chp 7 cells and membranes'

Question 0

define osmosis

Answer 0

the diffusion of water

Question 1

define Diffusion

Answer 1

the directional movement of any substance so tht they can spread out into available space.

Question 2

define Hypotonic

Answer 2

Hypotonic: (meaning less solutes)(More H2O) lesser concentration of solutes

Question 3

define isotonic

Answer 3

same concentration

Question 4

define hypertonic

Answer 4

Hypertonic:(meaning more solutes)(Less H2O) greater concentration of solutes

Question 5

define concentration gradient

Answer 5

the region along which the density of a chemical substance increases or decreases .
A substance will diffuse from higher concentration to lower concentration to achieve equilibrium

Question 6

define osmoregulation

Answer 6

the control of solute concentrations and water balance

Question 7

define plasmolysis

Answer 7

As the plant cell shrivels, its plasma membrane pulls away from the cell wall at multiple places.

Question 8

define facilitated diffusion

Answer 8

Many polar molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with help of transport proteins tht span the membrane.

Question 9

define active transport

Answer 9

the transport protein tht move solutes against the concentration gradient are all carrier proteins rather than channel proteins.

Question 10

define membrane potential

Answer 10

The voltage across the membrane

Question 11

define proton pump

Answer 11

which actively transports protons out of the cell

Question 12

define exocytosis

Answer 12

the cell secretes certain molecules by the fusion of vesicles with the plasma membrane

Question 13

define endocytosis

Answer 13

the cell takes in molecules and particulate matter by forming new vesicles from the plasma membrane

Question 14

define sodium-potassium pump

Answer 14

One way ATP can power active transport is by transferring its terminal phosphate grp directly to the transport protein. Thus changing the shape of the protein. exchanging Na+ for K+ across the plasma membrane.

Question 15

define electrochemical gradient

Answer 15

2 forces drive the diffusion of ions across a membrane.
Chemical force - the ions concentration gradient
Electrical force - the effect of the membrane potential on the ions movement.’
the combinations of forces acting on an ion is the electrochemical gradient

Question 16

define transport proteins

Answer 16

specific ions and a variety of polar molecules cant move through cell membranes on their own.
These hydrophilic substances can avoid contact w/ the lipid bilayer by passing through transport proteins

Question 17

define selective permeability

Answer 17

it allows some substances to cross it more eaily than others

Question 18

define phagocytosis

Answer 18

a type of endocytosis in which a lg or small organism is taken up by a cell

Question 19

define pinocytosis

Answer 19

a type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes

Question 20

define receptor-mediated endocytosis

Answer 20

the movement of specific molecules into a cell by the infolding of vesicles containing proteins w/ receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

Question 21

in the fluid mosaic model which part is the fluid and which part is the mosaic?

Answer 21

the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids

Question 22

explain the movement of different molecules across the plasma membrane.
Through what part of the membrane does each type of molecule pass?

Answer 22

small molecules tht are nonpolar are hydrophobic. they can dissolve in the lipid bilayer of the membrane and cross it.
ions move across the membrane in both directions crossing the transport proteins.
polar molecule can cross the membrane through transport proteins.
Sugars, Amino Acids, and other nutrients enter the cell and metabolic waste products leave it.
disaccharides have to b broken down by lysosomes to be able to cross the membrane through the transport protein.

Question 23

list the 6 functions of membrane associated proteins

Answer 23

1) Transport proteins (gates) -
2) Enzymes -
3) Receptors - cell-cell recognition
4) Cell-cell recognition
5) intercellular joining (unit 2 cells together)
6) attachment to cytockeleton / ECM

Question 24

compare and contrast Facilitated diffusion, active transport and co-transport

Answer 24

Facilitated diffusion - helps pass polar molecules and ions through the membrane by a transport protein.
Active transport - exerts energy to pump a solute across a membrane against its gradient.
Co-transport- a transport prortein can couple the “down hill” diffusion of a solute to the “uphill” transport of a second substance against its own concentration gradient.

Question 25

how can the cell wall of plants deal w/ hypo and hypertonic environments?

Answer 25

in a hypotonic solution (bathed in rain) the cell wall helps maintain the cells water balance. cells hav a relatively inelastic wall so when the wall cannot take in any more water the cell is turgid(very firm) this is a healthy state for a plant.
hypertonic the cell wall of a plant has no advantage it will lose its water to its surroundings and shrink.

Question 26

what is the function of membrane sugars? how do they affect human blood grps?

Answer 26

Function - cell identification or classification

affect on blood grps - specific variations of carbohydrates attached to the cell membrane