unit 4: cool things cells do!

Early vegetarians returning from the kill When potato salad goes bad

UNIT 4: COOL THINGS CELLS DO!

Cell Processes and Energy • Guided Reading and Study

The Cell in Its Environment (pgs. 80-85 in book)

This section tells how things move into and out of cells.

Use Target Reading Skills

After you read the section, reread the paragraphs that contain definitions of Key Terms.

(We won’t collect this, but it is a good idea)-Use all the information you have learned to

write a definition of each Key Term in your own words. Write your definitions on a

separate sheet of paper. (Not an assignment, but good suggestion, rest of the page is an

assignment!)

Introduction (page 80)

1. The cell membrane is , which means that some

substances can pass through it while others cannot.

Diffusion (pgs. 81-82)

2. List three ways that substances can move into and out of a cell.

a. ________________________________

b. ________________________________

c. _Active Transport (pg. 84)___________

3. In diffusion, molecules move from an area of

________________________________ concentration to an area of _____________concentration.

4. Draw molecules on Part B of the diagram below to show how the molecules are distributed inside and outside the cell after diffusion has occurred.

Passive Transport

[H]

[L]

Passive Transport [H]

[L]

Active Transport

2


Osmosis (pgs. 82-83)

5. In ______________________ , water molecules diffuse through a selectively permeable membrane.

Active Transport (pgs. 84-86)

6. Two ways of moving things into and out of cells that do NOT need energy are ______________

and __________________.

Moving materials through a cell membrane without using energy is called

transport.

7. How does active transport differ from passive transport?

8. List two ways that the cell moves things by active transport.

a.

b. ________________________________________________________________

9. Is the following sentence true or false? As a cell gets larger, it takes longer for a molecule that has entered the cell to reach the middle of the cell.

10. Now explain #10 above!

3

Cell Membrane Surrounds cell

Separates the cell contents from the stuff outside the cell

-Lets some stuff pass through but not

others

Types of Movement Across the Cell Membrane

PASSIVE TRANSPORT -Movement of molecules that__________________ require _____ . For instance, it's easy for people to "spill" out of a crowded elevator.

. 1.

When many molecules crowded together they bump into each other over and over. The

bumps cause them to push away from each other

Molecules, by nature, easily spread out from a crowded area to a less crowded area until all the molecules are evenly spread.

_____________________-when the non-water molecules are evenly spread out

Oxygen can freely move across the cell membrane

Before Diffusion

Non-water molecules (dots) have

moved from an area of high conc.

to a low concentration so that the

% inside is equal to the % outside the

cell !

After Diffusion

(EQUILIBRIUM)-’cuz there’s an equal

concentration or % of molecules (dots)

both inside and outside the cell !)

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2. The DIFFUSION of -------------------- molecules from

an area of high water molecule concentration to an area of low

water molecule concentration.

-The movement of molecules that MUST use ________________________________

_____________________________because the molecules move from an area of __________

concentration to an area of concentration. For instance, it's

hard to pack people into an elevator that is already at its capacity.

---------------------- ----when the water molecules

are evenly spread out

3 . 1. Membrane surrounds a particle

2. Membrane wraps around particle and forms a vacuole 3. Cell takes the particle into the cell

Shrivels up like a raisin! Hey! That’s how raisins are made-OSMOSIS!

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4. Transport -Helps big molecules pass through the membrane

Why are cells small?

2. small size ='s less room to __________________stuff through the __ _ _

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AWESOME OSMOSIS & DIFFUSION

DEMONSTRATIONS

STATION 7 The Mysterious Vanilla Escape!

Background

15 drops of vanilla extract were placed inside a deflated balloon. No vanilla got on

the outside of the balloon. The balloon was inflated to a size that would fit into the

box, then the end was tied.

Procedure 1. Open the lid of the box just slightly. Take a whiff. What do you notice?

2. Why? The balloon appears to be solid….did you smell anything? Explain in the

space provided below (in terms of diffusion) why you think you smelled the vanilla molecules (think of the molecules as dots like previous discussions).

7

STATION 6 Limp Spuds!

Background Three pieces of potato were placed into a bowl of plain water. Three different

pieces of potato were placed into a second bowl containing a salt water mixture.

Procedure 1. Pick up a piece of potato from the plain water bowl. Next pick up a piece of

potato from the salt water mixture bowl. Describe any differences you notice.

2. What's going on? The potatoes in the plain water are taking in water since the

concentration of WATER molecules is higher outside of the potato ('cuz it's in

pure water, duh!) than on the inside. The potatoes in the salt-water mixture are

losing their internal water (yep, potatoes have water in them) because the

concentration on water molecules is higher inside the potato than outside of the

potato (where there's a lot of salt molecules in the water). What is the movement

of water molecules from an area of high concentration to an area of low

concentration called? _________________________________

POTATO SLICES (with skin

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STATION 5 Swollen Raisins!

Background The raisins in the water have been in the cup for at least 24 hours.

Procedure 1. Examine the raisins. Describe their appearance.

2. Since there were more water molecules outside of the raisin than inside of the raisin (raisins

are dehydrated grapes or grapes that have lost most of their water), the water moved from an

area of high concentration (outside of the raisin) to an area of low water molecule

concentration (inside the raisin). This process is called ________________________________

WATER

\

STATION 3 Exploding Vegetables!

Background These rhubarb or celery stalks have been placed in a bowl of water for at least 24 hours .

Procedure 1. Observe the stalks that have been soaking in water . Describe their

appearance. __________________________________________________________

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2. Rhubarb stalks are made up of long vertical bundles of cells that take in water at different

rates. Some of the bundles take in more water than other bundles causing the stalk to swell

and split apart at the weak points. When the water pressure in the cells reaches a certain

point, they burst open and curl because some of the cells have less water in them and have

not exploded. The cells with less water have not expanded as much and form the bottom

part of the curl. The movement of water from an area of high water molecule

concentration (outside of the rhubarb) to an area of low water molecule concentration

(inside the rhubarb) is called _______________________________________________

3. The main difference between diffusion and osmosis is that osmosis is the movement of

molecules from an area of high concentration to an area of low concentration where as diffusion is the movement of non- ____molecules from an area of high concentration to an area of low concentration.

WATER

RHUBARB

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Water moves out of the cells of a saltwater fish and into the ocean.

Cell Processes and Energy • Review and Reinforce

The Cell in Its Environment (Pgs. 80-85 in book)

Understanding Main Ideas

Fill in the blanks below (a, b, and c) with the word back above the picture to identify the

process illustrated in each of the following figures.

1 . _ .

Oxygen moves from the lungs into the bloodstream.

2 .

Answer the following questions in space provided

4. Explain how osmosis differs from diffusion.

5. Compare and contrast active and passive transport.

6. Identify two methods of active transport.

7. State one reason that cells are small.

Building Vocabulary If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true. 8. Selectively permeable means letting some but not all substances pass through.

9. Osmosis is the process by which molecules tend to move from an area of higher

concentration to an area of lower concentration. 10. The process by which water moves across a selectively permeable membrane is called

diffusion. 11. Diffusion and osmosis are types of active transport. 12. Passive transport requires the cell's own energy.

Sodium is pumped out of a nerve cell.

3.

WORD BANK for 1,2,3 below Diffusion Osmosis

Active Transport

11

___________

Cell Processes and Energy • Enrich

Facilitated Diffusion (Don’t need book)

The text describes two methods of passive transport: diffusion and osmosis. The diagram below shows another method of passive transport, called facilitated diffusion.

Why is facilitated diffusion needed? Some molecules are unable to pass through the cell membrane even though they are moving from an area of higher to an area of lower concentration. To pass through the cell membrane, these molecules must be facilitated, or helped, by a carrier molecule in the cell membrane. The carrier molecule attaches to a passenger molecule of the substance, carries it through a channel in the cell membrane, and then releases the molecule. The process can carry substances both into and out of cells, as shown in the diagram, and it requires no cellular energy.

Answer the following questions from the reading below each question 1. Why isn't cellular energy required for the passenger molecule to be carried across the cell membrane by

the carrier molecule?

2. Why do the passenger molecules need to be helped by the carrier molecule?

3. If the substance entering the cell was in higher concentration inside the cell than outside the

cell, what type of transport would be required? Explain your answer.

4. What is the difference between facilitated diffusion with the help of a carrier molecule and active transoort with the help of a transport protein?

cytoplasm

12

It’s really carried by the Golgi bodies or lysosomes, but the authors of the book forgot to consult US! ;)

13

____

Cell Membranes ·and Permeability

Safety

Review the safety guidelines in Appendix A of your textbook

Iodine is poisonous. Keep it away from your face, and wash your hands thoroughly after using it. Iodine will

stain your hands and clothing, so be careful not to spill it. Handle glass objects carefully. If they break, tell

the teacher. Do not pick up broken glass.

Procedure

Part A: Model of a Cell Membrane

1. Write your period # (BIG AND LEGIBLE) and everyone in your groups initials on a piece of masking tape

then stick it to a beaker so we can identify your period and who is in your group. In that beaker, there are

three test tubes that have been labeled as follows (1) “Iodine BEFORE” (2) “Iodine AFTER” and (3)

“Starch”

2. Fill the beaker with 40 mL of iodine solution. CAUTION: Be

careful with the iodine solution. If you spill any on yourself,

immediately rinse the area with water and tell you teacher. The

iodine solution represents the environment OUTSIDE the model cell.

3. Fill the test tube labeled “Iodine BEFORE” one-fourth full with iodine

solution, and then set it aside in a test tube rack.

4. Fill a plastic ziploc bag with 40 mL of starch solution, and seal the bag

**** Be careful not to spill starch onto the outside of the bag.

Record the color of the solution in Data Table 1, and then place the

Ziploc bag into the solution in the beaker. The bag represents a cell.

5. Fill the "Starch" test tube about one-half full with starch solution, record

the color of the solution, and then place the test tube in the beaker as

shown in Figure 1. Let the beaker and its contents stand overnight.

Iodine = brown liquid Starch = white liquid

Starch molecules

Iodine molecules

Figure 1

DAY 1

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Cell Membranes and Permeability (continued)

Observations

Data Table

6. The next day, remove the plastic bag and the test tube from the beaker. Record the colors of the solutions in the plastic bag and the test tube in the "Color AFTER" column in Data Table 1. ·

7. Pour iodine solution from the beaker into the test tube labeled "Iodine

AFTER" until the test tube has the same amount of solution as the test tube labeled "Iodine BEFORE."

8. Hold the two test tubes side by side, and look down through their openings. Record the colors of the solutions in the last line of Data Table

Analyze and Conclude

1. What part of the cell does the plastic bag represent?

2. What was the purpose of placing a test tube containing starch solution in the

beaker of iodine?

Solution Color Before Color After

Starch in model cell

Starch in test tube

Iodine in test tubes

DAY 1 DAY 2

time

HINT: why did the stuff in the bag turn dark brown, while the stuff in the test tube remained fairly clear?

Food for Thought: Molecules of iodine

move through the bag “membrane” turning

the starch purple. The starch molecules are

too big to move through the bag…now answer 2. below with

the hint given!

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3. When starch mixes with iodine the mixture turns purple/brown. What can you infer (or make

a best guess conclusion) about the contents of the plastic bag?

4. a. Did starch move out of the bag? Give a reason for your answer.

b. Did iodine move into the bag? Give a reason for your answer.

5. Based on your results, was the model cell membrane permeable (or let some stuff through) OR

Impermeable (doesn’t let anything through) to iodine? How about does the

model cell membrane let starch through?

6. In your model, how might the size of the membrane pores compare to the size of the starch molecules? Explain.

7. Cell membranes contain small holes, or pores. Pore size may determine why some chemicals can or cannot pass through a cell membrane. In your model, how might the size of the membrane pores compare to the size of the iodine molecules (are they smaller or larger)? Explain your answer.

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ACTIVE TRANSPORT - ENERGY TO TRANSPORT Active transport, simply put, happens when a cell

uses energy -to transport something.

We’re talking about the movement of individual molecules. The liquids inside and outside of cells are different. Sometimes a cell has to work a bit to maintain a proper balance of ions and molecules.

PROTEINS IN THE MEMBRANE

Active transport is usually done across the cell

membrane. Embedded in the lipid bilayer are proteins. It is those proteins that do much of the work of active transport. They are actually positioned to cross the membrane so one part is

on the inside of the cell and one side is on the

outside.

The proteins are very specific. One protein that moves glucose will not move calcium (Ca) ions. There are

hundreds of types.

There are other times when the proteins have to work against a concentration gradient. That process means they are pumping something (ions) from areas of lower to higher concentration.

While active transport requires energy and work, passive transport does not. These are several different types. It could be as simple as molecules moving freely (osmosis and diffusion) to processes that require proteins in the membrane 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 move

molecules more quickly.

PASSIVE TRANSPORT- TAKING THE EASY ROAD

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.

FACILITATED DIFFUSION Like a spaghetti strainer; only

some stuff gets through

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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 (diffusion of water)

Another big process 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.

Although concentrations like to be the same, the cell can pump

ions in and out to stay alive. Osmosis is the movement of water

across the membrane. Concentrations like to be the same. If

the cell is not going to pump out all of its 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 .

- .

HOW THINGS MOVE THROUGH THE

CELL MEMBRANE

1. When ENERGY is required to help stuff move through the cell membrane, it is

called __________________________-

2. Energy is required because things are being pumped from an area of ______________ concentration to

an area of _______________________ concentration. This would be like trying to stuff another

person onto an elevator that was already past its capacity.

3. When ENERGY is NOT required to help stuff move through the cell membrane, it is called

_________________________________________.

4. In this type of transport (see #3), things are moved from an area of _____________________

concentration to an area of _____________________concentration. This would be like

people exiting an elevator at full capacity to an empty lobby.

5. Explain how the cell membrane is like a spaghetti strainer.

6. The movement of water across the cell membrane is called ______________________________

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Autotroph An organism that makes _________________

An organism that can't make its own food

Photosynthesis The process plants (and a handful of photosynthetic animals) use to

Directly and/or indirectly, almost all living things get their energy

from _ __

___________+ ____________ + Sunlight _______________ + ____________________ (Sugar)

6 H2O + 6CO2 + Sunlight 6O2 + C6H12O6

Stages of Photosynthesis

Stage 1: Capturing _ _

Occurs in the in the leaves Chloroplasts are

___________________because they contain a photosynthetic green

pigment called _

Some of the stuff made in Stage 1 makes Stage 2 work

Stage 2: Using Energy to Make ______

Water comes in from rain (which is evaporated sweat and spit and tinkle and

other liquid stuff) through the roots

Carbon Dioxide comes in from our exhalations through the stomata

Stomata= little ___________on the undersides of leaves

Turns ______________ & _________________ into _______________ & _____________

Q: Why do plants make glucose?

A: To ________ themselves and store it as an ______________________ -

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Unit 4-Photosynthesis (Pages 86-90)

\

Introduction Just as you need flour and eggs to make cookies, a plant also needs raw materials to

make its own food. Plants use carbon dioxide gas and water as raw materials for a process called

photosynthesis. During photosynthesis, the chlorophyll in a plant's chloroplasts absorbs energy from

sunlight to power a series of chemical reactions. The end products of these reactions are sugars,

carbohydrates that the plant uses for food, and oxygen, a waste product. Click on the items in the ingredients box to add the raw materials for photosynthesis. When you are

finished, click the "Run Experiment" button to watch photosynthesis occur.

1. What "ingredients", are necessary for a plant to photosynthesize?

_____________+ ____________+ ______________

2. What products are given off as a result of photosynthesis?

_______________and _______________

3. What plant structure(s) takes in the water? ________________________

4. What plant structure(s) takes in carbon dioxide? ___________________________

5. What plant structure(s) gives off oxygen? ___________________________

6. Where, in the plant, can glucose be found? ______________________________

Chemical Reaction of Photosynthesis

The many chemical reactions of photosynthesis can be summarized by the equation below. Carbon

dioxide and water combine in the presence of light to produce sugar and oxygen. Drag and drop the items from the Ingredients Box onto the blank spots to build the equation for

photosynthesis. Write the EQUATION here:

22

OBSERVATION: LIGHTS OUT! Background Plants NEED sunlight in order to survive. Plants use sunlight to make food for themselves and consumers that eat them. If sunlight is not available, the plants use up their stored chlorophyll to make food. Chlorophyll is the pigment that makes leaves green. In the absence of sunlight, the existing pigment gets used up and is not replenished until sunlight once again becomes available. Because chlorophyll is necessary for plant survival, a plant without chlorophyll will either become dormant (as they do in the fall) and/or die.

Procedure 1. Observe the leaf that has been covered with dark paper for several days. What difference, if any,

do you notice between this leaf that has been covered and the

other leaves?

2. Based on the background, suggest what has likely happened to this leaf and why. 3. What might happen to the leaf if it were to remain covered for an additional week and why?

4. What might happen if all of the leaves were covered for an extended period of

time and why?

23


Photosynthesis (pages 86-90 in your book)

This section explains how plants make food by using the energy from sunlight.

Use Target Reading Skills

As you read, create a flowchart that shows the steps in photosynthesis. Put each step in a separate box in the flowchart in the order in which it occurs.

Sources of Energy (pg. 87 in your book)

1. In the process of photosynthesis, plants use the energy in ____________________ to make food.

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2. Complete the following table about how living things use the sun's energy.

The Two Stages of Photosynthesis (pgs. 88-90 in your book)

3. List the two stages in the process of photosynthesis.

a.

b. 4. The green pigment in chloroplasts, called ____________, absorbs light energy from the sun.

5. Is the following sentence true or false? Besides the energy in sunlight, the cell needs water and

carbon dioxide to make sugar. ___________________________

6. What are stomata?

How Living Things Use Energy From the Sun

Living Thing Autotroph or Heterotroph? Obtains Energy From the Sun

Directly or Indirectly?

Grass

Zebra

Lion

25

Cell Processes and Energy • Guided Reading and Study Photosynthesis (continued)

7. Circle the letter of each product of photosynthesis.

a. water b. carbon dioxide c. oxygen d. sugar

8. Is the following sentence true or false? Photosynthesis produces the carbon dioxide that most living things need to survive. -----------

The Photosynthesis Equation

9. Write the chemical equation for the process of photosynthesis.

10. What word does the arrow in the chemical equation stand for?

11. Circle the letter of each raw material of photosynthesis.

In other words, what, besides sunlight, does photosynthesis need in order to work?

a. carbon dioxide b. glucose c. water

d. oxygen

12. Circle the letter of each sentence that is true about the products of photosynthesis.

a. Plant cells use the sugar for food.

b. Some of the sugar is made into other compounds, such as cellulose. c. Some of the sugar is stored in the plant's cells for later use. d. Extra sugar molecules pass out of the plant through the stomata.

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Things made

Photosynthesis in plants and a few bacteria is responsible for feeding nearly all life of Earth. It does this by taking energy from the sun and converting it into a storable form, usually glucose (sugar), which plants use for their own life processes. Animals that consume plants also make use of this energy, as do those that consume those that consume plants, and so on to the top of the food chain. As important a job as making all of the world's food is, there's another vital function that photosynthesis performs: It generates the oxygen that oxygen-breathing animals need to survive. But here we animals repay the favor. We exhale the carbon dioxide that plants need for photosynthesis. Log on to: http://www.pbs.org/wgbh/nova/methuselah/photosynthesis.html

1. Click on the "Illuminating Photosynthesis" link (about 2/3 of the way down on the page) that requires Flash. If that doesn't work, try the non-Flash version

2. Click on "THE CYCLE" (You can reset the visual after you've begun if you need to; just

click on the reset button in the lower, right corner)

a. What does the PLANT need in order to start making oxygen (02)?

b. What does the girl give (directly and indirectly) to the plant? ______________________ and _____________________

c. What gas does the plant give to the girl? ___________________________

3. Click on "ATOMIC SHUFFLE"

a. All plants use the process of photosynthesis to make _

without it most life would desist (not exist).

b. Click NEXT. From where does the plant get its water? Some is made in the _ and some is absorbed by the _

c. Click NEXT. What happens to the water molecules? Where do the oxygen atoms go?

____________________________________________________________________

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http://www/

d. Click NEXT. The gas, ____________________________, enters the leaves through holes

called __________________________. From where does the carbon dioxide come?

___________________________________________

e. Click NEXT. What happens to the carbon dioxide? Into what does the plant convert it?

_____________________________________________________________________

f. Click NEXT. What does the plant build with the remaining carbons (C), hydrogens (H), and oxygens (0)? ____ _

g. Click NEXT. Fill in the blanks to show the equation for photosynthesis (but write in the simplified form by clicking on ''NOTE ABOUT THIS EQUATION"

6 ____ + 6 __ + sunlight + _ _ _ + 6 __

4. Click on "THREE PUZZLERS"

a. Puzzler 1: A tree inhales carbon dioxide; it needs to if it's to survive. But can it release

enough 02 to keep just one person alive?

YES or NO

b. How many people could an average-sized tree keep alive with its oxygen

production? _________________________________________

c. Click on the number 2 in the box in the lower, right-hand comer. A plant needs its own food to function. It can't make its own food at night. Beyond a few hours of darkness, can a plant stay alive without light?

YES or NO

(select the answer that is correct in MOST instances)

d. Click on the number 3 in the box in the lower, right-hand corner. A plant that receives the

nutrition it needs will continue to live, we now know. But what if we took all its 02 away? Do you think that the plant could still grow?

YES or NO e. Why is the answer correct?

5. ALL DONE! Log off and put your computer away!

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Cell Processes and Energy • Review and Reinforce

Photosynthesis (pgs. 86-90 in your book)

Understanding Main Ideas

Fill in the blanks in the photosynthesis equation below with the names of the missing compounds. Then answer the questions that follow in the spaces provided.

sunlight

1. __________________ + 2. __________________ 3. _________________+ 4 ._____________

5. What are the raw materials of photosynthesis?

6. What are the products of photosynthesis?

7. Why is sunlight written above the arrow in the equation, rather than on either side of it?

8. Where does photosynthesis occur?

Building Vocabulary

Fill in the blank to complete each statement.

9. The process by which a cell captures the energy in sunlight and uses it to make food is called _

10. _______________________________________are colored chemical compounds that absorb light.

11. The main pigment found in the chloroplasts of plants is

12. _________________________________are small openings on the undersides of leaves through which carbon dioxide enters a plant.

13. An organism that makes its own food is a(n) _

14. A(n) ___________________________is an organism that cannot make its own food.

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Notes-Respiration (pgs. 91-94 in book)

Respiration The process cells use to ___________________ (glucose)

How does the food get to the cells?

Mouth Stomach Intestines Blood Stream Cells

Once the "food" gets to the cell it enters through the cell membrane and

goes to the Mighty ! Sometimes called Cellular Respiration so it's not confused with breathing (which is a process that brings in the oxygen that's needed for Cellular Respiration)

,Two Phases of Respiration

Phase 1

Phase 2

Takes place in the ____________________

Breaks down the glucose into smaller molecules Makes molecules of energy

Takes place in the ___________________

Breaks down the small glucose even more Requires _____________________________ Makes __________molecules of energy

AND

_ (which ends up back in our lungs to breathe out and give to plants)

AND

_ (which we lose as sweat and oil and tinkle and spit and tears and more which ends up watering plants)

30

cytoplasm

Cellular Respiration Equation (photosynthesis equation backwards)

______________ + ________________ _________________+ _ ________ + Energy (32 units) C6H12O6 + 6 O2 6 CO2 + 6 H2O + Energy (32 Units)

Fermentation A process that makes energy for cells without using _ _

Doesn't make nearly as much energy as cellular respiration

Alcoholic Fermentation

Type of fermentation used by yeast (and a couple other organisms) to break down sugars

Produces ___ _ (instead of water) &

Lactic Acid Fermentation

Takes place in your body when your cells are using up oxygen fast than it can be replaced

Produces ___ _ (instead of water) & _ __

Lactic acid build-up makes your _______________________ feel sore

31


Respiration (pgs. 91-94) In this section, you will learn how cells get energy from food. Use Target Reading Skills Before you read, write a definition of respiration in the graphic organizer. As you read, revise your definition based on what you learn.

What You Know 1. Definition of respiration:

What You Learned

What Is Respiration? (Pgs. 91-93 in your book)

1. What happens during respiration?

2. Cells store energy in the form of ______________________________.

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Respiration (continued)

3. How do cells "withdraw" energy?

4. Is the following sentence true or false? Respiration that takes place inside of cells is the same as breathing air in and out of the lungs.

5. Use the table below to list the raw materials and products of respiration.

Match the events in respiration with the stages in which they occur. The items in the second column may be used more than once.

Event in Respiration

6. Takes place in the mitochondria

7. Takes place in the cytoplasm

8. Oxygen is involved.

9. Energy is released.

10. Glucose molecules are broken down.

Stage of Process

a. first stage

b. second stage

c. both first and second stages

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Respiration

Raw Materials Products

XXXXXXXXXXXXXXXXXXX


11. Complete the cycle diagram below, which describes the relationship between

photosynthesis and respiration.

Photosynthesis Respiration

Fermentation (pages 93-94)

12. What is fermentation?

13. Is the following sentence true or false? Fermentation releases more energy than respiration. _ _

14. List the two types of fermentation and tell where each takes place.

a.________________________________________________________________

b. _____________________________________________________________

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Making and Carbonating Pop through Fermentation in Respiration

Background Fermentation has been used by mankind for thousands of years for raising bread, fermenting wine and brewing beer. The products of fermentation of sugar by baker's yeast, Saccharomyces cerevisiae (which you can buy at any grocery store), are ethyl alcohol (if you let your potion brew long enough) and/or carbon dioxide. Carbon dioxide causes bread to rise and gives carbonated drinks their bubbles. In this lab, you will ferment sugar with baker's yeast, then capture the generated carbon dioxide to carbonate your very own soda pop! Necessary Equipment Clean - Funnel

plastic drink bottle with cap sugar pop extract yeast cold, un-chlorinated water

Measuring Cup 1/4 tsp measuring spoon 1 tbl measuring spoon

Procedure 1. With a dry funnel, add (in this order) one (1) level cup of table sugar, then ¼ teaspoon of

powdered yeast.

+

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2. Put the lid on your bottle, then shake to evenly distribute the yeast grains into the sugar.

3. Swirl the sugar/yeast mixture in the bottom to make it concave (to catch the extract)

4 Have your teacher add 1 mL of flavoring/extract on top of the dry sugar. The extract will stick to the sugar which will help dissolve the extract in the next steps.

5. Using a funnel, fill your bottle HALF WAY with fresh, cool tap water (the less chlorine the better). Rinse off in the extract which sticks to the tablespoon and funnel. Swirl the bottle contents to dissolve the ingredients (about a minute).

6. Fill up the rest of the bottle so that about an inch or more of air space remains. Securely screw on the cap to seal. Invert the bottle repeatedly (for a minute or more) to thoroughly dissolve the ingredients.

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7. Label your bottle by writing your period number and group number (ie. P1, Grp #1) on a piece

of masking tape and sticking it to your pop bottle. Push the bottle back against the wall.

8. Allow your bottle to remain at room temperature (so that the live yeast can begin eating/fermenting

the sugar and reproducing so that it can eat/ferment more sugar) for about 3-4 days or until the

bottle feels hard to a forceful squeeze. DO NOT leave the bottle at a warm temperature for more

than two weeks or you will risk explosion!

9. When ready, refrigerate your pop overnight or longer, then serve (refrigerated pop does not pose an

explosion risk).

10. Slowly twist the lid of the chilled pop to slowly release the pressure.

11. There will be a sediment of yeast at the bottom of the bottle, so that last bit of the pop will

probably be pretty gross.

12. Distribute amongst your group and enjoy!

13. And now for the pressing question: Can I get drunk from this concoction? In short, NO. Testing has shown that the alcoholic content resulting from this fermentation process can be up to 0.35% (if left for near or over two weeks before refrigerating). Comparing this to the 6% in many beers, it would require a person to drink about 2 GALLONS of this pop to be equivalent to one 12 ounce beer. Most people would call this amount of alcohol negligible, but for persons with metabolic problems who cannot metabolize alcohol properly or with religious prohibition against any alcohol, consumption should be limited or avoided. Despite the fact that one or two students always suggest that their pop tastes like beer (of course, we teachers must ask, "how do you know?"), this experiment produces little IF ANY alcohol because we do not allow it to ferment long enough (usually only 2-4 days). Any resemblance to an alcoholic taste is the result of the yeast used to ferment the sugar.

14. Clean up!

a) Rinse out/off all equipment thoroughly (except for the cup of sugar.) b) Wipe off counter, sink, and lab table area c) Place equipment together neatly.

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Several days later…

Cell Processes and Energy • Enrich

History of Fermentation

People have known about and used fermentation for thousands of years. But it has been only in

the past two hundred years that scientists have come to understand this important process. In 1854,

the French chemist Louis Pasteur determined that fermentation is caused by yeast. His work was

influenced by the earlier work of Theodor Schwarm, the German scientist who helped develop the cell

theory. Around 1840, Schwarm concluded that fermentation is the result of processes that occur in

living things. In 1907, a German chemist named Eduard Buchner received the Nobel prize for showing

that enzymes in yeast cells cause fermentation. About two decades later, two other scientists

determined exactly how enzymes cause fermentation. Their names are Arthur Harden and Hans Euler-

Chelpin, and they won the Nobel prize for their work in 1929. By the 1940s, technology was developed

to use fermentation to produce antibiotics.

Why is understanding fermentation so important that it has led to the awarding of Nobel prizes?

Fermentation is a very useful process. Today it is used to produce industrial chemicals, medicines such

as antibiotics, and alcoholic beverages, as well as to make bread rise and to preserve many types of

food. Some of these uses have been known for thousands of years. For example, the Chinese used

fermented soybean curd to treat skin infections 3,000 years ago, and they started using fermented tea

to treat a variety of illnesses as early as 220 B.C. The use of fermentation to make bread rise and to

produce alcoholic beverages is as old as the development of agriculture itself, which most scholars

date to about 8000 B.C.

Answer the following questions under the question below.

1. Use the information provided in the passage above to make a timeline of the history of fermentation.

2. What contribution did Louis Pasteur make to the understanding of the process of fermentation?

3. What are two of the oldest uses of fermentation?

4. How is fermentation used in medicine today?

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unit 4: cool things cells do!

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