chapter 7 Cellular Structure and Function section ●3 Structures and Organelles

Before You Read -!). )DEA The eukaryotic cell contains For cells to function correctly, each part must do its job. organelles. Members of families have jobs or chores that help the whole What You’ll Learn family. On the lines below, list your family members and their differences in the structures of jobs. plant and animal cells

Read to Learn Identify the Parts Highlight Cytoplasm and Cytoskeleton each cell structure as you read The environment inside the plasma membrane is a about it. Underline the function semifl uid material called cytoplasm. Scientists once thought of each part. the organelles of eukaryotic cells fl oated freely in the cell’s cytoplasm. As technology improved, scientists discovered more about cell structures. They discovered a structure within the cytoplasm called the cytoskeleton. The cytoskeleton is a network of long, thin protein fi bers that provide an anchor for organelles inside the cell. The cell’s shape and movement depend on the cytoskeleton. Two types of protein fi bers make up the cytoskeleton. Microtubules are long, hollow protein cylinders that form a fi rm skeleton for the cell. They assist in moving substances within the cell. Microfi laments are thin protein threads that help give the cell shape and enable the entire cell or parts of the cell to move. 1. Name one cell function that takes place in organelles. Cell Structures

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Companies, a division of The McGraw-Hill © Glencoe/McGraw-Hill, Copyright All chemical processes of a typical eukaryotic cell take place in the organelles, which move around in the cell’s cytoplasm. Proteins are produced, food is transformed into energy, and wastes are processed in the organelles. Each organelle has a unique structure and function.

Reading Essentials Chapter 7 Cellular Structure and Function 75

069-082_Bio_SRE_C07_896099.indd 75 PDF Pass 3/4/10 10:11:27 AM How are plant and animal cells different? The fi gure below shows a typical plant cell and a typical animal cell. Note how many organelles are found in both types of cells. Also, note a few differences, such as the chloroplast that appears only in the plant cell. Observe that the vacuole in the plant cell is much larger than the vacuole in the animal cell.

Picture This 0LANT#ELL 2. Highlight the names of .UCLEUS #ELLWALL structures found in both .UCLEARPORE -ITOCHONDRION plant cells and animal 6ACUOLE #HLOROPLAST cells. Circle the names of .UCLEOLUS structures that are found -ICROTUBULE only in plant cells. Underline 2OUGH the names of structures that ENDOPLASMIC are found only in animal RETICULUM cells. 3MOOTH ENDOPLASMIC RETICULUM

2IBOSOME

0LASMA MEMBRANE

#YTOPLASM

'OLGIAPPARATUS

!NIMAL#ELL .UCLEUS .UCLEOLUS -ICROTUBULE

.UCLEARPORE 2OUGH -ITOCHONDRION ENDOPLASMIC RETICULUM 6ACUOLE #YTOPLASM

6ESICLE #ENTRIOLE Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Companies, a division of The McGraw-Hill © Glencoe/McGraw-Hill, Copyright ,YSOSOME 'OLGIAPPARATUS

0LASMA 2IBOSOMES 3MOOTH MEMBRANE ENDOPLASMIC RETICULUM

76 Chapter 7 Cellular Structure and Function Reading Essentials

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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Smooth ER produces complex carbohydrates andlipids. smooth endoplasmicreticulum, attached. hasnoribosomes bumps orrough places onthemembrane. Thesecond type, attach to theER’s surface. appearto create Theribosomes endoplasmic reticulum. Thisisthearea where ribosomes ER.There of Thefi are two types folded sacsandchannels to are which ribosomes attached. TIHKyuhlum)alsocalledER,rih system isamembrane of Reading Essentials What arelysosomes? What isstoredinvacuoles? oftheGolgiapparatus? What isthepurpose What attachestoroughendoplasmicreticulum? Which organelleproducesproteins? managescellprocesses? What structure also digest bacteria and viruses thatenter thecell. andviruses also digestbacteria excess orworn-out organelles andfoodparticles. Lysosomes nothave ormight cells might afewsmallvacuoles. wastes. Plantcells have normally onelargevacuole. Animal neededbyfood andothermaterial acell. canalsostore They inthecytoplasm.storage formaterials Vacuoles canstore tomembrane the environment outsidethecell. vesicles release theproteins, which move through theplasma The vesiclesthecell’s fusewith plasmamembrane. There the modifi (GAWLthe Golgi jee)apparatus. apparatus TheGolgi organelle called beusedby othercells.that will attach to Otherribosomes an fl ribosomes the nucleolus, components—RNA andprotein. Ribosomesare produced in envelope to thenucleus. move inandoutof surrounds thenucleus. Substances passthrough thenuclear the cell andcontrols protein production. A nuclear envelope cell’s (DNA) geneticmaterial isinthenucleus. DNA defi Lysosomes are vesicles thatcontain substances thatdigest Cells have vesicles calledvacuolesthatactastemporary Once proteins are created, move they to anotherorganelle, The endoplasmicreticulum, Ribosomes produce proteins two andare made of The nucleus isthecell’s structure. managing the Most of es, sorts, andpackstheproteins into sacscalledvesicles. oat freely inthecytoplasm. produce They proteins a structure located astructure insidethenucleus. Some the endoplasmicreticulum. (en duhPLAZmihk• rst type iscalledrough rst type nes hpe ellrSrcueadFnto Chapter 7Cellular andFunction Structure PDF Pass 3. Explain of DNA? What istherole 77 3/4/10 10:12:20 AM What makes up a centriole? Centrioles are organelles made of microtubules that function during cell division. They usually are found near the nucleus of the cell. Plant cells do not contain centrioles. Which organelle produces energy? Cells need energy to survive. The organelles that convert fuel particles such as sugars into usable energy are called mitochondria (mi tuh KAHN dree uh). A mitochondrion has an outer membrane and an inner membrane with many folds, as shown in the fi gure below. The membrane provides a large surface area for breaking the bonds of sugar molecules. Energy is produced when the bonds are broken. Picture This -ITOCHONDRION 4. Explain why the inner membrane has many folds.

)NNER /UTER MEMBRANE MEMBRANE

How do plant and animal cells differ? In addition to mitochondria, plant cells contain chloroplasts. Chloroplasts are organelles that capture light energy and convert it to chemical energy through a process called photosynthesis. Plants can use light energy from any light source—usually the Sun. Animal cells do not have chloroplasts and cannot use solar energy as fuel for cell processes. Plants also have cell walls. The cell wall is a mesh of fi bers that surrounds the plasma membrane. It protects and supports the cell. Plant cell walls are made of a carbohydrate known as cellulose. What are cilia and fl agella? Some animal cell surfaces have cilia or fl agella that extend beyond the plasma membrane. Cilia are short projections 5. Recall What is another that look like hairs. They move back and forth, similar to function of microtubules?

the motion of the oars of a rowboat. Flagella are longer, Inc. Companies, a division of The McGraw-Hill © Glencoe/McGraw-Hill, Copyright whiplike projections that propel cells. Both cilia and fl agella are composed of microtubules. They move cells through their watery environments. Cilia also move substances along the surface of the cell.

78 Chapter 7 Cellular Structure and Function Reading Essentials

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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Reading Essentials Organelles atWork Comparing Cells to doto make thecell functionproperly. asoccermember team, of each thecell.vesicles andsentto other organelles oroutof Like each are apparatus. sentto theGolgi There are they packaged in freely inthecytoplasm. Most proteins madeontherough ER thatfl ontherough ERandtheribosomes the ribosomes inthenucleus.which begins Protein synthesiscontinues with functions. proteins isamajorcell Thesynthesisof function, cells. organelles foundineukaryotic described. Note the thatprokaryotic cells lackmostof plant andanimalcells. each structureis Thefunctionof Cell Structure hools site where photosynthesis occurs Cilia Chloroplast Centriole Cell wall Vacuole both Ribosome controls themovement ofsubstances inandoutofthecell Plasma membrane suppliesenergy to therest ofthecell Nucleus Mitochondrion modifi Lysosome apparatus Golgi Flagellum aframework for thecell withinthecytoplasm reticulum (ER) Endoplasmic Cytoskeleton The structures inthecell work together to cell perform eukaryotic The tablebelow of thestructures summarizes important incell division important stores materials temporarily produces proteins animalcells only forcontains substance digestive break enzymes down aids inmoving andfeeding thecell site ofprotein synthesis; where ribosomesattach surface ofthecell surface directs the production ofproteins theproduction andcelldirects division aids inmoving thecell andmoving substances alongthe plantcells andsupports protects e n akgspoen o itiuinotietecl both proteins fores andpackages distributionoutsidethecell cell hasaspecifi structure Function oat oat c task hpe ellrSrcueadFnto Chapter 7Cellular andFunction Structure PDF Pass 6. Highlight Picture This 7. Identify function. to whichribosomesattach. plant cell—one plant cells only animal cells only both both some animalcells cell—a few small large; animal both some animalcells plant cells only both both Plant/Animal Cells amajorcell Present in the organelle 79 3/4/10 10:13:02 AM