how are animals airplanes - griffith public...

318

How AreAnimals & Airplanes

Connected?

How AreAnimals & Airplanes

Connected?

(background)Glenn W. Elison, (b)Stephen St. John/National Geographic Image Collection

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To find project ideas and resources, visit in6.msscience.com/unit_project.Projects include:• Technology Use your imagination to cross-breed species into new animals. Write an

adventure story with your new creature to solve a problem with other students. 6.4.4• Career Explore a biology-related career, and then write a want ad for a new job

position. 6.1.4, 6.2.5, 6.4.3, 6.4.9• Model Study an animal, its characteristics, and habitat. Design a lunch bag with your

new knowledge. A snack related to your animal may be placed inside to share withyour classmates. 6.2.6, 6.2.7, 6.4.8

Investigate Origins of Birds to learn about the theory that birds descendedfrom theropod dinosaurs. Compare and contrast bird characteristics withother animals. 6.4.8

For thousands of years, people dreamed of flying like birds. Detailed sketches of flying machines were made about 500 years ago. Many of these

machines featured mechanical wings that were intended to flap like the wingsof a bird. But human muscles are not powerful enough to make such wingsflap. Later, inventors studied birds such as eagles, which often glide throughthe air on outstretched wings. Successful gliders were built in the 1800s, butthe gliders had no source of power to get them off the ground—and they werehard to control. Around 1900, two inventors studied bird flight more carefullyand discovered that birds steer by changing the shape and position of theirwings. The inventors built an engine-powered flying machine equipped withwires that could cause small changes in the shape and position of the wings.Though hardly as graceful as a soaring bird, the first powered, controlled flighttook place in 1903, in the airplane seen here.

The assessed Indiana objective appears in blue.

Glenn W. Elison

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http://in6.msscience.com/unit_project

sections

1 The World of CellsLab Observing Algae

2 The Different Jobs of CellsLab Water Movement inPlants

Virtual Lab How do animaland plant cells work?

Life’s Building BlocksIf you look closely, you can see that thesefrogs and crocodiles are made up of small,plastic building blocks. Similarly, livingorganisms also are made up of small build-ing blocks. The building block of all livingthings is the cell.

Describe how plastic buildingblocks fit together to build a larger structure.Science Journal

Cells—The Units of Life

Academic Standard—4: Students recognize that plants and animals obtain energy in differentways, and they can describe some of the internal structures of organisms related to this func-tion. They examine the similarities and differences between humans and other species. They usemicroscopes to observe cells and recognize cells as the building blocks of all life.

Also covers: Academic Standards 1, 2, 3, 5 (Detailed standards begin on page IN8.)

(bkgd.)Dave G. Houser/CORBIS

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Compare Cells Make the fol-lowing Foldable to help you seehow plant and animal cells aresimilar and different.

Fold a verticalsheet of paper inhalf from top tobottom.

Fold in half from sideto side with the fold at the top.

Unfold the paper once. Cut only the fold of the top flap to make two tabs. Turnthe paper vertically and draw on the front tabs as shown.

Read and Write Before you read the chapter,write what you know about each of these cells.As you read the chapter, add to or correct whatyou have written under the tabs. Compare andcontrast the two types of cells.

STEP 3

STEP 2

STEP 1

Observe Onion CellsAn active, organized world is inside you andin all other living things. Yet it is a world thatyou usually can’t see with just your eyes.Make the magnifier in the lab below to helpyou see how living things are organized.

1. Cut a 2-cm hole inthe middle of anindex card. Tapea piece of plasticwrap over thehole.

2. Turn down about 1 cm of the two shorter sides of the card, then stand it up.

3. Place a piece of onion skin on a micro-scope slide, then put it directly under thehole in the card.

4. Put a drop of water on the plastic wrap.Look through the water drop and observethe piece of onion. Draw what you see.

5. Think Critically In your Science Journal,describe how the onion skin looked whenviewed with your magnifier.

Start-Up Activities

Preview this chapter’s contentand activities at in6.msscience.com

PlantCell

AnimalCell

(bkgd.)Dave G. Houser/CORBIS, (inset)Matt Meadows

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Importance of CellsA cell is the smallest unit of life in all living things. Cells

are important because they are organized structures that helpliving things carry on the activities of life, such as the break-down of food, movement, growth, and reproduction. Differentcells have different jobs in living things. Some plant cells helpmove water and other substances throughout the plant. Whiteblood cells, found in humans and many other animals, helpfight diseases. Plant cells, white blood cells, and all other cells arealike in many ways.

Cell Theory Because most cells are small, they were notobserved until microscopes were invented. In 1665, scientistRobert Hooke, using a microscope that he made, observed tiny,boxlike things in a thin slice of cork, as shown in Figure 1. Hecalled them cells because they reminded him of the small, box-like rooms called cells, where monks lived.

Throughout the seventeenth and eighteenth centuries, scien-tists observed many living things under microscopes. Theirobservations led to the development of the cell theory. The threemain ideas of the cell theory are:

1. All living things aremade of one or morecells.

2. The cell is the basicunit of life in whichthe activities of lifeoccur.

3. All cells come fromcells that alreadyexist.

The World of Cells

322 CHAPTER 11 Cells—The Units of Life

Figure 1 Robert Hooke designed this microscopeand drew the cork cells he observed.

■ Discuss the cell theory.■ Identify some of the parts

of animal and plant cells.■ Explain the functions

of different cell parts.

Cells carry out the activities of life.

Review Vocabularytheory: an explanation of thingsor events based on scientificknowledge that is the resultof many observations andexperiments

New Vocabulary

• bacteria

• cell membrane

• cell wall

• cytoplasm

• organelle

• nucleus

• vacuole

• mitochondria

• photosynthesis

• chloroplast

Standards—6.4.3: Describe . . . internal structures animals and plants have . . . to make or find food and repro-duce. 6.4.5: Investigate and explain that all living things are composed of cells . . . . 6.4.6: Distinguish the maindifferences between plant and animal cells . . . . 6.4.7: Explain that about two-thirds of the mass of a cell isaccounted for by water. . . .

Also covers: 6.1.7, 6.2.7, 6.3.17, 6.4.1, 6.4.8, 6.5.1 (Detailed standards begin on page IN8.)

The Science Museum, London

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SECTION 1 The World of Cells 323

Figure 2 All living things aremade up of cells.

E. coli—a bacterium—is a one-celled organism.

Human cells are similar to other animalcells like those in cats and turtles.

Plant cells are different from ani-mal cells.

The Microscopic Cell All the living things pictured in Figure 2 are made up of cells. The smallest organisms on Earthare bacteria. They are one-celled organisms, which means theyare made up of only one cell.

How many cells does each bacterium have?

Larger organisms are made of many cells. These cells worktogether to complete all of the organism’s life activities. The liv-ing things that you see every day—trees, dogs, insects, people—are many-celled organisms. Your body contains more than 10 trillion (10,000,000,000,000) cells.

Microscopes Scientists have viewed and studied cells forabout 300 years. In that time, they have learned a lot about cells.Better microscopes have helped scientists learn about the differ-ences among cells. Some modern microscopes allow scientists tostudy the small features that are inside cells.

The microscope used in most classrooms iscalled a compound light microscope. In

this type of microscope, light passes through the object you arelooking at and then through two or more lenses. The lensesenlarge the image of the object. How much an image is enlargeddepends on the powers of the eyepiece and the objective lens.The power—a number followed by an �—is found on eachlens. For example, a power of 10� means that the lens can mag-nify something to ten times its actual size. The magnification ofa microscope is found by multiplying the powers of the eyepieceand the objective lens.

(tr)David M. Phillips/Visuals Unlimited, (cr)Richard Shiell/Earth Scenes, (bl)Michael Keller/The Stock Market/CORBIS, (bc)Zig Leszczynski/Animals Animals, (br)Reed/Williams/Animals Animals

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Figure 3 These are some of theparts of an animal cell that performthe activities necessary for life.

What are cells made of?As small as cells are, they are made of even smaller parts, each

doing a different job. A cell can be compared to a bakery. Theactivities of a bakery are inside a building. Electricity is used torun the ovens and other equipment, power the lights, and heatthe building. The bakery’s products require ingredients such asdough, sugar, and fillings, that must be stored, assembled, andbaked. The bakery’s products are packaged and shipped to differ-ent locations. A manager is in charge of the entire operation. Themanager makes a plan for every employee of the bakery and aplan for every step of making and selling the baked goods.

A living cell operates in a similar way. Like the walls of thebakery, a cell has a boundary. Inside this boundary, the cell’s lifeactivities take place. These activities must be managed. Smallerparts inside the cell can act as storage areas. The cell also hasparts that use ingredients such as oxygen, water, minerals, andother nutrients. Some cell parts can release energy or make sub-stances that are necessary for maintaining life. Some substancesleave the cell and are used elsewhere in the organism.

Cell membrane helps controlwhat enters and leaves the cell.

Nucleus controls most of thecell’s activities.

Cytoplasm is a gelatinlike substancethat contains many chemicals that thecell needs.

Mitochondrionconverts food energyinto a form that thecell can use.

Chromosomes are in thenucleus.They contain DNA,achemical that determineswhich traits an organism willhave.

Vacuole stores food,water,minerals,andwastes.

Topic: Electron MicroscopesSome cell parts could not be seenuntil the electron microscope(EM) was invented. Visitin6.msscience.com for Weblinks to information aboutelectron microscopes.

Activity Make a pamphletdescribing an electron microscope.Include a section on cell parts thatwere first seen using an EM.

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Figure 4 Most plant cells con-tain the same types of organellesas in animal cells. Plant cells alsohave a cell wall and chloroplasts.

Outside the Cell The cell membrane, shown in Figure 3, isa flexible structure that holds the cell together, similar to thewalls of the bakery. The cell membrane forms a boundarybetween the cell and its environment. It also helps control whatgoes into and comes out of the cell. Some cells, like those inplants, algae, fungi, and many types of bacteria, also have astructure outside the cell membrane called a cell wall, shown inFigure 4. The cell wall helps support and protect these cells.

Inside the Cell The inside of a cell is filled with a gelatinlikesubstance called cytoplasm (SI tuh pla zum). Approximatelytwo-thirds of the cytoplasm is water, but it also contains manychemicals that are needed by the cell. Like the work area insidethe bakery, the cytoplasm is where the cell’s activities take place.

Organelles Except for bacterial cells, cells contain organelles(or guh NELZ) like those in Figure 3 and Figure 4. These spe-cialized cell parts can move around in the cytoplasm and per-form activities that are necessary for life. You could think ofthese organelles as the employees of the cell because each type oforganelle does a different job. In bacteria, most cell activitiesoccur in the cytoplasm.

Mitochondrion con-verts food energy into aform that the cell can use.

Cytoplasm is agelatinlike substancethat contains manychemicals that the cell needs.

Chromosomes are inthe nucleus.They containDNA,a chemical thatdetermines which traitsan organism will have.

Vacuole storesfood,water,minerals,and wastes.

Cell wall provides sup-port and protection.

Chloroplast capturesenergy from sunlightand uses it to convertcarbon dioxide andwater into food.

Nucleus controlsmost of the cell’s activities.

Cell membrane helps controlwhat enters and leaves the cell.

Phospholipids The cellmembrane is a double layerof complex molecules calledphospholipids (fahs foh LIHpudz). Research to find theelements that are in thesemolecules. Find those ele-ments on the periodic tableat the back of this book.

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The Nucleus A bakery’s manager follows a business plan tomake sure that the business runs smoothly. A business plandescribes how the business should operate. These plans couldinclude how many donuts are made and what kinds of pies arebaked.

The hereditary material of the cell is like the bakery’s manager.It directs most of the cell’s activities. In the cells of organismsexcept bacteria, the hereditary material is in an organelle calledthe nucleus (NEW klee us). Inside the nucleus are chromosomes(KROH muh zohmz). They contain a plan for the cell, similar tothe bakery’s business plan. Chromosomes contain an importantchemical called DNA. It determines which traits an organism willhave, such as the shape of a plant’s leaves or the color of your eyes.

Which important chemical determines the traitsof an organism?

Storage Pantries, closets, refrigerators, and freezers store foodand other supplies that a bakery needs. Trash cans hold garbageuntil it can be picked up. In cells, food, water, and other sub-stances are stored in balloonlike organelles in the cytoplasmcalled vacuoles (VA kyuh wohlz). Some vacuoles store wastesuntil the cell is ready to get rid of them. Plant cells usually havea large vacuole that stores water and other substances.

Energy and the CellElectrical energy or the energy in natural gas is converted to

heat energy by the bakery’s ovens. The heat then is used to bakethe breads and other bakery products. Cells need energy, too.Cells, except bacteria, have organelles called mitochondria(mi tuh KAHN dree uh)(singular, mitochondrion). An impor-tant process called cellular respiration (SEL yuh lur • res puhRAY shun) takes place inside a mitochondrion as shown inFigure 5. Cellular respiration is a series of chemical reactions in

which energy stored in foodis converted to a form ofenergy that the cell can use.This energy is released asfood and oxygen combine.Waste products of thisprocess are carbon dioxideand water. All cells withmitochondria use the energyfrom cellular respiration todo all of their work.Energy for the cell

WaterCarbon dioxide

Food

Oxygen

Modeling a CellProcedure1. Collect household materi-

als such as clay, card-board, yarn, buttons, drymacaroni, or other objects.

2. Using the objects that youcollected, make a three-dimensional model of ananimal or plant cell.

3. On a separate sheet ofpaper, make a key to thematerials in your cell model.

Analysis1. What does each part of

your cell model do?2. Have someone look at your

model. Which of the cellparts could they identifywithout using the key?

3. How could you improveyour model?

Figure 5 Inside a mitochon-drion, food energy is changedinto a form of energy that a cellcan use.Infer what happens to the waterand carbon dioxide produced bymitochondria in human cells.

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Self Check1. List the three main ideas of the cell theory.

2. Explain why the nucleus is so important to theliving cell.

3. Describe how cells get the energy they need to carry on their activities.

4. Describe the purpose of a cell membrane.

5. Think Critically Suppose your teacher gave you a slideof an unknown cell. How would you tell whether thecell was from an animal or from a plant?

SummaryImportance of Cells

• Cells are organized structures that help livingthings carry on the activities of life.

• The main ideas behind cells are described inthe cell theory.

• Microscopes helped scientists study cells.

What are cells made of?

• Different cell parts do different jobs.

Energy and the Cell

• Cells need energy to function. This energycomes mainly from cellular respiration.

• Plants, algae, and some bacteria make foodthrough photosynthesis.

6. Compare and contrast the parts of animal cells andplant cells and the jobs that they do.

Nature’s Solar Energy Factories Animalsobtain food from their surroundings. A cow grazesin a pasture. A bird pecks at worms, and a dog eatsfrom a bowl. Have you ever seen a plant eat any-thing? How do plants get energy-rich food?

Plants, algae, and many types of bacteria make food througha process called photosynthesis (foh toh SIHN thuh sus). Mostphotosynthesis in plants occurs in leaf cells. Inside these cells aregreen organelles called chloroplasts (KLOR uh plasts). Mostleaves are green because their cells contain so many chloroplasts.During plant photosynthesis, as shown in Figure 6, chloroplastscapture light energy and combine carbon dioxide from the airwith water to make food. Energy is stored in food. As the plantneeds energy, its mitochondria release the food’s energy. Thecaptured light energy is passed to other organisms when they eatorganisms that carry on photosynthesis.

Sunlight

Food

WaterCarbon dioxide

Oxygen

Figure 6 Photosynthesis cantake place inside leaf cells.

in6.msscience.com/self_check_quiz

Indiana Academic

Standard Check

6.4.3: Describe . . . internal struc-tures . . . plants have . . . to makeor find food . . . .

Where is food made in plantcells?

Gabe Palmer/The Stock Market

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Observing Algae


You might have noticed mats of green algaegrowing on a pond or clinging to the walls ofthe aquarium in your classroom. Why are algaegreen? Like plants, algae contain organellescalled chloroplasts. Chloroplasts contain a greenpigment called chlorophyll. It captures lightenergy that is needed to make food. In this lab,you’ll describe chloroplasts and otherorganelles in algal cells.

Real-World QuestionWhat organelles can be seen when viewingalgal cells under a microscope?

Goals■ Observe algal cells under a microscope.■ Identify cell organelles.

Materialsmicroscope pond watermicroscope slides algaecoverslips dropperlarge jars colored pencils

Safety Precautions

WARNING: Thoroughly wash your hands afteryou have finished this lab.

Procedure1. Fill the tip of a dropper with pond water and

thin strands of algae. Use the dropper toplace the algae and a drop of water on amicroscope slide.

2. Place a coverslip over the water drop andthen place the slide on the stage of amicroscope.

3. Using the microscope’s lowest powerobjective, focus on the algal strands.

4. Once the algal strands are in focus, switchto a higher power objective and observeseveral algal cells.

5. Draw a colored picture of one of the algalcells, identifying the different organelles inthe cell. Label on your drawing the cell wall,chloroplasts, and other organelles you can see.

Conclude and Apply1. List the organelles you found in each cell.

2. Explain the function of chloroplasts.

3. Infer why algal cells are essential to all pond organisms.

Work with three other students to create acollage of algal cell pictures complete withlabeled organelles. Create a bulletin boarddisplay about algal cells.

Matt Meadows

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SECTION 2 The Different Jobs of Cells 329

Special Cells for Special JobsChoose the right tool for the right job. You might have

heard this common expression. The best tool for a job is onethat has been designed for that job. For example, you wouldn’tuse a hammer to saw a board in half, and you wouldn’t use asaw to pound in a nail. You can think of your body cells in asimilar way.

Cells that make up many-celled organisms, like you, are spe-cialized. Different kinds of specialized cells work as a team toperform the life activities of a many-celled organism.

Types of Human Cells Your body is made up of many typesof specialized cells. The same is true for other animals. Figure 7shows some human cell types. Notice the variety of sizes andshapes. A cell’s shape and size can be related to its function.

The Different Jobs of Cells

■ Discuss how different cells havedifferent jobs.

■ Explain the differences amongtissues, organs, and organsystems.

You will understand how differenttypes of cells work together to keepyou healthy.

Review Vocabularyorganism: anything that pos-sesses all the characteristics of life

New Vocabulary

• tissue • organ system

• organ

Figure 7 Human cells come in differentshapes and sizes.

Nucleus

Bone cell

Hardenedbone

Nucleus

Nucleus

Nucleus

Stored fat

Cell membrane

Nucleus

Cell branches

Fat cells can store so much fat that the nucleus gets pushed against the cell membrane.

Skin cells are mostly flat and close together. They form a protective layer for your body.

Nerve cells are long and have many branches. This allows them to receive and deliver messages quickly.

Bone cells are surrounded by a hard substance made of calcium and phosphorus.

Muscle cells are usually long and have many fibers that can contract and relax.

Standards—6.4.6: Distinguish the main differences between plant and animal cells, such as the presence ofchlorophyll and cell walls in plant cells and their absence in animal cells. 6.4.11: Describe that human beingshave body systems for obtaining and providing energy, defense, reproduction, and the coordination of bodyfunctions.

Also covers: 6.2.5, 6.2.6, 6.2.7, 6.4.3, 6.4.5 (Detailed standards begin on page IN8.)

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Analyzing CellsProcedure1. Examine prepared slides

of human cells.2. Draw each type of cell

that you observe in yourScience Journal. Label cellparts that you can see.

Analysis1. In what ways were the

cells that you observedsimilar? How were theydifferent?

2. Hypothesize how the cells’shapes relate to their jobs.


Types of Plant Cells Like animals, plants also are made ofseveral different cell types, as shown in Figure 8. For instance,plants have different types of cells in their leaves, roots, andstems. Each type of cell has a specific job. Some cells in plantstems are long and tubelike. Together they form a systemthrough which water, food, and other materials move in theplant. Other cells, like those that cover the outside of the stem,are smaller or thicker. They provide strength to the stem.

What do long, tubelike cells do in plants?

Some leaf cells are brick shapedand contain many chloroplasts.

Most root cells are block shaped anddo not contain chloroplasts.

Many of the cells in stems are long andtube-shaped. They move water andother materials through the plant.

LM, Magnification: 900�

Magnification: 450�

SEM Magnification: 1500�

Figure 8 Plants, like animals,have specialized cells.Infer what process can occur inleaf cells but not in root cells.

(tr)Carolina Biological Supply Co./Earth Scenes, (l)R. Kessel/G. Shih/Visuals Unlimited, (br)Bruce Iverson

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Cell OrganizationHow well do you think your body would work if all the dif-

ferent cell types were just mixed together in no particular pat-tern? Could you walk if your leg muscle cells were scatteredhere and there, each doing its own thing, instead of beinggrouped together in your legs? How could you think if yourbrain cells weren’t close enough together to communicate witheach other? Many-celled organisms are not just mixed-up col-lections of different types of cells. Cells are organized into sys-tems that, together, perform functions that keep the organismhealthy and alive.

Studying SpaceAstronomers study systemsthat are found in space.The solar system is justone of many systems thatmake up the Milky WayGalaxy. Research to learnthe education requirementsand job description of anastronomer. Write a wantad for an astronomer.

RED BLOOD CELLS Each milliliter of blood contains 5 million red blood cells (RBCs). Onaverage, an adolescent has about 3.5 L of blood. On average, how many RBCs are in anadolescent’s body?

SolutionThis is what you know:

This is what you need to find out:

This is the procedure you need to use:

Check your answer:

● number of RBCs per 1 mL � 5,000,000

● 1,000 mL � 1 L

● average volume of blood in an adolescent’s body � 3.5 L

On average, how many RBCs are in an adolescent’s body, N?

● Use the following equation:N � (number of RBCs/1mL) (1,000 mL/1 L) (3.5 L of blood)

● Substitute the known valuesN � (5,000,000 RBCs/1 mL) (1,000 mL/1 L) (3.5 L of blood)N � 17,500,000,000 RBCs

● On average, there are 17.5 billion red blood cells in anadolescent’s body.

Divide 17,500,000,000 RBCs by 1,000 mL/1 L then divide thatanswer by 3.5 L, and you should get 5,000,000 RBCs/1 mL.

Solve One-Step Equations

1. Each milliliter of blood contains approximately 7,500 white blood cells. How many whiteblood cells are in the average adolescent’s body?

2. There are approximately 250,000 platelets in each milliliter of blood. How many plateletsare in the average adolescent’s body?

For more practice, visit in6.msscience.com/math_practice

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VISUALIZING LIFE’S ORGANIZATION

Blood tissueBone cell

Connectingtissue

Covering andlining tissueMuscle tissue Connecting tissue

Leg bone

Heart

Bones are organs that support the body. They also store some minerals and make blood cells.

The heart is an organ that pumps blood.

Figure 9Organs are two or more tissue types that work together.An organ performs a task that no other organ performs.


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Self Check1. Describe three types of cells that are found in the

human body.

2. Compare and contrast the cells found in a plant’s roots,stems, and leaves.

3. Explain the difference between a cell and a tissue andbetween a tissue and an organ.

4. Think Critically Why must specialized cells worktogether as a team?

SummarySpecial Cells for Special Jobs

• Plant and animal cells come in a variety ofsizes and shapes.

• The function of an animal cell can be relatedto its shape and size.

• The leaves, roots, and stems of plants aremade of different types of cells to performdifferent functions.

Cell Organization

• Many-celled organisms are organized intotissues, organs, and organ systems.

• Each organ system performs a specific func-tion that, together with other systems, keepsan organism healthy and alive.

5. Concept Map Make an events-chain concept mapof the different levels of cell organization from cell toorgan system. Provide an example for each level of organization.

Tissues and Organs Cells that are alike are organized intotissues (TIH shewz). Tissues are groups of similar cells that alldo the same sort of work. For example, bone tissue is made upof bone cells, and nerve tissue is made up of nerve cells. Blood,a liquid tissue, includes different types of blood cells.

As important as individual tissues are, they do not workalone. Different types of tissues working together can form astructure called an organ (OR gun). For example, the stomachis an organ that includes muscle tissue, nerve tissue, and bloodtissue. All of these tissues work together and enable the stomachto perform its digestive functions. Other human organs includethe heart and the kidneys.

Which term means “two or more tissue typesthat work together”?

Organ Systems A group of organs that work together to doa certain job is called an organ system. The stomach, mouth,intestines, and liver are involved in digestion. Together, theseand several other organs make up the digestive system. Otherorgan systems found in your body include the respiratory sys-tem, the circulatory system, the reproductive system, and thenervous system.

Organ systems also work together, as shown in Figure 9. Forexample, the muscular system has more than 600 muscles thatare attached to bones. The contracting cells of muscle tissuecause your bones, which are part of the skeletal system, to move.

Topic: One-Celled OrganismsVisit in6.msscience.com for Weblinks to information about whattypes of organisms are made up ofonly one cell.

Activity Create a table thatincludes images and informationabout five of these organisms.

in6.msscience.com/self_check_quiz

Indiana Academic

Standard Check

6.4.11: Describe that humanbeings have body systems forobtaining and providing energy,defense, reproduction, and thecoordination of body functions.

Which human body systemobtains and provides energy?

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http://in6.msscience.com/self_check_quiz

Design Your OwnDesign Your Own

Water Movement in PlanLs


Real-World QuestionWhen you are thirsty, you can sip water from a glass ordrink from a fountain. Plants must get their water inother ways. In most plants, water moves from thesoil into cells in the roots. Where does water travelin a plant?

Form a HypothesisBased on what you already know about howa plant functions, state a hypothesis about whereyou think water travels in a plant.

Test Your HypothesisMake a Plan1. As a group, agree upon a hypothesis and decide how you will test

it. Identify which results will support the hypothesis.

2. List the steps you will need to take to test your hypothesis. Bespecific. Describe exactly what you will do in each step. List yourmaterials.

3. Prepare a data table in your Science Journal to record yourobservations.

4. Read the entire investigation to make sure all steps are in logicalorder.

5. Identify all constants, variables, and controls of the investigation.

Follow Your Plan1. Make sure your teacher approves your plan before you start.

2. Carry out the investigation according to the approved plan.

3. While doing the investigation, record your observations andcomplete the data tables in your Science Journal.

Goals■ Design an investiga-

tion to show wherewater moves in a plant.

■ Observe how long ittakes water to move ina plant.

Possible Materialsfresh stalk of celery with

leavesclear drinking glassscissorsred food coloringwater

Safety Precautions

WARNING: Use care whenhandling sharp objectssuch as scissors. Avoid get-ting red food coloring onyour clothing.

(t)Envision/George Mattei, (b)Doug Martin

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LAB 335

Analyze Your Data1. Compare the color of the celery stalk before, during, and after the investigation.

2. Compare your results with those of other groups.

3. Make a drawing of the cut stalk. Label your drawing.

4. What was your control in this investigation? What were your variables?

Conclude and Apply1. Explain whether the results of this investigation supported your hypothesis.

2. Infer why only some of the plant tissue is red.

3. Explain what you would do to improve this investigation.

4. Predict if other plants have tissues that move water.

Write a report about your investigation.Include illustrations to show how theinvestigation was performed. Present yourreport to your class.

Morrison Photography

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SCIENCEANDSocietySCIENCE ISSUES

THAT AFFECTYOU!

Safety List Visit the link shown to the right or your media centerto learn about fire safety tips, including kitchen safety and escaperoutes in your home. Make a list and share it with your family. For more information, visit

in6.msscience.com/time

In Chicago, a young woman named Kelly iscooking pasta on her stove. Her clothes catchfire from the gas flame and, in the blink of an

eye, 80 percent of her body is severely burned.Will she survive?

Just 20 years ago, the answer to this questionprobably would have been “no.” Fortunately forKelly, science has come a long way in recentyears. Today, there’s a very good chance thatKelly might lead a long and healthy life.

Like the brain or the heart, the skin is an organ.In fact, it is the body’s largest organ, about 1/12of your total body weight. Composed of protectivelayers, skin keeps your internal structure safe fromdamage, infection, and temperature changes.

Today, just as farmers can grow crops of cornand wheat, scientists can grow human skin. How?

Tissue EngineersScientists, called tissue engineers, take a

piece of skin (no bigger than a quarter) from anundamaged part of the burn victim’s body. Theskin cells are isolated, mixed with special nutri-ents, and then they multiply in a culture dish.

After about two to three months, the tissueengineers can harvest sheets of new, smoothskin. These sheets, as large as postcards, aregrafted onto the victim’s damaged body andpromote additional skin growth.

By grafting Kelly’s own skin on her bodyrather than using donor skin—skin from anotherperson or from an animal—doctors avoid at leastthree potential complications. First, donor skinmay not even be available. Second, Kelly’s bodymight perceive the new skin cells from anothersource to be a danger, and her immune systemmight reject—or destroy—the transplant. Finally,even if the skin produced from a foreign sourceis accepted, it may leave extensive scarring.

Tissue TestingWhat else can tissue engineers grow? They

produce test skin—skin made in the lab and usedto test the effects of cosmetics and chemicals onhumans. This skin is eliminating the use of ani-mals for such tests. Also, tissue engineers areworking on ways to replace other body partssuch as livers, heart valves, and ears, that don’tgrow back on their own.

Thanks to advances in science, skin tissue is being “grown” in laboratories

A piece oftest skin isremoved fromits culture.

Custom Medical Stock Photo, Inc.

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Copy and complete the following concept map on the parts of a plant cell.

The World of Cells

1. The cell theory states that all living thingsare made of one or more cells, the cell is thebasic unit of life, and all cells come fromother cells.

2. The microscope is an instrument thatenlarges the image of an object.

3. All cells are surrounded by a cell membraneand contain hereditary material and cyto-plasm. Plant cells have a cell wall outsidethe cell membrane. Cells, except bacteria,contain organelles.

4. The nucleus directs the cell’s activities.Chromosomes contain DNA that deter-mines what kinds of traits an organismwill have. Vacuoles store substances.

5. In mitochondria, the process of cellularrespiration combines food molecules withoxygen. This series of chemical reactionsreleases energy for the cell’s activities.

6. The energy in light is captured and storedin food molecules during the process of pho-tosynthesis. Plants, algae, and some bacteriamake their own food by photosynthesis.

The Different Jobs of Cells

1. Many-celled organisms are made up of differ-ent kinds of cells that perform different tasks.

2. Many-celled organisms are organized intotissues, organs, and organ systems that per-form specific jobs to keep an organismalive.

CHAPTER STUDY GUIDE 337

surrounded by

protected by

inside the cell

types of

controls activities

storage energy

makes food

Cell membrane Cytoplasm

Parts of a Plant Cell

Mitochondria

in6.msscience.com/interactive_tutor(l)Kevin Collins/Visuals Unlimited, (r)David M. Phillips/Visuals Unlimited, Inc.

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Explain the difference between the terms in thefollowing sets.

1. mitochondria—chloroplast

2. tissue—organ

3. cell membrane—nucleus

4. organ—organ system

5. nucleus—organelle

6. cytoplasm—nucleus

7. vacuole—mitochondria

8. organ system—tissue

9. organelle—organ

10. cell wall—cell membrane

Choose the word or phrase that best answers thequestion.

11. Which of the following controls whatenters and leaves the cell?A) mitochondrionB) cell membraneC) vacuoleD) nucleus

12. Which of the following are found insidethe nucleus of the cell?A) vacuolesB) chromosomesC) chloroplastsD) mitochondria

Use the illustration below to answer questions 13 and 14.

13. Which letter is the gelatinlike substance ina cell that contains water and chemicals?A) A C) CB) B D) D

14. Which structure converts food energy to aform of energy the cell can use?A) A C) CB) B D) D

15. Which of the following terms bestdescribes the stomach?A) organelle C) organB) organ system D) tissue

16. What does photosynthesis make for aplant?A) food C) waterB) organs D) tissues

17. What does DNA do?A) makes foodB) determines traitsC) converts food to energyD) stores substances

18. Which of the following terms is the nameof a human organ system?A) protective C) photosyntheticB) growth D) respiratory

19. What cell structure helps support plants?A) cell membrane C) vacuoleB) cell wall D) nucleus

A

B

C

D

338 CHAPTER REVIEW

bacteria p. 323cell membrane p. 325cell wall p. 325chloroplast p. 327cytoplasm p. 325mitochondria p. 326nucleus p. 326

organ p. 333organ system p. 333organelle p. 325photosynthesis p. 327tissue p. 333vacuole p. 326

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CHAPTER REVIEW 339

20. Predict what would happen to a cell if thecell membrane were solid and waterproof.

21. Describe what might happen to a cell if allits mitochondria were removed.

22. Explain why cells are called the units of life.

23. Infer what kinds of animal cells might havea lot of mitochondria present.

24. Distinguish between a bacterium and aplant cell.

25. Compare and contrast photosynthesis and cel-lular respiration.

26. Make and Use Tables Copy and complete thistable about the functions of the followingcell parts: nucleus, cell membrane, mito-chondrion, chloroplast, and vacuole.

27. Concept Map Make an events-chain conceptmap of the following from simple tocomplex: small intestine, circular musclecell, human, and digestive system.

28. Identify and Manipulate Variables and ControlsDescribe an experiment you might do todetermine whether water moves into andout of cells.

29. Recognize Cause and Effect Why is the brick-like shape of some plant cells important?

30. Skit Working with three or four class-mates, develop a short skit about how aliving cell works. Have each group mem-ber play the role of a different cell part.

Functions of Cell Parts

Cell Part Function

31. Magnification A microscope has an eyepiecewith a power of 10� and an objective lens witha power of 40�. What is the magnification ofthe microscope?

32. Viruses Use a computer to make a line graphof the following data. At 37°C there are 1.0 mil-lion viruses; at 37.5°C, 0.5 milllion; at 37.8°C,0.25 million; at 38.3°C, 0.1 million; and at38.9°C, 0.05 million.

Use the graph below to answer question 33.

33. Plant Food Production Light is necessary forplants to make food. Using the graph above,determine which plant produced the most food.How much light was needed by the plant everyday to produce the most food?

Food Production in Plants

Hours of light received each day

Am

oun

t of

food

pro

du

ced

4

Plant A

16

Plant D

12

Plant C

8

Plant B

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Do not write in this book.

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The assessed Indiana standard

appears above the question.

Record your answers on the answer sheetprovided by your teacher or on a sheet of paper.

1. Which theory includes the idea that all cellscome from cells that already exist?

A the cell theory

B the microscopic theory

C the origins theory

D the tissue theory

The illustration below shows a typical animalcell.

2. Which controls all cell activities?

A E

B F

C G

D H

The illustration below shows a cell organelle.

3. Which organism would contain cells withthe organelle shown above?

A bacterium

B fly

C human

D plant

4. Which is a function of the organelle showabove?

A cell reproduction

B cellular respiration

C photosynthesis

D storage

5. Which describes plant cells that move waterthrough the plant?

A bricklike

B spiral-shaped

C stringy fibers

D tube-shaped

Water

Carbon dioxideSunlight

Oxygen Food

FG

H

E

340 INDIANA

IndianaIndianachapter chapter

6.4.5

6.4.6

6.4.3 6.4.6

6.4.6

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ISTEP+ PRACTICE 341

6. Which is a group of similar cells that do thesame sort of work?

A cytoplasm

B organ

C organelle

D tissue

7. Which illustration represents a humannerve cell?

A

B

C

D

8. The photo below shows a typical class-room microscope.

What type of microscope is this? How isthe total magnification of this microscopedetermined?

9. Name three organelles and describe theimportance of each one.

10. Explain why a caterpillar that eats a milk-weed plant uses captured light energy.

11. Blood carries oxygen to cells. Your musclecells require energy to relax and contract.Explain why your heart beats faster whenyou run.

12. Since plants can use photosynthesis tomake their own food, why would theyneed mitochondria?

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ISTEP+ PracticeISTEP+ Practice

6.4.6

6.4.3

6.4.3 6.4.6

Recall Experiences Remember to recall any hands-onexperience as you read the question. Base your answer on theinformation given on the test.

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