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Glencoe Science
Chapter Resources
Cells
Includes:
Reproducible Student Pages
ASSESSMENT
✔ Chapter Tests
✔ Chapter Review
HANDS-ON ACTIVITIES
✔ Lab Worksheets for each Student Edition Activity
✔ Laboratory Activities
✔ Foldables–Reading and Study Skills activity sheet
MEETING INDIVIDUAL NEEDS
✔ Directed Reading for Content Mastery
✔ Directed Reading for Content Mastery in Spanish
✔ Reinforcement
✔ Enrichment
✔ Note-taking Worksheets
TRANSPARENCY ACTIVITIES
✔ Section Focus Transparency Activities
✔ Teaching Transparency Activity
✔ Assessment Transparency Activity
Teacher Support and Planning
✔ Content Outline for Teaching
✔ Spanish Resources
✔ Teacher Guide and Answers
429-i-vi-MSS05-000000_CR 15.04.2004 15:32 Page i tammyb 301:goscanc:scanc429:layouts:
Glencoe Science
Photo CreditsSection Focus Transparency 2: (l) Index Stock/ASAP Ltd., (r,inset) Wanner/Eye of Science/Photo Researchers;Section Focus Transparency 3: Lester V. Bergman/CORBIS
Lab PreviewDirections: Answer these questions before you begin the Lab.
1. Why do you use the low power objective to locate cells on a slide?
2. What is a chloroplast?
If you compared a goldfish to a rose , you would find them unlike each other.Are their individual cells different also?
Comparing Cells
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Real-World QuestionHow do human cheek cells and plant cells compare?
Materialsmicroscope tap watermicroscope slide droppercoverslip Elodea plantforceps prepared slide of human cheek cells
Procedure1. In the table in the Data and Observations
section, check off the cell parts as youobserve them.
2. Using forceps, make a wet-mount slide of ayoung leaf from the tip of an Elodea plant.
3. Observe the leaf on low power. Focus onthe top layer of cells.
4. Switch to high power and focus on one cell.In the center of the cell is a membrane-bound organelle called the central vacuole.Observe the chloroplasts—the green disk-shaped objects moving around the centralvacuole. Try to find the cell nucleus. Itlooks like a clear ball.
5. Draw the Elodea cell in the space in the Dataand Observations section. Label the cell wall,cytoplasm, chloroplasts, central vacuole, andnucleus. Return to low power and remove theslide. Properly dispose of the slide.
6. Observe the prepared slide of cheek cellsunder low power.
7. Switch to high power and observe the cellnucleus. Draw and label the cell membrane,cytoplasm, and nucleus. Return to lowpower and remove the slide.
Goals■ Compare and contrast an animal cell and a plant cell.
Conclude and Apply1. Compare and contrast the shapes of the cheek cell and the Elodea cell.
2. Draw conclusions about the differences between plant and animal cells.
Hands-On Activities
Communicating Your Data
Draw the two kinds of cells on one sheet of paper. Use a green pencil to label theorganelles found only in plants, a red pencil to label the organelles found only in animals,and a blue pencil to label the organelles found in both. For more help, refer to the Science Skill Handbook.
Lab PreviewDirections: Answer these questions before you begin the Lab.
1. Why should you wear gloves during this experiment?
2. Describe a stereomicroscope.
You’re a technician in a police forensic laboratory. You use a stereomicroscopeand a compound light microscope in the laboratory. A detective just returnedfrom a crime scene with bags of evidence. You must examine each piece ofevidence under a microscope. How do you decide which microscope is the besttool to use?
Real-World QuestionWill all of the evidence that you’ve collectedbe viewable through both microscopes?
Form a HypothesisCompare the items to be examined under themicroscopes. Form a hypothesis to predictwhich microscope will be used for each itemand explain why.
Possible Materialscompound light microscopestereomicroscopeitems from the classroom—include some living or
once-living items (8)microscope slides and coverslipsplastic petri dishesdistilled waterdropper
Goals■ Learn how to correctly use a stereomicro-
scope and a compound light microscope.■ Compare the uses of the stereomicroscope
and compound light microscope.
Safety Precautions
Test Your Hypothesis
Make a Plan1. As a group, decide how you will test your
hypothesis.2. Describe how you will carry out this
experiment using a series of specific steps.Make sure the steps are in a logical order.Remember that you must place an item in the bottom of a plastic petri dish toexamine it under the stereomicroscopeand you must make a wet mount of anyitem to be examined under the compoundlight microscope. For more help, see theReference Handbook.
3. If you need a data table or an observationtable, design one on a separate sheet ofpaper.
Follow Your Plan1. Make sure your teacher approves the
objects you’ll examine, your plan, and yourdata table before you start.
2. Carry out the experiment.3. While doing the experiment, record your
Analyze Your Data1. Compare the items you examined with those of your classmates.
2. Classify the eight items you observed based on this experiment.
Conclude and Apply1. Infer which microscope a scientist might use to examine a blood sample, fibers, and live snails.
2. List five careers that require people to use a stereomicroscope. List five careers that require people to use a compound light microscope.
3. Infer how the images would differ if you examined an item under a compound light micro-scope and a stereomicroscope.
4. Determine which microscope is better for looking at large, or possibly live, items.
Communicating Your Data
Write a short description of an imaginary crime scene and the evidence found there. Sortthe evidence into two lists—items to be examined under a stereomicroscope and items tobe examined under a compound light microscope. For more help, refer to the ScienceSkill Handbook.
A microscope is a scientific tool used to see very small objects. Objects you cannot see withyour eyes alone can be seen using a microscope. In this experiment, you will look at a small lettere cut from a magazine, some thread, and a strand of hair using a compound light microscope.
StrategyYou will learn the names of the parts of a compound light microscope.You will learn how to use a compound light microscope.You will learn to prepare objects for viewing under a compound light microscope.You will examine several objects under a compound light microscope.You will determine how the lens system of a compound light microscope changes the position of
an object being viewed.
Materials microscope coverslip water nylon threadscissors dropper strands of hair wool threadmagazine
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ProcedurePart A—Using the Compound Light Microscope1. Study Figure 1. Identify the parts of your
microscope so that you will understand thedirections for this activity.
2. Cut out a small letter e from a magazineand place the letter on a microscope slide.WARNING: Use care when handling sharpobjects. Put a small drop of water on theletter and place a coverslip over the waterand the letter.
3. Place the slide on the microscope stage.Move the slide to center the letter e over thehole in the stage. Use the stage clips to holdthe slide in place.
4. Turn on the light if your microscope hasone. WARNING: Do not use direct sunlightas a light source. It can damage eyes. If itdoes not, adjust the mirror so that the lightis reflected through the eyepiece.
5. Look to see how the letter e is positionedon the slide before looking through theeyepiece. In the space for Figure 2a in Dataand Observations, draw the letter as yousee it without the aid of the microscope.
6. Click the low power objective lens (short-est, if more than one lens is present) intoposition. The lens should be directly overthe hole in the stage. Bring the lens close tothe slide using the coarse adjustment knob.NOTE: Be careful not to touch the slidewith the lens. This might break the lens andthe slide.
7. Look through the eyepiece of the micro-scope. Carefully bring the letter into focusby slowly turning the coarse adjustmentknob. If you cannot see the letter, movethe slide a little bit to be sure the letter isunder the lens. If your microscope hasonly one objective lens, proceed directly tostep 9; skip step 8.
8. Click the high power objective lens intoplace. If your microscope has a highpower objective, it will also have a fineadjustment knob. Look through the eye-piece again. Carefully bring the letter einto focus by slowly turning the fineadjustment knob. NOTE: Never turn the coarse adjustment knob when thehigh power objective lens is in place.
Click the low power objective lens backinto place before going on to step 9.
9. When the letter e is clearly visible, draw inFigure 2b the position of the letter as yousee it through the microscope. Next, movethe slide to the left as you look throughthe eyepiece. Note which way the letterappears to move. Move the slide forward.Note which way it appears to move now.
10. Remove the slide and clean it.
Part B—Preparing Microscope Slides1. Place a drop of water on a clean glass slide.
Put a strand of hair from your head and ahair from your forearm on the water drop.Place a coverslip over the drop of water andthe two different strands of hair.
2. Observe the hair using the procedure youused in Part A to observe the letter e.
3. In the space for Figure 3a in Data andObservations, draw the two hair strands asthey appear through the microscope. Labelthe hairs “head” and “arm.” Notice whichstrand appears thicker and show this differ-ence in your sketch.
4. Repeat Part B using a strand of nylonthread and a strand of wool thread. Drawand label the threads in Figure 3b in Dataand Observations.
Hands-On Activities
Data and ObservationsIn the spaces below, draw what you observed.
Questions and Conclusions1. Compare your drawing of the letter e without the microscope to your drawing of the letter
seen through the microscope. Describe how the microscope changes the position of the letter.
2. In what direction does the slide under the microscope appear to move when you move it to the left?
3. Describe the differences in thickness you observed between arm hair and head hair.
4. Describe the differences you observed between wool thread and nylon thread.
5. What is the total magnification of your microscope? (Multiply the magnification of the eye-piece lens by the magnification of the objective lens. These numbers are printed on the lenses.)
6. Describe how you would correctly prepare a microscope slide of an insect wing for viewingunder the microscope.
7. What precautions must be taken when using the high power lens?Ha
If you were asked how a tree, a fly, and you are alike, you might answer, “We are all alive.” If youcould examine each under a microscope, you might answer, “We all contain cells.” One veryimportant similarity among all living things is that each is made of very small units called cells.
StrategyYou will prepare living things for microscopic viewing.You will see that each living thing is made of cells and be able to name the parts of a cell.You will compare plant cells to animal cells.
Materials
Procedure
Part A—Observing Cork Cells1. Add a drop of water to a clean microscope
slide. Use forceps to add a small piece ofcork. Cover with a coverslip.
2. View the cork under low power magnifica-tion. Change to high power if your micro-scope has a high power lens.
3. Draw what you observe under Data andObservations, Part A. Label what you see.
Part B—Observing Frog Blood Cells1. View the prepared slide of frog blood
under low power magnification. Change tohigh power if your microscope has a highpower lens.
2. Draw what you observe under Data andObservations, Part B. Label the cell mem-brane, cytoplasm, and nucleus.
Part C—Observing Lettuce Leaf Cells1. Add a drop of water to a clean microscope
slide.2. Remove a small piece of lettuce leaf and
place it in the drop of water. Cover with acoverslip. Identify as many cell parts as youcan.
3. Under Data and Observation, Part C, drawwhat you observe. Label the cell wall,chloroplast, cytoplasm, nucleus, and vacuoles. (The nucleus may be difficult toobserve.)
Directions: Write T if the statement is true; write F if the statement is false.
1. Fungi have prokaryotic cells.
2. Most one-celled organisms are prokaryotic.
3. Plants and animals have eukaryotic cells.
4. Animal cells are enclosed in a cell wall.
5. The cell membrane is the protective layer around all cells.
Directions: Study the following diagram. Then use it to answer the questions on the lines provided.
6. a. A microscope contains one or more glass lenses. What do the lenses do to light that passes through them?
b. How does this affect the way an object appears when it reaches your eye?
7. The microscope’s objective lens has a magnification of 40✕. How many times willit magnify the specimen?
8. A microscope’s objective lens magnifies an object 40 times. The eyepiece magni-fies an additional 10 times. What is the microscope’s total magnification?
Directions: In numbers 1–4 below, a code letter has been substituted for each letter of the alphabet. To find outwhat the sentence says, use the following key to decode. it. In the key, the code letters are shown directly belowthe alphabet letter each stands for. Write the correct letter above each code letter, then read the sentence aloud.
Reinforcement22
Meeting Individual Needs
Directions: Answer the following questions on the lines provided.5. Who was the first person to look at cells with a microscope?
6. In what material did he see cells?
7. What did Schleiden and Schwann conclude about cells?
8. What instrument uses light and one or more lenses to view cells?
9. What instrument uses a magnetic field to magnify images up to 1,000,000 times?
A B C D E F G H I J K L M N O P Q R S T U V W X Y ZZ Y X W V U T S R Q P O N M L K J I H G F E D C B A
1. _____ ________________ _____ ________ ___ _________Z O O L I T Z M R H N H Z I V N Z W V L U X V O O H
2. __ _______ ____ _____ _________ _______ ___ ______________Z X V O O R H G S V Y Z H R X F M R G L U H G I F X G F I V
______ ______________ _____ ____ ______________Z M W U F M X G R L M R M Z M L I T Z M R H N
3. ________ _______ _________ ______ ___________ _______V E V I B X V O O X L N V H U I L N Z M L G S V I X V O O
4. _______ ____ ___________ _____ _______ _________G S R H R H X Z O O V W G S V X V O O G S V L I B
1. Listed below are the steps by which an active virus copies itself and destroys a cell. Number thesteps in the correct order in the blanks provided at the left.
a. The cell bursts open and hundreds of new virus particles are released. These new virus particles go on to infect other cells.
b. A specific virus attaches to the surface of a specific host cell.
c. The viral hereditary material takes control of the host cell and the cell begins to make new virus particles.
d. The hereditary material of the virus entering the host cell.
Directions: Answer the following questions using complete sentences.2. Explain what a latent virus does when it enters a cell.
3. Discuss several ways to prevent viral infections.
It’s hard to believe, but there was a time when we didn’t know anythingabout cell structure. In fact, the word cell (from the Latin word for chamber,cello) wasn’t used as a biological term until 1665. That’s when Robert Hooke,an English-born scientist, looked at a thin slice of a cork plant under a com-pound microscope he had built himself. Hooke noticed small holes sur-rounded by walls and named these tiny pores cells. After that, scientistsbelieved cells were found only in plants. But in 1839, Matthias Schleiden andTheodor Schwann, both German scientists, shared their scientific findings withone another. Schleiden had been studying plant cells and Schwann had beenstudying animal structures. Together, they compared plant and animal struc-tures and found that the structures were very similar—too similar to be acci-dental. They concluded that cells are the basic building blocks for both plantsand animals. In 1858, Rudolf Virchow took Schleiden’s and Schwann’s theoryand stated it simply: all cells come from other cells. This remains known as thecell theory.
Throughout the mid-1800s and into the 1900s, scientists continued to dis-cover more and more about cells thanks in part to Gregor Mendel’s study ofgenetics, Friedrich Miescher’s discovery of nuclein (which later became knownas DNA), and James Watson’s findings about DNA’s structure. Although manyamazing discoveries have happened in recent years, including genetic engineer-ing and gene therapy, all of it is because of the work of those early cell explorers.
Enrichment11
Meeting Individual Needs
1. How important was Hooke’s homemade microscope to the discovery of the plant cell? Explain.
2. Restate the cell theory in your own words.
3. Why do you think it took almost 200 years for scientists to formulate the cell theory?
There are many different kinds of micro-scopes. A magnifying glass is a simple micro-scope. The term microscope commonly refers to acompound light microscope. These microscopesare called compound because they are made oftwo sets of glass lenses in a tube or tubes.
The total magnifying power of a compoundlight microscope is the product of the magni-fying power of the lens in the eyepiece and themagnifying power of the lens in the objective.Most compound light microscopes can mag-nify a specimen up to 1,000 times its real size.
Microscopes allow you to see fine details.Spaces between objects that are closertogether than 0.1 mm can be seen. The abilityof a microscope to separate very small dis-tances is called resolving power. If the resolv-ing power of the lens is not good, the imagewill appear blurred.
When you look into the eyepiece of amicroscope, the circular area you see is thefield of view. When a ruler is placed across theopening on the stage, the field of view can bemeasured in millimeters.
Directions: Using the information above, complete the table by filling in the blanks.
Directions: Answer the following questions on the lines provided.
6. How do you find the total magnifying power of a microscope?
7. What would cause an image to appear blurred?
Figure 1
8. What is the width of the field of view shown above? In centimeters? ______
Directions: Study the following diagram. It shows the sizes of viruses, bacteria, and blood cells. The largest is ared blood cell. Then answer the questions that follow.
Enrichment33
Meeting Individual Needs
1. How large is the smallest virus on the diagram that affects plants?
2. What is the smallest thing shown on the diagram?
3. The smallest virus on the diagram attacks what kinds of organisms?
4. How do the rabies virus and the polio virus compare in size?
5. How large is the Streptococcus bacteria?
Red blood cell molecules?
6. Generalizing from this diagram, infer which are larger, viruses or bacteria
Part B. Concept ReviewDirections: Study the following diagrams. Write P above the plant cell and A above the animal cell. Then labelthe cells using the numbers of the correct terms from the list.
Assessment
3. nucleus
4. cell membrane
5. vacuole
6. ribosomes
7. mitochondrion
8. cell wall
9. cytoskeleton
10. endoplasmicreticulum
11. chloroplast
12. Golgi body
13. nucleolus
14. Number the events in the correct historical order in the blanks provided.
1. ________ 2. ________
Directions: Answer the following questions on the lines provided.15. List the three parts of the cell theory.
a.
b.
c.
16. Explain the difference between one-celled organisms and many-celled organisms.
17. Explain the difference between prokaryotic and eukaryotic cells.
a. Virchow hypothesized that cells divide to form new cells.
b. Hooke gave the name “cells” to the little boxes he saw under magnification.
c. The first microscope was invented.
d. Schleiden concluded that all plants are made up of cells, and Schwann concludedthat all animals are made of cells.
If this factory were a cell, it would run 24 hours a day and 7 days aweek. Just like a factory, cells use raw materials to produce what’sneeded. Like a factory, they have a control center, a source of power, anda way to move products and waste.
A Factory Analogy
Control center
Electricgenerator
Factory wall
Storage barrel
Section FocusTransparency Activity11
Transparency Activities
1. What part of the drawing directs the activities in the factory?
2. Identify the part of the drawing that provides energy to the factory.
The Dead Sea has very high salt concentrations, and people haveused it as a salt resource since ancient times. But is the Dead Seareally dead? The concentration of salt is too high for most livingthings, but bacteria like the ones below are able to live in its waters.
At Home in the SaltSection FocusTransparency Activity22
Tran
spar
ency
Act
iviti
es1. Why might ancient people have thought the Dead Sea was totallywithout life?
2. What tool would you use to show there really is life in the DeadSea?
3. Do you think the living thing pictured is simple or complex?Defend your answer.
Sneezing is an involuntary action that aids the body by clearing congestion within the nose. But sneezing also spreads germs,including cold and influenza viruses.
Thanks for sharing!Section FocusTransparency Activity33
Transparency Activities
1. What are your symptoms when you catch a cold?
2. What can you do to limit the spread of viruses?
Directions: Carefully review the diagram and answer the following questions.
Cells
1. The chromosomes are located in the ___.A cytoplasmB vacuolesC nucleusD nucleolus
2. The scientist performing this experiment wants to study inter-feron because it may work as a powerful medicine. If the scientistwanted to learn how powerful interferon is, the experiment couldbe repeated ___.F at a higher temperature H with less interferonG at a lower altitude J with more labels
3. The cell on the far right of the picture will probably soon ___.A grow C moveB divide D die