The Cell

The Cell

What is a What is a Cell?Cell?Living cells:– are made up of just a few important chemical elements (carbon, hydrogen, oxygen, nitrogen,

phosphorus and sulfur)– are the basic unit of structure and function of all living things– come from other cells after life began, and– are different from viruses

True or False?

1. Organelles are collections of cells. T / F 2. Cells give our bodies structure. T / F 3. Living cells can only come from other living cells. T / F 4. Viruses are one example of living things. T / F 5. Our bodies contain a complicated mix of all of the chemical elements. T / F 6. Complex organisms are formed by groups of cells. T / F

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What is a Cell?

About Living CellsHave you ever been asked to sweep or vacuum around

your house? If not, have you ever noticed the dust that collects all around a room? Believe it or not, most of this dust comes from you and the other people you live with – as dead skin cells!

Your body is constantly producing more and more cells as other cells die. In fact, our bodies are only made up of cells and some fluids that are trapped between them. This means that cells make more cells – but really, what are they?

A cell is actually very complex. Some scientists spend their entire lives studying just one little part of how just one type of cell works. However, understanding what a cell is and what it does is actually quite simple. Each cell is basically a bag of water, DNA, protein and some things called organelles. The organelles inside of a cell are responsible for making energy, getting rid of waste and making proteins, among other things.

A living thing is made up of a collection of one or more cells. However, one lone cell cannot accomplish very much – take a swim, eat some lunch, find a mate – but a group of cells can get together and form a much more complicated organism. Sure, that group of cells can take swims, find mates and even eat dinner, but it can do more than one thing at one time. A plant, which is a group of cells, can capture the energy of the sun, pick up water with its roots, turn carbon dioxide into sugar and oxygen and open up its flowers all at the same time! And if you as a human are really talented, you can text message, listen to your teacher, and make googly eyes at your boy/girlfriend across the room all at the same time. Just think, if you were a single-celled amoeba, you wouldn't even have a pocket for your cell phone. How wonderful it is to have more than one cell!

Cells make up things like our bones, skin, heart, liver and brain. Since our bones form the structure for the rest of our body, we say that cells are the most basic unit of structure. This is true for all living things, whether or not they have bones. For example, a jellyfish has no bones, but cells make up their arms and body. Also, a jellyfish is able to swim and sting their prey because they have special cells that perform certain functions. As humans, we have special cells that beat around 80 times every minute called heart (cardiac) cells. We also have cells that carry oxygen around our bodies called red blood cells. For this reason, we say that cells are also the basic unit of function in all living things.

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A virus

A single cell

A bacterium

The Cell

You know that if your teacher catches you texting on your cell phone, that you might get a call home to your grandmother, grandfather, mom or dad. Why are those people most closely related to you, anyway? Because your cells came from their cells! All living cells come from other living cells. A famous experiment was once done on rotting meat. At the time, people believed that flies came from rotting meat – not other flies. So a scientist took two containers of rotting meat; over the first container, he put a screen that prevented flies from landing on it. He left the second container uncovered. Sure enough, flies started to land on top of the second container, and before long, the rotting meat was covered with maggots (fly babies). However, the flies never got on the meat in the first container, no maggots appeared, and no flies appeared inside the container. Flies could only come from other flies!

Since then, scientists have discovered much about cells and also about things that are not considered living cells, such as viruses. Viruses, which lack a nucleus, can infect living cells by using the cell to make more viruses, but without a living cell, a virus cannot make more copies of

itself. The virus itself never gets any bigger or smaller, and doesn't take any gases or other materials from its environment. Different viruses can survive in different environments, such as HIV which needs to be in body fluids like blood or semen, but no virus can make more copies of itself, by itself. This is why most scientists do not consider viruses to be alive, even though they have organic molecules like proteins.

At this point, you may be asking yourself, what are living cells actually made up of? Truthfully, you're probably not asking yourself this question, but it would be a good question to ask. All of those organelles in the cell (like the cell membrane, DNA, ribosomes, etc.) are made up of different combinations of just a few chemical elements. It's thought that these chemical elements were around when the Earth first cooled down 4 billion years ago: carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur. Believe it or not, almost your entire body is made up of combinations of these elements, elements that originally came from our sun!

True or False?

1. Organelles are collections of cells. T / F 2. Cells give our bodies structure. T / F 3. Living cells can only come from other living cells. T / F 4. Viruses are one example of living things. T / F 5. Our bodies contain a complicated mix of all of the chemical elements. T / F 6. Complex organisms are formed by groups of cells. T / F

2009 – 2010 4

Types of diatoms, which are single-celled protists

A look at the cells connecting your brain to your muscles

What is a Cell?

QuestionsQuestions

Do you remember? 1. State how new cells come about. 2. Identify the role of a cell to an organism. 3. Since the Earth came from the sun, and the sun is mainly made up of hydrogen, where did

the other chemical elements in all cells come from?

Think about it! 4. Differentiate (tell the difference between) a cell and a virus in two ways. 5. Paraphrase (summarize briefly in your own words) the experiment done to prove that cells

come from other living cells.

Do something! 6. Argue for the case that a virus is actually a living thing. Use the Sandwich Chart on p.Error:

Reference source not found to structure your argument!

Remember? 7. What do animals breathe in? What do animals breathe out? 8. Explain why there is a difference in skin tone between Europeans and Africans. 9. Which classification is the most general? The most specific? 10.What is a fossil?

ActivitiesActivities

Preparing SlidesPreparing Slides

You will prepare three slides of your own choosing from substances that you bring in or that are in the classroom. For each slide, do the following:

1. Clean a slide and slide cover 2. Place the subject (what you’re looking at) on the slide, then place the slide cover on top

of the subject 3. Describe what you think you will see before you look at it in the scope 4. At each magnification (4x, 10x, 40x), describe what it is that you see in a few words 5. Sketch a picture of what you see, as best you can 6. Wash and dry the slide and slide cover

VirusViruseses

1. In your own opinion, are viruses alive? Why or why not? 2. Talk to three other people who may or may not know about viruses. Explain what a virus

is to them and: a) Write down their opinion about whether it’s alive or not b) Compare this opinion to your own c) Write down their name

3. Has talking to other people changed your opinions at all? Why or why not? 4. A virus reproduces by using a host cell to clone its DNA (or RNA) for it. Draw or sketch a

three-frame comic strip which illustrates how this happens. 5. Complete a Venn diagram of two similarities and differences for viruses vs. bacteria.

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The Cell

Using a MicroscopeUsing a Microscope

Label the microscope below and list the steps to follow when using a microscope to look at a prepared or temporary slide:

2009 – 2010 6

What is a Cell?

What is a What is a VirusVirus??

1. What is a virus? Complete the table, using the text:Function / Structure Present in virus?

RespirationGrowth

ReproductionDNA/RNANucleusProteins

2. With the Play-Doh, create and name your own virus. Sketch, label and explain what your virus infects!

3. Do you think a virus is a living thing? Explain!

How How VirusViruses Spreades Spread

By Randall Good

This activity will show you how viruses can spread through a population. You will receive one test tube and one pipette, which may or may not contain a mildly toxic acid, so be careful with it!

1. Move around the room for five minutes and exchange fluids with at least three other people.

2. Return the pipettes to the front of the room and then go back to your seat without spilling your test tube.

3. Put a pipette full of pH indicator in your test tube.

One of the test tubes had originally been infected with the acid; it is now our task to figure out who was the source of the “virus”! This person will be called patient zero.

4. Write down all of the students that you exchanged fluids with.5. Put a star next to each student's name who tested positive for the virus.6. Could you have been patient zero? Why or why not?

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The Cell

What is Inside of a Cell?What is Inside of a Cell?Compare the structure, function and the relationships of cell organelles in eukaryotic cells and prokaryotic cells. For example, nucleus, chromosome, mitochondria, cell membrane, cell wall, chloroplast, cilia, flagella.

True or False?

1. Chromosomes are organized into one or more DNA. T / F 2. The cell membrane decides which nutrients come into and out of the cell. T / F 3. The mitochondria gives shape and structure to the cell. T / F 4. Flagella are responsible for the movement of some cells. T / F 5. Photosynthesis happens inside of chloroplasts. T / F 6. Mitochondria produce nutrients for the cell. T / F

About Organelles

Cell Type Prokaryotes Eukaryotes

Kingdom Monera (Bacteria)

Protists Plants Fungi Animals

Nucleus? No Yes Yes Yes Yes

Mitochondria? No Yes Yes Yes YesMulticellular? No No Sometimes Sometimes Yes

Chloroplasts? No No Yes Sometimes NoCell Wall? Yes Yes Yes Yes No

As we've seen before, there are two major types of cells, prokaryotes and eukaryotes. The main difference, remember, is that prokaryotes have no true nucleus while eukaryotes have a nucleus (and can be multicellular). Prokaryotes came before eukaryotes, by about 3 billion years. While there are many theories as to how this happened, scientists are certain that the prokaryote is the older organism.

There are two types of prokaryotes, bacteria and a type of organism called “archaea”. We will only be focused on bacteria, as they are more well-known (even though archaea can be found in every corner of the world, too). Bacteria, even though they are very simple, still have DNA

organized into one or more chromosomes. Bacteria have ribosomes and are surrounded by both a cell (plasma) membrane and then a cell wall. The cell membrane decides which nutrients and other materials can come into and out of the cell. It's very important that nutrients the cell needs are allowed inside and that waste is allowed to leave!

The reason that water and certain other materials move across the cell membrane without the help of the cell membrane is because of osmosis. Osmosis is when water molecules move from a higher to a lower concentration. In the picture of osmosis, the smaller molecules are water, which pass from the left to the right-hand side until they are equal because they are in a lower concentration on the right-hand side. Osmosis is a type of diffusion. Diffusion is where molecules spread out until they are evenly distributed in a medium, such as the air.

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Osmosis: The smaller molecules are water and the middle is a cell

membrane

What is Inside of a Cell?

The cell wall gives shape and structure to the cell. Inside all living cells, including bacteria, there is one or more chromosomes. These chromosomes contain all of the genetic information needed for the cell to stay alive and carry out all of the things that a cell does. Sometimes, cells like bacteria also have things called cilia or flagella. These are like tails for the cell and help it move around in liquids. Human sperm cells have flagella so that they can move toward the egg.

Since plants use the energy from the sun, they need to have specific organelles to capture that energy. The organelles that do this are called chloroplasts. The chloroplasts are green themselves because of chlorophyll, which captures sunlight. It is inside the chloroplasts that photosynthesis happens where carbon dioxide and water gets turned into sugar and oxygen.

As you can see in the chart at the beginning of this chapter, there are many differences between prokaryotes and eukaryotes. As eukaryotes came into being about 3 billion years after prokaryotes, they are more complicated. Eukaryotes have a nucleus which contains the DNA (that is made up of chromosomes). Also, they have mitochondria which are responsible for producing the energy that the cell needs. The nucleus, chloroplasts and mitochondria have membranes surrounding them (like the cell membrane) that decide which materials can enter and leave the organelle.

True or False?

1. Chromosomes are organized into one or more DNA. T / F 2. The cell membrane decides which nutrients come into and out of the cell. T / F 3. The mitochondria gives shape and structure to the cell. T / F 4. Flagella are responsible for the movement of some cells. T / F 5. Photosynthesis happens inside of chloroplasts. T / F 6. Mitochondria produce nutrients for the cell. T / F

QuestionsQuestions

Do you remember? 1. Which kingdom of living things does not have a cell wall? 2. How is DNA organized? 3. What is the role of chloroplasts?

Think about it! 4. Differentiate prokaryotes and eukaryotes in three ways (from this chapter). 5. Predict the consequences of eukaryotes not having a nucleus to hold their DNA.

Do something! 6. Draw a sample plant cell.

Remember? 7. Why doesn't it matter what scientists think about natural selection? 8. What are the five kingdoms of living things? 9. Is there just one rock sequence? Why or why not? 10.State how new cells come about.

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Archaea, a type of prokaryote

The Cell

The Ultimate Basketball PlayerThe Ultimate Basketball PlayerBy Devin M.

A guy named LeKobe Paul wanted to know more about what happens every day inside of his body. He went to a science lab to ask professionals. There, he met Dwayne Garnett, a Cells Specialist. Garnett had a PhD in the study of cells, so he could tell LeKobe anything about cells.

LeKobe began asking a series of questions and Garnett stopped him. Garnett could see that LeKobe was very anxious to learn more about cells. So Garnett said he would go over a couple organelles in the cell of an animal and a plant. Garnett began by saying that all animal cells have a cell membrane and that it was the security guard of the cell; only certain substances could pass. Next, he said that all cells have DNA and it works like a computer because it contains all of the information for the cell's genetic code. Garnett then said cells have ribosomes which are inventors because they create proteins. LeKobe was eager to learn more because he had never known all of this happens inside of him. Garnett continued to share his knowledge by saying that some prokaryotic cells have flagella and that this is like the car because it helps the cell move. Garnett also said a plant cell has a cell wall which works as the frame of the plant cell. Inside of that cell wall you'll find cytoplasm which works like junk because it just takes up space.

LeKobe was fascinated by the cells in his body but now he wanted to know more about plant cells. So Garnett told him that since plants use energy from the sun, they need chloroplasts. Chloroplasts are fishnets of the cell: they capture sunlight. Garnett ended his long lecture by giving one more fact, this one about eukaryotes. He said eukaryotic cells have mitochondria which work like an engine and provide all of the energy the cell needs.

LeKobe was grateful and he shook Garnett's hand, then waved goodbye. On the way home, some scrubs challenged LeKobe to a basketball game. LeKobe dropped 150 points in 10 minutes and only allowed 2 points because he was distracted by a beautiful young lady walking down the street.

Interview with a Interview with a RibosomeRibosomeBy Cyen TissShaw High School

Recently, I had the pleasure of being shrunk down to microscopic size and traveling through a human skin cell. I was able to talk to many of the organelles, but by far my most interesting conversation was with Robert, a ribosome. The following is what we talked about.

CT: Thank you for taking the time out of your busy schedule to talk to us!

R: No problem – I’m just going to finish up making this protein, and I’ll get with you.

CT: Okay.

[There is a two-minute delay while Robert releases the DNA he has a hold onto and lets go of the protein he just made.]

R: Now. What did you want to talk about?

CT: Well, I hardly know where to begin. Why don’t you tell me about where you grew up, what your childhood was like, you know, how things started?

2009 – 2010 10

Robert, left, and two other ribosomes on a strand of DNA

What is Inside of a Cell?

R: Cyen, that was a few hours ago now, but let’s see what I can tell you. I was born over in the nucleolus, you know, that small ball in the middle of the nucleus. I spent the first minutes of my life in the nucleus, hanging out with DNA. It was there that I met older ribosomes and they showed me how to make proteins.

CT: Really! Now, what’s that like?

R: Making proteins? It’s quite fun. You see how I have two halves, a small and a large half? Well, what they showed me is how to get a hold of the strings of DNA like this [Robert grabs a long, thin string of DNA between both halves, see picture above] and peel the two strands apart. Then, I read one of the strands and build a protein.

CT: How do you make the protein?

R: The process is pretty complicated, but all you really need to know is that the DNA has all of the instructions that I need. The older ribosomes all showed me how to make proteins really well.

CT: Now, I see proteins floating around all over the place in this cell. Where do they end up going?

R: The proteins? Oh, that’s easy. These proteins are made by me and my ribosome friends in the nucleus, you see, and then

they leave the nucleus for the rest of the cell. There’s a story told by all the ribosomes that the proteins just used to leave the cell membrane and that was it, until Golgi came along.

CT: Gol … what?

R: Oh, Golgi. Like you’re saying “bulgy.”

CT: Golgi!

R: Now you’ve got it. Right. So these Golgi apparatus came along and they decided that they would come up with a solution. The Golgi hang out in the cytoplasm of the cell and package up all of these proteins so that they can make their way outside of the cell. There’s a Golgi apparatus right over there [Robert points with his small half to a green object that looks like a stack of pancakes]. The proteins start out at that smallest layer and then work their way through all of the layers. By the time they’ve gotten to the last layer, they’re all wrapped up and ready to go.

CT: Tight.

R: Yeah, I think it’s pretty cool.

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Stereoscopic image of a protein: to see it in 3 dimensions, cross your eyes to merge the two

images into one

Golgi apparatus

The Cell

CT: But what happens when you make too many? I see a huge pile-up at this Golgi apparatus right over here?

R: Oh, well, what happens is that those extra proteins go over to one of those weird-looking vacuoles [see picture to the left]. They’re in charge of storage. In fact, I made a protein this morning that went straight to the vacuole – all because this one Golgi apparatus got stressed out and couldn’t handle his load of proteins. I hope they make it through the day or the whole cell will

die.

CT: Wow! It’s that serious?

R: For real. All the ribosomes over there are talking about it [Robert points to a group of ribosomes hanging out on a strange, folded object].

CT: What’s that hang-out spot called?

R: That’s the endoplasmic reticulum. I don’t really know why we call it that, but everyone just says “E.R.” for short. And when we’re hanging out on it, it’s called “rough E.R.” When there’s no ribosomes there, we call it “smooth E.R.” because you never run into any trouble.

CT: What happens on the E.R.?

R: Well, that’s what we like to call the kitchen. All the chemicals in the cell get processed there, so everything gets cooked up nice and neat. In fact, I just had lunch on that E.R. right next to you. Cooks up a nice carbohydrate that one, let me tell you. Speaking of, it’s dinner time and then I have to go make some more proteins.

CT: OK, I’ll let you go! Thanks a lot for talking to us!

R: My pleasure.

Respond 1. Name the eight organelles mentioned in this interview. For each one, write down its name

and function in your own words. 2. In detail, how is a protein made? 3. In your own words, explain what happens to a protein after it is made until it leaves the cell. 4. What are two questions you would ask a ribosome (or any other organelle in the cell)?

ActivitiesActivities

2009 – 2010 12

What is Inside of a Cell?

CellCells Under the Microscopes Under the Microscope

On a separate sheet of paper, describe the different cells that you can see in the microscope. What are three things that all cells have in common? What are at least two differences between plant and animal cells?

Define: 1. Metabolism 2. Cell Membrane 3. Cell Wall 4. Photosynthesis 5. Nucleus 6. Mitochondria

Kingdoms of LifeKingdoms of Life

In this activity, you will do research to complete the following chart:

Name Kingdom Multi- or single-celled? Does photosynthesis? Has a centriole?

Bed bug

House fly

Yeast

Yogurt

E. coli

Corn

Moss

Beans

Mushroom

Fern

Cheese

Amoeba

The Jelly Bean ProblemThe Jelly Bean Problem

By Glenn Westover

How can large particles of food and other nutrients get into cells? The cell is full of cytoplasm, a fluid, and the cell membrane has to remain intact. It is like a water balloon; the cell membrane cannot break, because if it does, the entire cell will burst.

1. How do large particles, those too large to diffuse, get into cells? 2. Do cells have mouths? 3. Does swallowed food mingle or mix with the organelles? 4. Which cell organelle could function as a mouth? 5. Get the following materials (per group): 1 plastic shopping bag, 1 pair of scissors, 15 cm

of string, 4 pieces of wrapped candy.

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The Cell

The Jelly Bean ProblemThe Jelly Bean Problem

With the materials in hand, you must get the candy into your bag according to the following rules:

a) The candy must enter through a solid part of the bag. b) The inside of the bag may not be directly open to the external environment. c) The candies entering the bag must remain clustered together. d) Students may work with their hands in the bag to act as the inside of a cell. e) The candy may be eaten only if it enters the bag "cell" under the specified conditions.

6. What you just accomplished is called endocytosis. Make a drawing of endocytosis.

Functions of the Functions of the CellCell Wall Wall

The cell wall is responsible for maintain the shape and structure of the cell. Bacteria often have a chemical called peptidoglycan in their cell wall. The cell wall also is responsible for maintaining the correct balance of water in the cell.

1. What do you think would happen if there were a large hole in the cell wall? 2. Peptidoglycan is produced by the ribosomes inside the cell. When this protein reaches

the cell wall, what does the cell wall do? 3. Suppose that a bacteria in a pond is very dehydrated. What will the cell wall do, and

why?

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What is Inside of a Cell?

Functions of the Functions of the CellCell Membrane Membrane

The cell membrane (or plasma membrane) is referred to as being “selectively permeable,” meaning that it allows some substances to pass through while it prevents other substances from leaving. State whether the cell membrane allows the following materials to pass through and why or why not:

1. Waste is produced by the ribosomes inside the cell. 2. The cell wall allows sugar (which contains energy) to reach the cell membrane. 3. The DNA hits the cell membrane.

Functions of Functions of RibosomeRibosomess

The ribosomes are small organelles that float around the inside of the cell, looking for DNA. They are made up of two parts, a small and a large part. When they trap the DNA between the two parts, they read the DNA’s code and create proteins. These proteins go on to make up everything in the prokaryotic cell.

1. Let’s say that there’s a disease which only affects the ribosomes in a prokaryotic cell. What do you think will happen to this cell?

2. Why is it important that the ribosomes and DNA are both in the same part of the cell? 3. Can ribosomes leave the cell membrane? Why or why not?

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The Cell

Functions of Functions of DNADNA

The DNA (or deoxyribonucleic acid) contains all of the genetic information for the cell. 1. The DNA contains two copies of the cell’s genetic information. When a bacterial cell splits

into two cells, what do you think will happen with the DNA? 2. A new bacterial cell will produce a copy of its own DNA. What is it called when there is an

error in the copy? [Hint: You may need to use the biology book for this!] 3. The genetic information that is contained by DNA will help to create proteins. What

organelle needs to join the DNA in order to create proteins?

Functions of Functions of FlagellaFlagella

The flagella is a tail-like structure that some prokaryotic cells have in order to help them move. 1. Most, but not all bacteria have flagella. In what environment is there bacteria that need

to have a flagella? Why? 2. Think about what we’ve learned about natural selection. What advantage does having a

flagella give over bacteria that do not have it? 3. Again, think about what we’ve learned about natural selection. Why do some bacteria

not have a flagella? In other words, what advantage does it give to a bacteria to not have a flagella?

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What is Inside of a Cell?

Functions of Functions of CytoplasmCytoplasm

The cytoplasm is the jelly-like substance that takes up space on the inside of the cell. It is mainly composed of salty water and proteins. Organelles move easily through the cytoplasm, and it pushes on the cell membrane like water in a water balloon.

1. Why, do you think, is the cytoplasm mainly made up of salty water? [Hint: Think of what else is made up of salty water and where the first cells evolved.]

2. Why is it important that the organelles move easily through the cytoplasm? 3. What would happen if the cytoplasm did not push on the cell membrane at all?

Prokaryotic Prokaryotic CellCellss

Use play-doh so that you can make a model of the prokaryotic cell. You will need the following information:

Organelle Function ShapeCell Wall Structure & strength Almost rectangular and defines

the size of the cellCell Membrane

Decides what comes in & out of cell Fits on inside of cell wall

DNA Contains all information necessary for life Coiled stringRibosomes Makes proteins (the building blocks of

life)Small and round

Flagella Movement Tail-like, can be as long as the cell

1. Make a model of the cell with the play-doh 2. Sketch and label the cell, putting the functions of each organelle on the sketch 3. In your own words, what does “prokaryote” mean?

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The Cell

Eukaryotic Eukaryotic CellCellss

1. What is the major difference between prokaryotes and eukaryotes (do not give book definitions)?

2. Use the timeline in the front of the room and your notes to answer the following: a) Since the monera kingdom was the first kingdom of life to come about, how many

billion years ago did the monera kingdom begin? b) When did protists evolve from monera? c) When did animals, plants and fungi evolve from protists?

3. Using the Play-Doh, create, sketch and label a eukaryote, keeping in mind that a eukaryote has all of the organelles as a prokaryote (cell wall, cell membrane, DNA, ribosomes) plus all of the following:

Organelle Function ShapeNucleus Controls cell, contains DNA Large ball in the middle of the

cellNucleolus Makes ribosomes Small ball in the nucleusEndoplasmic reticulum Site of chemical reactions,

attachment of ribosomesFolded paper outside nucleus

Golgi apparatus Packages proteins Stack of pancakes outside nucleus

Vacuoles Storage Various shapes outside nucleus

Cell MetaphorCell Metaphor

The purpose of this activity is to create a metaphor for the major organelles of the eukaryotic cell. A metaphor is a useful way to remember the functions of the cell. For example, if my metaphor was that a cell can be like a school:

Cell organelle Metaphor: School

Nucleus The main office, because it directs the actions of the school

Cell Wall The outer walls of the school, because they keep out cold, heat

Cell Membrane The security guards, because they choose who to let through

DNA The teachers and books, because they have the information

Ribosomes The students, because they make the school function

E.R. The cafeteria, because it's where the students are fed

1. Choose the topic for your metaphor and write it down.2. Choose six of the organelles in a eukaryotic cell and make the metaphor, as I did above.3. Either write a short story (two paragraphs) about something fictional that happens with

your metaphor or make a drawing of your metaphor.

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What is Inside of a Cell?

Carrot Carrot DiffusionDiffusion

In this activity, you will be discovering how water can affect carrots by entering or leaving the cells of the carrot.

1. Get the following materials: a) Two 400 mL beakers or containers b) String c) Measuring tape or meter stick d) Salt e) Distilled water f) Triple beam balance g) Carrots

2. Fill two beakers with equal amounts of water. 3. Add 15 g salt to one beaker and label it “Salt Water”. 4. Cut a carrot in half. Tightly tie a piece of string two cm below the cut end of both pieces. 5. Place one carrot half (cut end down) in the “Salt Water” beaker. Place the other carrot

with cut end down in the “Fresh Water” beaker. 6. Form a hypothesis about what you think will happen in each beaker. 7. After 24 hours, remove carrots and observe them and the tightness of the strings. Record

data. 8. Did the thread become loose in fresh water or salt water? 9. Did the thread become tight thread in fresh water or salt water? 10.Did the carrot develop a soft texture in fresh water or salt water? 11.Did the carrot develop a firm texture in fresh water or salt water? 12.In which type of water did the carrot cells increase in cell size (freshwater or salt water?) 13.In which type of water did the carrot cells decrease in cell size (freshwater or salt water?) 14.Was there a loss of water by cells in fresh water or salt water? 15.Did the cells gain of water in either fresh water or salt water? 16.What was the purpose of having you tie thread on each carrot? 17.In which kind of water did the carrot cells lose water? 18.What evidence supports your conclusion? 19.In which kind of water did the carrot cells gain water? 20.What evidence did you use to determine this? 21.What do you think would happen to human blood cells if they were placed in a beaker of

salt water?

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