CELL TRANSPORT Tomato plant must take in nutrients from the soil. Potassium Nitrogen Phosphorus...
-
Upload
anissa-manning -
Category
Documents
-
view
217 -
download
0
Transcript of CELL TRANSPORT Tomato plant must take in nutrients from the soil. Potassium Nitrogen Phosphorus...
CELL TRANSPORT
Tomato plantmust take in nutrientsfrom the soil.
Potassium
Nitrogen
Phosphorus
Every living cell exists in a liquid environment.
One of the most important functions of the cell membrane is to keep the cell’s internal conditions relatively constant.
INFoodGlucoseO2H2O
OUTWasteHormoneCO2H2O
What structure in the cell regulates what substances enter the cell?
The cell membrane regulates and controls which substances enter and leave the cell.
There are two basic methods by which substances enter/exit the cell:
(1) Passive transport --- no energy needed
(2) Active transport --- requires energy
Passive transport is the movement of substances across a cell membrane from an area of higher concentration to an area of lower concentration. (requires no energy )
aasugar saltO2
Higher Concentration
Lower Concentration
InsideCell
What are some characteristics of the cell membrane?
Outside Cell
Nonpolar---oily
InsideCell
Small nonpolar substances such as CO2, O2, and small lipids can pass through the cell membrane by diffusion.
lipidsCO2 O2
Outside Cell
Diffusion is the movement of substances from a region of higher concentration to a region of lower concentration.
High Conc
Low Conc
Low Conc
Low Conc
higher conc lower conc
Equilibrium is the condition in which the concentration of a substance is equal throughout a region. Even at equilibrium, molecules continue to move randomly.
Which way will fat move?
inside cell
outside cell
fat
fat
fat fat
fatfat
fat
fat
fat
fatfat
LOW
HIGH
fatfat
fat
fat
fat fatThat’s diffusion!
InsideCell
How do polar molecules like glucose get across the nonpolar membrane?
Outside Cell
Nonpolar--oily
glucoseglucose
glucose
By Facilitated Diffusion
Channel Proteins
Facilitated Diffusion: The diffusion of substances across the cell membrane through channel proteins. passive
transportNo energyinput
substance substance
higherconc
lowerconc
InsideCell
Proteins in the cell membrane create channels making it easy for certain molecules to pass.
Channel Proteins
glucose glucose
InsideCell
Outside Cell
Polar molecules like glucose diffuse across the membrane by moving through pores formed by channel proteins.
Channel Proteins
glucose glucose
OsmosisWater is very important, so we talk about water separately.
Cell survival depends on balancing water uptake & loss.
freshwater balanced saltwater
Normal plant cell
******
Osmosis is the movement of water across a cell membrane from a region of higher conc to a region of lower conc.
Osmosis is the diffusion of water across a cell membrane.
high concH2O
low concH2O
Cell
mem
bran
e
high concH2O
low concH2O
Cell
mem
bran
e
How does water move?
Always from an area of higher concentration to an area of lower concentration.
The direction of osmosis depends on the relative concentration of solutes on the two sides of the membrane.
low conc solute high conc solute Less watermore water
solute
How does water move?
low conc solute high conc solute Less watermore water
solutemore water less water
Cells are always surrounded by some kind of solution.
The solution surrounding cells may be: (1) isotonic (2) hypotonic (3) hypertonic
An isotonic solution has the same concentration of solute molecules as the cell.
iso = same10 %solute
10 %solute
Water moves in and out at the same rate
iso = same2 %salt
2 %salt
isotonic solution
iso = same5 %glucose
5 %glucose
isotonic solution
A hypotonic solution has a lower concentration of solutes than a cell. This means the concentration of water is greater outside the cell than inside.
Water will move intothe cell
Hypo = more water
10 %solute
25 %solute
The cell will swell.
Less solute
1 %salt
5 %salt
hypotonic solution
1 %glucose
2 %glucose
hypotonic solution
A hypertonic solution has a higher conc of solutes than a cell.
The water conc is lower outside the cell than inside.
Water will move out of the cell
The cell will shrivel.
25 %solute
5 %solute
Hyper = less water more solute
5 %salt
2 %salt
hypertonic solution
3 %glucose
1 %glucose
hypertonic solution
Summing Up!Passive Transport:
Movement from high to lowNo energy
Examples: diffusion facilitated diffusion
osmosis
Contractile vacuole in Paramecium