solutions/cell transport

Question 1

what re the 2 major components of the cell membrane?

Answer 1

1. phospholipid molecules

2. proteins

Question 2

what are phospholipids in the structure of the cell membrane, what are the parts?

Answer 2

• double layer of molecules that make up cell membrane
• hydrophilic heads –> polar, group together on the outside layers (bread of a sandwich)
• hydrophobic tails –> non-polar, group together on the inside (fillings of a sandwich), double layer

Question 3

what is a concentration?

Answer 3

the amount of solute in a solvent

Question 4

what is a concentration gradient?

Answer 4

different concentrations of solute (one high, one low), typically separated by a membrane

Question 5

what is a solute?

Answer 5

the component that is dissolved in the concentration

Question 6

what is a solvent?

Answer 6

the liquid component

eg. often water

Question 7

what is a solution?

Answer 7

a solute in a solvent

Question 8

what is diffusion?

Answer 8

Movement of particles from an area of high concentration to an area of low concentration
-movement of solutes

Question 9

what are factors that determine diffusion?

Answer 9

• charge of molecules
• structure
• size
• concentration of gradient

Question 10

what is passive transport?

Answer 10

1. movement of particles down a concentration gradient

2. requires no input of energy –> passive process

Question 11

what do solute concentrations always want to be in?

Answer 11

equilibrium

Question 12

what is simple diffusion, what materials diffuse by simple diffusion?

Answer 12

when substances diffuse down their own concentration gradient through the cell membrane
NOTHING HYDROPHILIC, NOTHING LARGE, NOTHING CHARGED
-lipid-soluble compounds
-dissolved gases
eg. oxygen, CO2

Question 13

what is facilitated diffusion, what materials are moved by facilitated diffusion?

Answer 13

when substances diffuse down their own concentration gradient but proteins are needed to help facilitate movement through cell membrane
-moves molecules that are large, bulky, charged

Question 14

what are the 2 types of diffusion?

Answer 14

1. channel-mediated facilitated diffusion

2. carrier-mediated facilitated diffusion

Question 15

what do channel proteins transport across the cell membrane?

Answer 15

water soluble compounds and ions

Question 16

what do carrier proteins transport across the cell membrane?

Answer 16

molecules that are too large to fit through channel proteins

eg. glucose, amino acids

Question 17

what is an aquaporin?

Answer 17

a channel protein that specifically facilitates movement of water –> osmosis, can move large amounts of water

Question 18

what is osmosis?

Answer 18

movement of water through a semi permeable membrane.

-occurs when membrane is permeable to water, but not to solutes

Question 19

which way does water move across a gradient?

Answer 19

movement of water from:
side with high water concentration –> side with low water concentration
movement of water from:
side with low solute concentration –> side with high solute concentration
“water always wants to be where there is more solute”

Question 20

what is the hypertonic solution?

Answer 20

is the solution with the higher solute concentration

Question 21

what is the hypotonic solution?

Answer 21

is the solution with the lower solute concentration

Question 22

what are isotonic solutions?

Answer 22

when both solutions have the same solute concentration, regardless of volume

Question 23

what will happen to an animal cell if it is put in a hypotonic solution, what is this called?

Answer 23

placed in a hypotonic solution, water will move into the cell (water movement from area of low solute to high solute), which will cause the cell to expand and burst. this is called lysis “lysing the cell”

Question 24

what will happen to an animal cell if it is put in a hypertonic solution, what is this called?

Answer 24

placed in a hypertonic solution, water will move out of the cell (water movement from area of low solute to higher solute), which will cause the cell to shrivel. this is called crenation

Question 25

what will happen to an animal cell if it is placed in an isotonic solution?

Answer 25

nothing, but water will still move by random diffusion

Question 26

what will happen to a plant cell if placed in a hypotonic solution, what is this called?

Answer 26

placed in a hypotonic solution, water will move into the cell (water movement from low solute to higher solute), which will cause the cell to become turgid.

• this is a plants happy place
• will not burst because it has a cell wall to hold it together

Question 27

what will happen to a plant cell is it is placed in a hypertonic solution, what is this called?

Answer 27

placed in a hypertonic solution water will move out of the cell (water movement from low solute to higher solute), and cause the cell membrane to pull away from the cell wall. this process is called plasmoysis.
“the cell has plasmolyzed”

Question 28

what will happen to a plant cell that is placed in an isotonic solution?

Answer 28

plant will lose turgor pressure and will become “flaccid”. no increase in water movement into plant cells, will cause the cells to not be firm (turgid), which effects structural support, and will cause the plant to wilt.

Question 29

what is active transport?

Answer 29

1. movement of particles against concentration gradient
   “making a gradient”
2. uses energy
   cell wants to be in equilibrium, so you need energy to force particles the opposite way they want to go
3. needs carrier proteins
   “pump”

movement of particles using energy, against the concentration gradient with a carrier protein

Question 30

what is co-transport?

Answer 30

moving multiple things into/out of the cell at once
-cell takes advantage of solutes wanting to be in equilibrium and will pump (via active transport) ions out/in and when they return/leave, they bring an additional material with them