John Bowne High School





Cell transport

Vocabulary:

Concentration gradient is a difference in the concentration (or amount) of a substance across a distance.

Diffusion is the movement of particles from a region (area) of high concentration of a substance to region (area) of low concentration.

Equilibrium is a condition or state that exists when things are balance or equal.

Osmosis is the diffusion of water through a semi-permeable membrane from an area of high concentration to an area of low concentration of water.

Solution is a mixture of solvent and solute.

Solvent is the liquid portion of a solution. Ex: water

Solute is the particle portion of a solution. Ex: Na+ ion, Cl- ion, glucose molecule, salt, etc.

Carrier protein is a protein that transports substances across a cell membrane.

Sodium-potassium pump is a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell.

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How does simple diffusion differ from facilitated diffusion?

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PASSIVE TRANSPORT - TAKING THE EASY ROAD

While active transport requires energy and work, passive transport does not. There are several different types of this easy movement of molecules. It could be as simple as molecules moving freely such as osmosis or diffusion. You may also see proteins in the cell membrane that act as channels to help the movement along. And of course there is an in-between transport process where very small molecules are able to cross a semi-permeable membrane.

Sometimes, proteins are used to help move molecules more quickly. It is a process called facilitated diffusion. It could be as simple as bringing in a glucose molecule. Since the cell membrane will not allow glucose to cross by diffusion, helpers are needed. The cell might notice outside fluids rushing by with free glucose molecules. The membrane proteins then grab one molecule and shift their position to bring the molecule into the cell. That's an easy situation of passive transport because the glucose is moving from higher to lower concentration. It's moving down a concentration gradient. If you needed to remove glucose, the cell would require energy.

LETTING CONCENTRATION DO THE WORK

Sometimes cells are in an area where there is a large concentration difference. For example, oxygen molecule concentrations could be very high outside of the cell and very low inside. Those oxygen molecules are so small that they are able to cross the lipid bilayer and enter the cell. There is no energy needed for this process. In this case, it's good for the cell because cells need oxygen to survive. It can also happen with other molecules that can kill a cell.

OSMOSIS

Another big example of passive transport is osmosis. This is a water specific process. Usually, cells are in an environment where there is one concentration of ions outside and one inside. Because concentrations like to be the same, the cell can pump ions in an out to stay alive. Osmosis is the movement of water across the membrane.

For a cell to survive, ion concentrations need to be the same on both sides of the cell membrane. If the cell does not pump out all of its extra ions to even out the concentrations, the water is going to move in. This can be very bad. The cell can swell up and explode. The classic example of this type of swelling happens when red blood cells are placed in water. The water rushes in to the cells, they expand and eventually rupture (POP!).

ACTIVE TRANSPORT - ENERGY TO TRANSPORT

Active transport describes what happens when a cell uses energy to transport something. We're not talking about phagocytosis (cell eating) or pinocytosis (cell drinking) in this section. We're talking about the movement of individual molecules across the cell membrane. The liquids inside and outside of cells have different substances. Sometimes a cell has to work and use some energy to maintain a proper balance of ions and molecules.

PROTEINS IN THE MEMBRANE

Active transport usually happens across the cell membrane. There are thousands of proteins embedded in the cell's lipid bilayer. Those proteins do much of the work in active transport. They are positioned to cross the membrane so one part is on the inside of the cell and one part is on the outside. Only when they cross the bilayer are they able to move molecules and ions in and out of the cell. The membrane proteins are very specific. One protein that moves glucose will not move calcium (Ca) ions. There are hundreds of types of these membrane proteins in the many cells of your body.

Many times, proteins have to work against a concentration gradient. That term means they are pumping something (usually ions) from areas of lower to higher concentration.

QUESTIONS

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Q1. Which type of transport is shown in the above picture? Give 2 reasons to support your answer.

Ans1. ________________________________

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Q2. Which type of transport is shown in the above picture?

Ans2.

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Q3. Which process is depicted in the above picture? Justify your answer with an explanation.

Ans3. ___________________________________________________________________________________________

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Q4. Which type of transport is shown in the above picture? Give 2 reasons to support your answer.

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Q5. Which type of transport is shown in the above picture? Give 2 reasons to support your answer.

Ans5. ___________________________________________________________________________

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What are two likely reasons a Cl- ion cannot pass through a sodium ion channel?

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What happens to a carrier protein when a molecule outside the cell binds to it?

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Q1. Draw the direction of movement of water molecules in the box.

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Q2. Identify the process that caused the movement of water molecules.

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Apply the reading code to the following chart and put a check on the solution you understand the best.

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Q. A cell is placed into a hypertonic solution. How does the concentration of water differ in the solution and the cell cytoplasm?

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Q. Which side of the following diagram is showing passive transport and which side is active transport?

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So it seems that proteins are there in the cell membrane to do a few things…

Besides playing role in facilitated diffusion, proteins help in active transport across the cell membrane!

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If H+ ion is being transported by active transport, draw an arrow on the above picture to show the direction of transport.

Why do cells need active transport?

What is the role of ATP in active transport? [pic]

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And what happens if cell needs a lot of stuff in or out, all at once?

Well, then it will transport it by endo- and exocytosis!

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What is the role of vesicle in endocytosis and exocytosis?

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The diffusion of water through a selectively permeable membrane is called osmosis.

Q1-How are diffusion and osmosis related?

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Simple and complex carbohydrates (sugars and starches)

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How are sugars (glucose and sucrose) different from starch?

How can you tell which food has glucose and which has starch?

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Aim: How does transport happen across the cell membrane?

Or

How do things move in and out of the cell?

Standard 4

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Common Core Learning Standards for Literacy in History/Social Studies, Science, and Technical Subjects.

RST.11-12.4, RST.11-12.7, WHST.11-12.2a, WHST.11-12d, WHST.11-12.4.

INSTRUCTIONAL MODIFICATIONS FOR ELL/SP, ED, STUDENTS (IF APPLICABLE)

1-Provide dictionaries/glossaries

2-Provide alternate reading/writing material to differentiate task

3-Provide extra scaffolding for vocabulary attainment

4-Provide extra wait time for oral response to questions

5-Use of graphic organizers

6-Use more visuals through technology

- Instructional objectives: In addition to being provided with the opportunity to read, write, and speak in order to increase literacy….SWBAT

Objectives:

-Explain key vocabulary words

-Explain concentration gradient

-Explain passive transport

-Explain the concept of diffusion: simple diffusion & facilitated diffusion

-Explain channel protein & carrier proteins

-Explain an indicator

-Explain the concept of osmosis & semi-permeable membrane

-Explain active transport

-Explain endocytosis & exocytosis

Key Questions:

-What is a concentration gradient?

-What is passive transport?

-How does simple diffusion differ from facilitated diffusion?

-When does diffusion stop?

-Why can oxygen pass through the cell membrane by simple diffusion?

-What are two likely reasons a Cl- ion cannot pass through a sodium ion channel?

-What happens to a carrier protein when a molecule outside the cell blinds to it?

-What is osmosis?

-In which direction does water move when a cell is placed into a hypotonic solution?

-A cell is placed into a hypertonic solution. How does the concentration of water differ in the solution and the cell cytoplasm?

-What is active transport?

-Why do cells need active transport?

-What is the role of ATP in the sodium-potassium pump?

-What is the difference between endocytosis & exocytosis?

-What is the role of vesicle in endocytosis & exocytosis?

Assessing students’ prior knowledge, understanding, and misconceptions: (5-8 min)

Do Now: Write a sentence or more

Explain what is the major function of the cell membrane

Or

Explain what is a concentration gradient

Or

Expain the difference between active & passive transport

Aim: How does diffusion happen in a semi-permeable membrane?

Motivation/context: Show short Video

1-Plasma membrane (last 3 min), 2-Transport through cell membrane #2 (2 min), Passive & active transport through cell membrane (1 min).

Introduction of understanding (associate the new understanding with prior knowledge) (10-20 min)

-Reading comprehension “ out- loud” on “ What is a concentration gradient?” and underlining essential parts of reading, use smart board too.

-Solve problem question #3, #4,

Development of lesson (10-20 min)

-Reading comprehension “out-loud” on “What is Passive transport?” and underlining essential parts of reading, use smart board too.

-Solve problem on worksheet: How does simple diffusion differ from facilitated diffusion?

Check Point(s) Have students report to each other and /or to the entire class what they have learned as a check on the progress of the teaching by writing on the smart board. Ask key questions during the check point. (5 min)

Further development of lesson

Use page #2 for analyzing diagrams & reading comprehension “silently & out-loud” on simple & facilitated diffusion.

Underline essential parts in the reading section.

-Solve problem on worksheet:

-Problem question #5, #6, #7, #8

-What are two likely reasons a Cl- ion cannot pass through a sodium ion channel?

-What happens to a carrier protein when a molecule outside the cell binds to it?

Check Point(s) Have students report to each other and /or to the entire class what they have learned as a check on the progress of the teaching by writing on the smart board. Ask key questions during the check point. (5 min)

Homework: Rewrite all underline essential parts of the reading comprehension section.

Aim: How does diffusion & osmosis happen in a semi-permeable membrane?

Assessing students’ prior knowledge, understanding, and misconceptions: (5-8 min)

Do Now: Write a sentence or more

Explain what is a concentration gradient?

Or

Explain the direction of movement in diffusion

Or

Explain the direction of movement in osmosis

Motivation/context: Show short Video

1-Osmosis through membrane #4, 2-Plasma membrane (last 3 min), 3-Transport through cell membrane #2 (2 min),

4-Passive & active transport through cell membrane (1 min).

Introduction of understanding (associate the new understanding with prior knowledge) (10-20 min)

-Reading comprehension “ out- loud” on “What is Osmosis?” and underlining essential parts of reading, use smart board too. In this section explain an “indicator” too.

Or

-Reading comprehension “out-loud” on page 6

-Solve problem questions: #11

Development of lesson (10-20 min)

-Explain the vocabulary words of solute, solvent, & solution.

-Explain hyper, hypo, & iso-tonic solution in the process of osmosis.

-Analyze diagrams on page 3 and label & explain water concentration, & movement of it in osmosis.

-Reading comprehension out-loud on solution chart page 3.

-Solve problem questions on worksheet:

-In which direction does water move when a cell is placed into a hypotonic solution.

-A cell is placed into a hypertonic solution. How does the concentration of water differ in the solution and the cell cytoplasm?

Or

Answer all question on page 6

Check Point(s) Have students report to each other and /or to the entire class what they have learned as a check on the progress of the teaching by writing on the smart board. Ask key questions during the check point. (5 min)

Further development of lesson

-Explain what is an indicator

-Solve problem questions #9, #10, #12, #13

Check Point(s) Have students report to each other and /or to the entire class what they have learned as a check on the progress of the teaching by writing on the smart board. Ask key questions during the check point.

Homework: Rewrite all of essential underline notes & summarize video “osmosis through a membrane #4”.

Or

Summarize video plasma membrane, transport through cell membrane, passive & active transport through cell membrane.

Aim: How does active transport happen across a semi-permeable membrane?

Assessing students’ prior knowledge, understanding, and misconceptions: (5-8 min)

Do Now: Write a sentence or more

-Explain how energy is made in the cell & what is it used for

Motivation/context: Show short Video

-Passive & active transport through cell membrane

-Endocytosis & exocytosis = pinocytosis

Introduction of understanding (associate the new understanding with prior knowledge) (10-20 min)

-Explain active transport is against a concentration gradient that use energy

Development of lesson:

-Reading comprehension on “what is active transport?” & analyze diagrams on page 4

-Answer key questions:

-Why do cells need active transport?

-What is the role of ATP in the sodium-potassium pump?

-Question #1, #2

Check Point(s) Have students report to each other and /or to the entire class what they have learned as a check on the progress of the teaching by writing on the smart board. Ask key questions during the check point.

Further development of lesson

-Explain the difference between endocytosis and exocytosis

-Key question: What is the role of vesicle in endocytosis & exocytosis?

-Summarize transport of material through the membrane by solving the problems on page 5 & 6.

Homework:

-Rewrite all essential underline note and summarize video endocytosis and exocytosis.

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