper polarization C- entering = hyperpolarization