Biology Lab 4

Question 1

How is the steady state of a cell maintained

Answer 1

regulated movement of materials thru cytoplasm, across organelle membranes, and across the plasma membrane

Question 2

what type of solution is are the cytoplasm and extracellular environment of the cell

Answer 2

aqueous

Question 3

what is a solvent

Answer 3

a dissolving agent
- ex=water

Question 4

what is a solute

Answer 4

dissolved substances

Question 5

are the membranes of organelles and the plasma membrane permeable

Answer 5

they are selectively permeable

Question 6

selectively permeable

Answer 6

allowing water to freely pass through but not regulating the movement of solutes

Question 7

what is ATP

Answer 7

adenosine triphosphate

Question 8

when is ATP used

Answer 8

when the cell actively moves some dissolved substances across membranes

Question 9

how do molecules move in diffusion

Answer 9

move from area of high concentration to area of lower concentration

Question 10

what is the energy that dives diffusion

Answer 10

intrinsic kinetic energy in all atoms and molecules

Question 11

how are some substances able to move passively

Answer 11

ATP is used and only if cell membrane is permeable to those substances

Question 12

is osmosis a form of diffusion

Answer 12

yes; type of diffusion

Question 13

what does osmosis specifically move

Answer 13

water through a selectively permeable membrane
- highly concentrated to lower concentration

Question 14

what causes a difference in the concentration of water in osmosis

Answer 14

if there is an unequal distribution of at least one dissolved substance on either side of a membrane and the membrane is impermeable to that substance

Question 15

osmolarity

Answer 15

solute concentration expressed as molarity

Question 16

tonicity

Answer 16

releative concentration of solutions inside and outside a cell that will determine the direction of water flow
- hypertonic
- hypotonic
- isotonic

Question 17

what kind of solution is hypertonic

Answer 17

solution with greater concentration of solute particles
- water leaves cell

Question 18

what kind of tonecicity causes a cell to shrivel

Answer 18

hypertonic

Question 19

what kind of solution is isotonic

Answer 19

solute concentrations are equal
- water coming in = water leaving

Question 20

what kind of tonicity causes the cell to swell

Answer 20

hypotonic

Question 21

what kind of solution is hypotonic

Answer 21

solution with lower solute particles
- more water is moving into cell than leaving cell

Question 22

why are molecules of a liquid or gas constantly in motion

Answer 22

because of the intrinsic kinetic energy in all atoms

Question 23

what is the driving force of diffusion

Answer 23

intrinsic kinetic energy

Question 24

what is intrinsic kinetic energy

Answer 24

molecular kinetic energy being passed to larger molecules

Question 25

Brownian Movement

Answer 25

random motion of particles suspendered in a medium

Question 26

how does the net flow of water work in cell so freshwater plants and algae in their environment

Answer 26

they are bathed in water containing only dilute concentration of solvents
- water from surrounding environment into the cells

Question 27

what affects the cells response to solutions of different molarities in plants or algal

Answer 27

presence of a cell wall and a large fluid filled central vacuole

Question 28

what happens to a plant cell when it is placed in a hypertonic solution

Answer 28

water moves out of the cell
- protoplast shrinks and moves away from cell wall

Question 29

what is the process called when protoplast shrink and move away from the cell wall

Answer 29

plasmolysis

Question 30

what happens to a plant when it is placed in a hypotonic solution

Answer 30

water moves into cell and into cell’s central vacuole and the protoplast expands

Question 31

what is a protoplast

Answer 31

the plant cell exclusive of the cell wall
- the cytoplasm enclosed by plasma membrane

Question 32

turgor pressure

Answer 32

pressure of the protoplast on the cell wall owing to uptake of water

Question 33

what happens when there is high turgor pressure

Answer 33

prevent further movement of water into the cell

Question 34

how does turgor pressure relate to hypertonic conditions

Answer 34

turgor pressure begins to force water through the membrane and out of the cell

Question 35

in plants, what is needed to for normal activities to take place

Answer 35

amount of water relative to solute concentration in cell must be maintained within a reasonable range

Question 36

what was one of the objects for part 4.3

Answer 36

find the molarity at which weight of the potato tuber tissue does not change, indicating that there has been no net less or gain of water