Cell Transport and Solutions
Summary
TLDRThis educational video explores the effects of extracellular solution concentration gradients on cellular transport. It explains how cells respond to hypertonic, isotonic, and hypotonic solutions. Hypertonic solutions cause cells to lose water and shrink due to higher solute concentration outside the cell, leading to crenation in red blood cells and plasmolysis in plant cells. Isotonic solutions have equal solute and solvent concentrations as inside the cell, resulting in no net water movement and cell size remaining constant. Hypotonic solutions, with higher water concentration outside the cell, cause cells to swell due to water influx, potentially leading to cytosis or hemolysis. The video uses clear examples and analogies to help viewers understand these concepts.
Takeaways
- 🌟 Cells can be surrounded by solutions with varying particle concentrations, which can be hypertonic, isotonic, or hypotonic relative to the cell's interior.
- 💧 In a hypertonic solution, the external environment has a higher solute concentration and lower water concentration than inside the cell, leading to water loss from the cell through osmosis.
- 🌱 Plant cells respond to hypertonic conditions by losing turgor pressure and undergoing plasmolysis, which causes wilting.
- 🔄 Isotonic solutions have the same concentration gradient as inside the cell, resulting in no net movement of water molecules across the cell membrane, thus maintaining cell size.
- 🌊 Hypotonic solutions have a higher water concentration outside the cell than inside, causing water to enter the cell by osmosis and potentially leading to cell swelling or cytosis.
- 🩸 In red blood cells, the swelling due to hypotonic conditions is known as hemolysis, whereas in plant cells, the rigid cell wall prevents bursting, avoiding cytolysis.
- 🔑 The process of water diffusion across the cell membrane due to concentration differences is called osmosis, which is key to understanding cell response to different solutions.
- 📉 Hypertonic solutions can cause cells to shrivel and potentially implode due to excessive water loss, a phenomenon known as crenation in red blood cells.
- 📈 Hypotonic solutions can lead to cell swelling as water molecules move into the cell to equalize the concentration gradient, with the potential risk of cell bursting.
- 🌿 The rigid cell wall in plant cells provides structural support and prevents the cells from bursting due to water influx in hypotonic conditions, unlike in animal cells.
Q & A
What factors affect the transport of substances through the cell membrane?
-The concentration gradient of extracellular solutions affects the transport of substances through the cell membrane.
What are the three types of solutions that can surround a cell, and how do they differ?
-The three types of solutions are hypertonic, isotonic, and hypotonic. They differ based on the concentration of solutes and water: hypertonic solutions have higher solute concentration and lower water concentration outside the cell, isotonic solutions have equal solute and water concentrations inside and outside the cell, and hypotonic solutions have lower solute concentration and higher water concentration outside the cell.
What happens to a cell when it is in a hypertonic solution?
-In a hypertonic solution, water molecules diffuse out of the cell through osmosis, causing the cell to shrivel. In extreme cases, the cell could shrivel to the point of imploding.
What is the term for the shriveling of red blood cells in hypertonic solutions?
-The term for the shriveling of red blood cells in hypertonic solutions is crenation.
How does a hypertonic solution affect plant cells?
-In plant cells, a hypertonic solution causes water to leave the cell by osmosis, leading to a decrease in turgor pressure and a process called plasmolysis, which causes the plant to wilt.
What is an isotonic solution, and how does it affect the cell?
-An isotonic solution has the same concentration of water and solute as inside the cell, resulting in equal rates of water molecules entering and exiting the cell. This means the cell does not shrink or swell and stays the same size.
What happens to a cell when it is in a hypotonic solution?
-In a hypotonic solution, water molecules move passively into the cell by osmosis until equilibrium is reached, causing the cell to swell. If the water concentration outside the cell is high enough, the cell can swell to the point of bursting, a process called cytosis or hemolysis in red blood cells.
Why don't plant cells burst in hypotonic solutions like animal cells can?
-Plant cells don't burst in hypotonic solutions because their rigid cell walls prevent the cells from bursting due to the increased internal pressure from water intake.
What is the trick to remember the effect of hypotonic solutions on cells?
-The trick to remember the effect of hypotonic solutions is to think of a 'big swollen hippopotamus' or 'hippo' for short, which helps recall that hypotonic solutions cause cells to swell.
How does the concentration of solutes and water in a solution relate to the process of osmosis?
-The concentration of solutes and water in a solution determines the direction of water movement through osmosis. Water moves from areas of lower solute concentration (higher water concentration) to areas of higher solute concentration (lower water concentration) until equilibrium is reached.
Outlines
🌊 Osmosis and Cell Response to Hypertonic Solutions
This paragraph explores how the concentration gradient of extracellular solutions impacts substance transport across cell membranes. It explains that cells can encounter hypertonic, isotonic, or hypotonic solutions relative to their internal environment. Using a beaker of saltwater and a large cell model, the video demonstrates how cells respond to hypertonic solutions, where the external solution has a higher solute concentration and lower water concentration than inside the cell. This causes water to diffuse out of the cell via osmosis, leading to cell shrinkage or crenation in red blood cells and plasmolysis in plant cells, which involves the loss of turgor pressure and wilting.
💧 Isotonic Solutions and Their Effect on Cell Volume
The second paragraph delves into isotonic solutions, where the external solution's solute and water concentrations match those inside the cell. This results in no net movement of water across the cell membrane, as the rates of water entering and exiting the cell are equal. The video uses an example of a cell in an isotonic solution to illustrate that the cell's size remains constant due to the balanced osmotic exchange. The paragraph also contrasts isotonic conditions with hypotonic ones, where the external solution has a higher water concentration, leading to cell swelling through osmosis. It warns that extreme hypotonic conditions can cause cells to burst due to cytosis or hemolysis, except in plant cells, which are protected by their rigid cell walls.
Mindmap
Keywords
💡Cell Membrane
💡Concentration Gradient
💡Hypertonic Solution
💡Isotonic Solution
💡Hypotonic Solution
💡Osmosis
💡Crenation
💡Plasmolysis
💡Turgor Pressure
💡Cytosis
💡Hemolysis
Highlights
The concentration gradient of extracellular solutions affects the transport of substances through the cell membrane.
Cells may respond differently to hypertonic, isotonic, or hypotonic solutions.
Hypertonic solutions have a higher solute concentration and lower water concentration outside the cell compared to inside.
In hypertonic conditions, water diffuses out of the cell causing it to shrivel, a process known as crenation in red blood cells.
Plant cells in hypertonic solutions experience plasmolysis, where the cell membrane shrinks away from the cell wall.
Isotonic solutions have the same concentration gradient as inside the cell, resulting in no net movement of water.
In isotonic conditions, the cell maintains its size due to equal rates of water entering and exiting.
Hypotonic solutions have a higher water concentration outside the cell, leading to water diffusion into the cell and cell swelling.
Cytosis, or cell swelling, can occur in hypotonic solutions, potentially causing cells to burst, a process called hemolysis in red blood cells.
Plant cells do not burst in hypotonic solutions due to the protective rigid cell wall.
A mnemonic for remembering hypotonic solutions is to think of a 'big swollen hippopotamus'.
In isotonic solutions, the water concentration inside and outside the cell remains the same, preventing cell size changes.
Hypotonic solutions cause water molecules to diffuse into the cell by osmosis, leading to swelling.
Hypertonic solutions result in water molecules diffusing out of the cell by osmosis, causing the cell to shrivel and potentially implode.
Plasmolysis in plants is the cell collapse observed in hypertonic solutions.
The video provides a comprehensive overview of how cell size and shape are influenced by the type of extracellular solution.
Transcripts
in this video we'll discuss cell
transport and solutions
the concentration gradient of
extracellular solutions affects the
transport of substances through the cell
membrane
what can happen in this process
well cells may be surrounded by
solutions with different particle
concentrations both in a lab as well as
inside a living organism
so we need to know how cells will
respond
compared to the solution inside a cell a
solution outside the cell may be
hypertonic
isotonic
or hypotonic
we'll describe hypertonic solutions
using this beaker of water with
dissolved salt and a rather large cell
submerged in it
to demonstrate water movement in and out
of cells we'll use simple numbers to
illustrate concepts
remember the cell cytoplasm is mostly
water as well
in this example let's say the cytoplasm
inside the cell is a solution containing
10 percent salt which means the other 90
percent is water
keep in mind percentages of substances
within the cell must equal one hundred
percent
the percentages of solute and solvent in
the beaker must also add up to one
hundred percent
however the solution in the beaker is a
different concentration from the
solution inside the cell
it's 20 salt and 80 percent water
so you can see that there's a greater
concentration of water inside the cell
than outside ninety percent compared to
eighty percent
we call a solution hypertonic when its
concentration of water is lower than
inside the cell and its concentration of
solute is higher than inside the cell
as a result water molecules diffuse out
of the cell through osmosis causing the
cell to shrivel a bit
remember osmosis means diffusion of
water
if the solution's water concentration
was significantly lower the cell could
shrivel to the point of imploding
for red blood cells in hypertonic
solutions the shriveling from osmotic
water loss is called crenation
let's look at an example of plant cells
in a hypertonic solution
normally turgor pressure which is the
water pressure in a plant cell's central
vacuole helps support the cell wall and
overall plant shape
when water leaves plant cells by osmosis
the cell membrane and its contents
shrink away from the rigid cell wall and
turgor pressure decreases
this is called plasmolysis
plasmolysis causes a plant to wilt
let's look at another container this
time with a cell floating in an isotonic
solution
sometimes
the solution outside the cell has about
the same concentration gradient as the
concentration gradient inside the cell
once again in this example the solution
inside the cell is ninety percent water
with ten percent salt
but this time the surrounding solution
is also ninety percent water with ten
percent salt dissolved
we call a solution isotonic when its
concentrations of water and solute are
the same as inside the cell
but this doesn't mean that there is no
movement
in an isotonic solution the rate of
water molecules entering the cell is
equal to the rate of water molecules
exiting the cell
the amount of water molecules going in
equals the amount of water molecules
going out
that's why you see the arrows pointing
in two different directions
in an isotonic solution the cell doesn't
shrink or swell it stays exactly the
same size
a third possibility is a solution
outside the cell with a higher
concentration of water than the solution
inside the cell
in this example the solution inside the
cell has 20 salt so that means the
remainder is 80 percent water
but the cell has been placed in a beaker
that only has a 10 salt solution
doing the math we can see that the
solution surrounding the cell is 90
water which means there's a greater
concentration of water outside the cell
than inside
we call a solution hypotonic when its
concentration of water is higher than
inside the cell and its concentration of
solute is lower than inside the cell
so by osmosis the water molecules will
move passively into the cell until a
state of equilibrium is reached
hypotonic solutions cause a cell to
swell up with water
if the water concentration outside the
cell is high enough the cell can swell
to the point of bursting
this is called cytosis
cytosis in red blood cells is called
hemolysis
cytolysis doesn't happen in plant cells
because the rigid cell wall prevents the
cells from bursting
here's a little trick to remember that
hypotonic solutions cause a cell to
swell rather than shrivel when you think
of hypo think of a big swollen
hippopotamus or hippo for short
so to recap we can have solutions that
are hypertonic isotonic or hypotonic
with respect to the cell
in an isotonic solution the water
concentration inside and outside the
cell stays about the same the water
concentration stays the same because the
concentration of solute is the same
as a result there's equal movement of
water in and out of the cell so the size
of the cell stays the same
here's a hypotonic solution
remember this means that there is a
lower concentration of solute outside
the cell compared to inside the cell
this causes water molecules to diffuse
into the cell remember when diffusion
happens with water we call that osmosis
this causes the cell to swell
if the concentration difference is high
enough cytolysis may occur
finally in a hypertonic solution the
solute concentration outside the cell is
higher compared to inside the cell
so through osmosis water molecules
diffuse out of the cell
this causes the cell to shrivel up and
it can even implode or collapse if
enough water leaves
in plants this cell collapse is called
plasmolysis
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