Write in your notes:I can describe different cellular processes and how they are important for homeostasis.

Science Starter1. What type of cell is pictured to the right?      A. bacteria  B. plant        C. multi-celled     D. animal 

2. What is one of the main functions of the nucleus      of an animal cell? A. It captures sunlight to produce food. B. It is the place where energy is produced for the          animal. C.     It defends the cell from infections. D.     It stores the genetic information of the animal. 

3.    Which of the following organelles is most important in providing energy to a cell? 

        A. mitochondrion       B. nucleus  C. vacuole  D. cell membrane 

Science Starter

4.  What function does the membrane perform in an animal cell? A. contains the genetic material of the cell B. helps control transport of material into and out of the cell C. captures sunlight to produce food D. provides a rigid shape to the cell

5. If you used a peach as a model of an animal cell, what would the peach’s skin represent? 

       A. nucleus B. cell membrane C. cell wall D. cytoplasm

Science Starter1. What type of cell is pictured to the right?      A. bacteria  B. plant        C. multi-celled     D. animal 

2. What is one of the main functions of the nucleus      of an animal cell? A. It captures sunlight to produce food. B. It is the place where energy is produced for the          animal. C.     It defends the cell from infections. D.     It stores the genetic information of the animal. 

3.    Which of the following organelles is most important in providing energy to a cell?         A. mitochondrion       B. nucleus          C. vacuole  D. cell membrane 

Science Starter

4.  What function does the membrane perform in an animal cell? A. contains the genetic material of the cell B. helps control transport of material into and out of the cell C. captures sunlight to produce food D. provides a rigid shape to the cell

5. If you used a peach as a model of an animal cell, what would the peach’s skin represent? 

       A. nucleus          B. cell membrane          C. cell wall          D. cytoplasm

All living things must be able to obtain food and eliminate waste.

Cells can obtain food and eliminate waste through two primary ways:Passive Transport andActive Transport.

What cell structure is responsible for the passage of substances in and out of a cell?

The Cell or Plasma Membrane!

Cells need to perform these tasks in order to maintain homeostasis. This is the tendency of a system to maintain internal equilibrium or balance.

PASSIVE TRANSPORTOsmosis is the process where liquids are able to pass through a membrane (like a cell membrane). Cell membranes are semi-permeable, meaning they allow only water and certain molecules that are dissolved in the water to pass through the cell membrane. Oxygen and carbon dioxide gases both dissolve in water and can move back and forth through the cell membrane with the water. Because so much water, oxygen, and carbon dioxide are constantly passing into and out of a cell, it would totally exhaust the cell if the cell had to use its own stored energy (in the mitochondria) for osmosis. Luckily for the cell, osmosis is a type of passive transport. This means that the cell exerts no energy during osmosis.

http://www.brainpop.com/science/cellularlifeandgenetics/passivetransport/

DiffusionWhen we drop a tea bag or a lump of sugar in a cup of hot water, what happens?

The particles of tea or sugar start to spread out in the water.Spray the air freshener in the far corner of the room. Ask the students in the near corner to indicate when they are able to smell the scent.

Particles do not usually like to be crowded together. When a tight group of particles is released into a liquid or air the particles start to spread out. They move from an area of high concentration to an area of low concentration. That’s why you can smell the air freshener a few minutes after it is sprayed in the opposite corner. This process is known as diffusion.

When the concentration of the dissolved particles (indicated by a %) is greater outside the cell than it is inside the cell, it is a hypertonic solution.

The prefix hyper means “excessive” or “above normal.”

Think (but don’t act) about hyperactivity.

When the concentration of the dissolved particle (indicated by a % is greater inside the cell than it is outside the cell, it is a hypotonic solution.

The prefix hypo means “under” or “below normal.”

If hypo means “below normal” and therm means “heat”, what is a person suffering from if she has hypothermia?Think of (if you dare) a hypodermic

needle. Needles go “under” or “below” your skin. Since water will want to move into the cell, think of the needle injecting it in in a hypotonic situation.

When the concentration of the solution inside and outside the cell is the same, the cell has reached equilibrium, and the solution is called an isotonic solution. Cells like to be balanced. When cells are at equilibrium, water flows in and out of the cell at the same rate. How many of you wear contacts?

Saline solution is designed to have the same concentration of dissolved particles as the cells of your body. If it was too concentrated it would dry your membranes out. If it wasn’t concentrated enough it could cause membranes to swell.

Earlier we learned that an imbalance in the concentrations inside and outside the cell can cause problems. Unlike particles which are antisocial and don’t want to hand out with others, water is a party animal. If the particles can’t come to the water, the water will go to the particles. Water will always try to move to the area where the concentration of particles (example salt) is the greatest.

water

salt

Salt concentration outside the cell higher .

Salt concentration inside the cell higher .

Cells detest imbalance. They work best when the concentration outside the cell and inside the cell are balanced so that water moves in AND out of the cell at the same rate.

Learning Challenge: 1

The left U-pipe is separated in the middle by a semi-permeable membrane. The round black shapes represent salt molecules. Describe (in writing) the cellular process that resulted in the illustration on the right. REMEMBER to USE THE LANGUAGE OF THE LESSON!

start After 1 minute

Solution

The salt particles are too big to diffuse through this membrane. Water moves through the semi-permeable membrane to the area of the highest concentration (the right side of the tube.) This causes the water level on that side of the U-tube to rise. 

Learning Challenge: 2

Amari is body surfing at Tybee after a big storm. He gets pulled under and inhales a lot of water. The cells lining the lungs will not accept more salt into the cell. The average salinity (salt content) of the ocean is 3.5%. The average salinity of our blood is just under 1%.

This is a hypertonic situation because the concentration of salt in the water outside the lung cells (in the fluid surrounding the lung cells) is much higher than the concentration of salt inside the lungs cell. In order to reach equilibrium, water will leave the cells and enter the lung cavity. This causes the lung cavity to fill with fluid and the lungs cannot work properly. You can end up suffocating because you cannot take a deep enough breath to get the oxygen you need nor can you exhale and get rid of the carbon dioxide that is poisoning your body.

HO

Explain (in writing) or illustrate the physical process that will take place in the lungs when a person inhales a large amount of seawater.

Woman dies after water-drinking contest 1/13/2007 10:24:31 PM ET NBCNews.com Jennifer Strange, 28, was found dead Friday in her suburban Rancho Cordova home hours after taking part in the “Hold Your Wee for a Wii” contest in which KDND 107.9 promised a Nintendo Wii video game system for the winner. “She said to one of our supervisors that she was on her way home and her head was hurting her real bad,” said Laura Rios, one of Strange’s co-workers at Radiological Associates of Sacramento. “She was crying and that was the last that anyone had heard from her.” It was not immediately know how much water Strange consumed. A preliminary investigation found evidence “consistent with a water intoxication death,” said assistant Coroner Ed Smith. John Geary, vice president and marketing manager for Entercom Sacramento, the station’s owner, said station personnel were stunned when they heard of Strange’s death. “We are awaiting information that will help explain how this tragic event occurred,” he said. Initially, contestants were handed eight-ounce bottles of water to drink every 15 minutes. “They were small little half-pint bottles, so we thought it was going to be easy,” said fellow contestant James Ybarra of Woodland. “They told us if you don’t feel like you can do this, don’t put your health at risk.” Ybarra said he quit after drinking five bottles. “My bladder couldn’t handle it anymore,” he added. After he quit, he said, the remaining contestants, including Strange, were given even bigger bottles to drink. “I was talking to her and she was a nice lady,” Ybarra said. “She was telling me about her family and her three kids and how she was doing it for kids.” © 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Let’s read this together and YOU develop a hypothesis about the cause of the woman’s death. (Illustration or written explanation.)

Learning Challenge: 3

Explanation

The woman died from a condition known as hyponatremia, which translates to “not enough salt.” The woman drank so much water that the salt concentration of the fluid outside cells became lower than the salt concentration inside the cells. Under normal (isotonic) conditions, the concentration inside and outside the cell is balanced, so water flows into and out of the cell at the same rate. Once the concentration of the solution in the fluids outside the cell dropped below the concentration of the fluid inside the cell, water began to flow into the cell at a higher rate. This caused the cells to swell and in many cases burst. This swelling of cells is most dangerous in the brain. Most cells in the body have room to swell a bit. Brain cells, however, are packed inside a rigid skull and have almost no room to expand. Brain swelling due to hyponatremia can result in severe headaches, vomiting, blot clots (from pieces of blown up cells) which lead to stroke, seizures, coma, and even death.

http://www.scientificamerican.com/article.cfm?id=strange-but-true-drinking-too-much-water-can-kill

Learning Challenge: 4

One of the most damaging aspects of hurricanes is coastal flooding. The storm surge carries vast amounts of seawater (2.5-3.5% salinity) inland. This seawater soaks into the soil. Using your knowledge of how water moves into and out of cells to hypothesis how this can affect plants in the flood zone (written explanation or illustration.) REMEMBER to USE THE LANGUAGE OF THE LESSON!

Solution: Salt water flooding pulls water out of plant roots. If enough roots dry severely enough, the plant can die. Root damage on surviving plants can make them less drought-tolerant in coming years, simply because the plants have fewer living roots with which to take up water.

The longer the water stands around the roots, the more desiccation and the worse the damage is likely to be. The salt can be rinsed out of the soil with repeated irrigation with fresh water. This is best done immediately after the flood recedes, but should be done as soon as possible.

The sodium in salt water also damages soil structure, destroying soil aggregates and impairing the function of the soil. This effect is less of a problem in sandy soil, because sand doesn’t have much structure to start with, but it can be

Learning Challenge: 5

Demonstrate either by drawing or by written explanation the effects of drinking seawater in an attempt to rehydrate. Remember, the ocean has about 3.5% salinity, blood 1-1.5% salinity.

The salinity of the seawater is about 3.5%. The salinity of blood is about 1%. Therefore, the concentration of salt in the stomach after drinking the seawater would be much higher than the concentration of salt in the blood vessels lining the stomach and small intestines. Water would leave the blood cells for the area of higher concentration. Drinking seawater actually decreases the amount of water in your blood causing even greater dehydration.

So, what about Bear Gryllis drinking his own urine to survive. Isn’t urine (like sweat) salty?

Yes…but it’s salinity is usually around 2%. Your body can deal with that and urine is usually sterile….It is safer to drink than the water in most developing nations.

Learning Challenge: 6

After a heavy rain, Farmer McDougal’s tomatoes always split. Explain in writing or by illustrating why this splitting occurs.

Hint: rainwater is usually very close to “pure,” meaning it has few if any dissolved particles.

ACTIVE TRANSPORT

http://www.brainpop.com/science/cellularlifeandgenetics/activetransport/preview.weml Brainpop: Active Transport

Some molecules or particles of food are too big to pass through the cell membrane. In these instances, the cell actually has to open a part of the cell membrane. This requires the cell to use some of its stored energy, so it is no longer passive transport. When the cell has to use some of its energy to move things in and out of the cell, it is called active transport.

.

When large particles of food are taken into the cell, it is called endocytosis.

The prefix endo- means “to go into.” Think ENdo-Enter.

When the cell releases large bundles of waste from the cell, that is called exocytosis.

The prefix exo- means “out of” or “outer.” Think ExoExit.

Steps of Endocytosis                        

During endocytosis, the cell membrane folds inward and fuses together. This surrounds the substance in a pocket.

The pocket pinches off inside of the cell, forming a vesicle.

The vesicle fuses with a lysosome or similar vesicle. Then, enzymes break down the membrane AND the contents inside!

Steps of Exocytosis                      

The cell forms a vesicle around material that needs to be expelled from the cell.

The vesicle is transported to the cell membrane.

The vesicle membrane fuses with the cell membrane and releases the contents from the cell.

Diffusion

Osmosis

Active Transport

Movement of small molecules across the membrane

No energy,High to low concentration

Move molecules in and out of cell

Uses energy while moving molecules across the cell, moves from low to high concentration

Movement of water across the membrane

http://www.youtube.com/watch?v=Svbf40z5obE&list=PLC8DA5F7B89FEEABD&index=55optional Mr. Parr

1. _________________________ is the process where water and certain dissolved particles like CO2 and H20 pass through the cell membrane into and out of the cell.

2. _________________________ refers to the tendency of particles to disperse (spread out) in a liquid or in air.

3. What transport process does the diagram directly below illustrate?__________________________________

4. Is this active or passive transport?

Osmosis

Diffusion

Exocytosis

Active Check for Understanding A

5. In the diagram below, which test tube must contain the red blood cell in salt water and which one must contain the red blood cell in distilled (purified) water.

6. In the diagram to the below, water is leaving the cell. Explain why (Na+is sodium, a sodium ion.)

distilled

Salty

The concentration of dissolved sodium is greater outside the cell than inside. Water flows to the area of highest concentration.

7. Which two cellular processes are taking place in this image?

Start 30 sec 1 min

Molecules dissolved in water spread out (diffusion) and are able to pass through the membrane in the water (osmosis.)

8. Endocytosis is a type of ____________________ transport because the cell has to use some of its energy to release larger particles from the cell. 9. Osmosis is a type of _______________________ transport because no energy is required by the cell to move water and solutes in and out of the cell.  10. One of the roles of our large intestine is to absorb excess water from our waste. This water is able to pass through the cell membranes of the large intestine and the blood cells that carry the water back into the body. What process allows the water to move through the cell membranes?

11. Sid is conducting a scientific experiment on osmosis. He places a blueberry in a test tube with a 35% solution of salt water. What will happen to the blueberry?_________________________________________

active

passive

Osmosis

Water will leave the blueberrycausing it to shrink.

12. A cell’s plasma membranes are semi-permeable. What does that mean?

They allow some molecules to pass through but not others that are larger.

13. The diagram below illustrates the exchange of carbon dioxide and oxygen gases in the lungs (both of which are dissolved in blood and extracellular fluids.) Explain why the carbon dioxide is moving out of the red blood cells into the alveoli (small air sacs in lungs) and why the oxygen is moving out of the alveoli into the red blood cells.

Blood returning to the lungs is high in CO2, but the fluid in the alveoli is low in CO2. The CO2 molecules are able to pass through the cell membrane with water, and since the concentration in the returning blood cells is so high the CO2 diffuses out of the red blood cells into the alveoli. The exact opposite is the case with the oxygen. The fluid in the alveoli is very high in oxygen, but the red blood cells that have just returned to the lungs is very low in oxygen. The oxygen diffuses from the alveoli into the red blood cells.

CELLULAR RESPIRATION

So, once the glucose has been created, how then do cells get the energy from the glucose so that they can use it? The release of chemical energy (from glucose) for use by cells. Through this process, oxygen enters a cell and reacts with the glucose to create a high energy substance known as ATP. Even plants need oxygen to break down the glucose and release the ATP.

Think of in the same way you might think of the engine of a car. Gasoline is a source of stored energy, but gasoline can do nothing on its own. It needs something to release the energy stored in it. In the case of gasoline, the agent that releases the energy is a spark. The spark ignites the gasoline and the energy within is released. In cellular respiration, the “spark” that releases the energy from glucose is oxygen.

As a result of cellular respiration, waste products are produced in the cell. One of the waste products is water. Another is carbon dioxide. And since energy was released, heat is produced and some of that is lost as waste. Carbon dioxide easily dissolves in water and is therefore eliminated from the cell with the waste water through osmosis.

Oxygen (O2)

1. Energy is stored in the glucose molecule similar to the way that energy is stored in propane gas.

2. Oxygen is like the flame that lights or ignites the glucose. Imagine lighting your grill with a lighter. This releases the energy in the propane. In this case the energy is in the form of heat.

Carbon dioxide wasteWater waste

Energy(ATP)

3. The oxygen reacts with (think “lights on fire” ) the glucose and releases the energy. The different molecules of the glucose are split apart and reassemble into carbon dioxide and water, two waste products.

oxygen

oxygen

CRASH!!!

Energy (ATP) Energy (ATP)

Water wasteCarbon dioxide waste

During cellular respiration

Oxygen is needed to

that is stored in

Release the Energy

Glucose Molecules

Photosynthesis vs. Cellular Respiration PhotosynthesisPhotosynthesis is a process wherein plants utilize sunlight to make food.It takes place inside the chloroplasts. Chloroplasts are located in the leaves of plants.Photosynthesis requires energy to produce glucose.It takes carbon dioxide, water and sunlight from the atmosphere to create glucose and releases oxygen back into the air.Photosynthesis occurs in plants and some bacteria. Formula:Carbon Dioxide + Water + Sunlight = Glucose + Oxygen6CO2 + 6H2O + Sunlight --> C6H12O6 + 6O2

Cellular RespirationCellular respiration is a process that converts food into energy which is used by plants and other living organisms.It takes place inside the mitochondria, organelles capable of breaking down glucose.Cellular respiration uses this glucose to create energy (ATP).It combines sugars with oxygen, releases the energy as ATP and carbon dioxide and water as by products.Cellular respiration occurs in all living organisms.Formula:Glucose + Oxygen = Carbon Dioxide + Water + EnergyC6H12O6 + 6O2 --> 6CO2 + 6H2O + Energy (36 ATP)

1. During aerobic cellular respiration, ____________________ is the catalyst that releases the energy stored in glucose molecules.

2. The energy released through cellular respiration is ________________

3. In addition to the ___________ released through cellular respiration, what other form of energy is released?

4. Which two molecules are released as waste from the process of cellular respiration?

5. What four “ingredients” are required for photosynthesis?

oxygen

ATP

ATPHeat

CO2 and H2O

Light, chlorophyll, CO2, and H2O

Check for Understanding B

6. The formula below illustrates the process of _______________________

7. The formula below illustrates the process of ___________________________photosynthesis

cellular respiration