specialized cells q and a

Viewing CellsViewing Cells

• The first microscope was made by a Dutch optometrist.

• He put two magnifying glasses together in a tube and got an image that was larger than the image that was made by either lens alone.

Viewing CellsViewing Cells

• In the mid 1600s, Antonie van In the mid 1600s, Antonie van Leeuwenhoek, a Dutch fabric merchant, Leeuwenhoek, a Dutch fabric merchant, made a simple microscope with a tiny made a simple microscope with a tiny glass bead for a lens. glass bead for a lens.

• These crude early microscopes eventually led to the types of microscopes that scientists use today.

Development of the Cell TheoryDevelopment of the Cell Theory

• In 1665, Robert Hooke cut a thin slice of cork and looked at it under his microscope.

• To Hooke, the cork seemed to be made up of empty little boxes, which he named cells.


• In the 1830s, Matthias Schleiden used a In the 1830s, Matthias Schleiden used a microscope to study plant parts. microscope to study plant parts.

• He concluded that all plants are made of cells.

• Theodor Schwann, after observing many different animal cells, concluded that all animals also are made up of cells.


• Several years later, Rudolf Virchow hypothesized that cells divide to form new cells.

• Virchow proposed that every cell came from a cell that already existed.

•His observations and conclusions and those of others are summarized in the cell theory.

Cellular OrganizationCellular Organization

• Scientists have found that cells can be Scientists have found that cells can be separated into two groups. separated into two groups.

• Cells without membrane-bound structures Cells without membrane-bound structures are called are called prokaryoticprokaryotic (proh kayr ee AH (proh kayr ee AH tihk) cells. tihk) cells.

Cellular OrganizationCellular Organization

• Cells with membrane-bound structures Cells with membrane-bound structures are called are called eukaryoticeukaryotic (yew kayr ee AH (yew kayr ee AH tihk) cells. tihk) cells.

• All cells must All cells must constantly take in constantly take in nutrients, store, nutrients, store, produce, and produce, and breakdown breakdown substances, and take substances, and take in and use energy. in and use energy.

Cell WallCell Wall• The cells of plants, algae, fungi, and most The cells of plants, algae, fungi, and most

bacteria are enclosed in a cell wall. bacteria are enclosed in a cell wall.

• Cell wallsCell walls are tough, rigid outer are tough, rigid outer coverings that protect cells and give them coverings that protect cells and give them shape. shape.

• A plant cell wall is A plant cell wall is mostly made up of a mostly made up of a carbohydrate called carbohydrate called cellulose. cellulose.

Cell WallCell Wall

• Cell walls also may contain Cell walls also may contain pectinpectin and and ligninlignin. .

• Pectin aids in cell growth, development, Pectin aids in cell growth, development, defense, and strength. defense, and strength.

• Lignin is a compound that makes cell Lignin is a compound that makes cell walls rigid. walls rigid.

Cell MembraneCell Membrane• The protective layer surrounding every The protective layer surrounding every

cell is the cell is the cell membranecell membrane. .

• The cell membrane regulates interactions The cell membrane regulates interactions between the cell and its environment. between the cell and its environment.

• The cell membrane The cell membrane allows nutrients to allows nutrients to move into the cell, move into the cell, while waste products while waste products leave. leave.

CytoplasmCytoplasm

• Cells are filled with a gelatinlike Cells are filled with a gelatinlike substance called substance called cytoplasmcytoplasm (SI toh pla (SI toh pla zuhm) that constantly flows inside the cell zuhm) that constantly flows inside the cell membrane. membrane.

• Most of a cell’s life processes occur in the Most of a cell’s life processes occur in the cytoplasm. cytoplasm.

CytoplasmCytoplasm

• Throughout the cytoplasm is a framework Throughout the cytoplasm is a framework called the called the cytoskeletoncytoskeleton, which helps the , which helps the cell maintain or change its shape and cell maintain or change its shape and enables some cells to move.enables some cells to move.

• The cytoskeleton is made up of thin, The cytoskeleton is made up of thin, hollow tubes of protein and thin, solid hollow tubes of protein and thin, solid protein fibers. protein fibers.

Manufacturing ProteinsManufacturing Proteins

• One substance that takes part in nearly One substance that takes part in nearly every cell activity is protein. every cell activity is protein.

• ProteinsProteins are part of cell membranes and are part of cell membranes and are needed for chemical reactions that are needed for chemical reactions that take place in the cytoplasm. take place in the cytoplasm.

Manufacturing ProteinsManufacturing Proteins

• Cells make their own proteins on small Cells make their own proteins on small structures called structures called ribosomesribosomes. .

• Ribosomes receive directions from the Ribosomes receive directions from the hereditary material on how, when, and in hereditary material on how, when, and in what order to make specific proteins. what order to make specific proteins.

Membrane-Bound OrganellesMembrane-Bound Organelles

• Within the cytoplasm of eukaryotic cells Within the cytoplasm of eukaryotic cells are structures called are structures called organellesorganelles,, the the largest of which is usually the nucleus. largest of which is usually the nucleus.

• Most organelles, are surrounded by a Most organelles, are surrounded by a membrane. membrane.

• Ribosomes are considered organelles, but Ribosomes are considered organelles, but are not membrane-bound. are not membrane-bound.

NucleusNucleus

• All celluar activities are directed by the All celluar activities are directed by the nucleusnucleus. .

• The nucleus contains long, threadlike, The nucleus contains long, threadlike, hereditary materials made of hereditary materials made of DNADNA. .

• DNA is the chemical that contains the DNA is the chemical that contains the code for cell’s structure and activities. code for cell’s structure and activities.

NucleusNucleus• A structure called a A structure called a nucleolusnucleolus also is also is

found in the nucleus, and is where most found in the nucleus, and is where most ribosomes are made in a eukaryotic cell. ribosomes are made in a eukaryotic cell.

Organelles That Process EnergyOrganelles That Process Energy• In plant cells, food is made in green In plant cells, food is made in green

organelles in the cytoplasm called organelles in the cytoplasm called chloroplastschloroplasts (KLOR uh plasts). (KLOR uh plasts).

• Chloroplasts contain the green pigment Chloroplasts contain the green pigment chlorophyll. chlorophyll.

•Chlorophyll captures light energy that is Chlorophyll captures light energy that is used to make a used to make a sugarsugar called called glucoseglucose, and , and turns this light energy to chemical energy.turns this light energy to chemical energy.

•The energy in food is stored until it is The energy in food is stored until it is released, usually by released, usually by mitochondriamitochondria

Organelles That Process EnergyOrganelles That Process Energy• MitochondriaMitochondria (mi tuh KAHN dree uh) (mi tuh KAHN dree uh)

(singular, mitochondrion), are organelles (singular, mitochondrion), are organelles where energy is released when food is where energy is released when food is broken down into carbon dioxide and broken down into carbon dioxide and water. water.

Organelles That Process, Transport, and Organelles That Process, Transport, and StoreStore

• EndoplasmicEndoplasmic reticulumreticulum is a series of is a series of folded membranes in which materials can folded membranes in which materials can be processed and moved around inside of be processed and moved around inside of the cell. the cell.


• The ER may be “rough” or “smooth.” The ER may be “rough” or “smooth.”

• Ribosomes are attached to areas on the Ribosomes are attached to areas on the rough ER. rough ER.

• There they carry out their job of making There they carry out their job of making proteins that are moved out of the cell or proteins that are moved out of the cell or used within the cell. used within the cell.

• Smooth ER processes cellular substances Smooth ER processes cellular substances such as lipids that store energy.such as lipids that store energy.


• After proteins are made in a cell, they are After proteins are made in a cell, they are transferred to another type of cell transferred to another type of cell organelle called the Golgi (GAWL jee) organelle called the Golgi (GAWL jee) bodies. bodies.

• The The Golgi bodiesGolgi bodies are stacked, flattened are stacked, flattened membranes. membranes.


• The Golgi bodies sort proteins and other The Golgi bodies sort proteins and other cellular substances and package them into cellular substances and package them into membrane-bound structures called membrane-bound structures called vesicles. vesicles.


• A vacuole can store water, waste A vacuole can store water, waste products, food, and other cellular products, food, and other cellular materials. materials.

• Cells also have membrane-bound spaces Cells also have membrane-bound spaces called called vacuolesvacuoles for the temporary storage for the temporary storage

of materials.of materials.

Organelles That RecycleOrganelles That Recycle

• Organelles called Organelles called lysosomes lysosomes (LI suh (LI suh sohmz) contain digestive chemicals that sohmz) contain digestive chemicals that help break down food molecules, cell help break down food molecules, cell waste, and worn-out cell parts. waste, and worn-out cell parts.

• LysosomesLysosomes also break down viruses and also break down viruses and bacteria taken into a cell. bacteria taken into a cell.

Organelles That RecycleOrganelles That Recycle• Chemicals can be released into vacuoles Chemicals can be released into vacuoles

when needed to break down its content. when needed to break down its content.

• The lysosome’s membrane prevents the The lysosome’s membrane prevents the digestive chemicals inside from leaking digestive chemicals inside from leaking into the cytoplasm and destroying the into the cytoplasm and destroying the cell. cell.

•When a cell dies, the lysosome’s When a cell dies, the lysosome’s membrane disintegrates, releasing digestive membrane disintegrates, releasing digestive chemicals that allow the quick breakdown chemicals that allow the quick breakdown of the cell’s contents.of the cell’s contents.

Many-Celled Organisms Many-Celled Organisms

• Cells in a many-celled organism do not Cells in a many-celled organism do not work alone. work alone.

• Each cell carries on its own life functions Each cell carries on its own life functions while depending in some way on other while depending in some way on other cells in the organism. cells in the organism.

•A A tissuetissue is a group of similar cells that is a group of similar cells that work together to do one job.work together to do one job.

•Tissues are organized into Tissues are organized into organsorgans..

Many-Celled Organisms

• A group of organs working together to perform a certain function is an organ system.

• Organ systems work together to make up a many-celled organism.

•An organ is a structure made up of two or more different types of tissues that work

together.

What are viruses?What are viruses?

• A A virusvirus is a strand of hereditary material is a strand of hereditary material surrounded by a protein coating.surrounded by a protein coating.

• A virus multiplies by making copies of A virus multiplies by making copies of itself with the help of a living cell called a itself with the help of a living cell called a host cellhost cell. .

• Viruses don’t have a nucleus, other Viruses don’t have a nucleus, other organelles, or a cell membrane. organelles, or a cell membrane.

Active VirusesActive Viruses

• When a virus enters a cell and is active, it When a virus enters a cell and is active, it causes the host cell to make new viruses. causes the host cell to make new viruses.

• This process destroys the host cell. This process destroys the host cell.

Latent VirusesLatent Viruses• Some viruses can be inactive, and are Some viruses can be inactive, and are

called latent. called latent.

• It does not immediately make new viruses It does not immediately make new viruses or destroy the cell.or destroy the cell.

• A virus can be latent for many years.A virus can be latent for many years.

• Then, at any time, certain conditions, Then, at any time, certain conditions, either inside or outside the body, can either inside or outside the body, can activate the virus. activate the virus.

How do viruses affect organisms?How do viruses affect organisms?• Most viruses can infect only specific Most viruses can infect only specific

kinds of cells. kinds of cells.

• A few viruses affect a broad range of A few viruses affect a broad range of hosts. hosts.

• An example of this is the rabies virus. An example of this is the rabies virus.

•A virus cannot move by itself, but it can A virus cannot move by itself, but it can reach a host’s body in several ways.reach a host’s body in several ways.

•It can be carried onto a plant’s surface by It can be carried onto a plant’s surface by the wind or it can be inhaled by an animal.the wind or it can be inhaled by an animal.

How do viruses affect organisms?How do viruses affect organisms?

• In a viral infection, the virus first attaches In a viral infection, the virus first attaches to the surface of the host cell. to the surface of the host cell.

• Viruses and the attachment sites of the Viruses and the attachment sites of the host cell must match exactly, like a host cell must match exactly, like a puzzle. puzzle.

• That’s why most viruses infect only one That’s why most viruses infect only one kind of host cell. kind of host cell.

Treating and Preventing Viral DiseasesTreating and Preventing Viral Diseases

• AntibioticsAntibiotics do not work against viral do not work against viral diseases. diseases.

• Antiviral drugsAntiviral drugs are not widely used are not widely used because of adverse side effects.because of adverse side effects.

• PreventionPrevention is the best way to fight the is the best way to fight the diseases. diseases.

Treating and Preventing Viral Diseases

• Public health measures for viral diseases include vaccinating people, improving sanitary conditions, separating patients with diseases, and controlling animals that spread the disease.

Natural ImmunityNatural Immunity

• InterferonsInterferons are proteins that protect cells are proteins that protect cells from viruses. from viruses.

• These proteins are produced rapidly by These proteins are produced rapidly by infected cells and move to noninfected infected cells and move to noninfected cells in the host.cells in the host.

• They cause the noninfected cells to They cause the noninfected cells to produce protective substances. produce protective substances.

VaccinesVaccines

• A A vaccinevaccine is made from weakened virus is made from weakened virus particles that cause your body to produce particles that cause your body to produce interferons to fight the infection. interferons to fight the infection.

• Edward Jenner is credited with Edward Jenner is credited with developing the first vaccine in 1796. developing the first vaccine in 1796.

Research with VirusesResearch with Viruses

• Scientists are discovering helpful uses for Scientists are discovering helpful uses for some viruses through research. some viruses through research.

• One use, called gene therapy, is being One use, called gene therapy, is being tried on cells with defective hereditary tried on cells with defective hereditary material. material.

•Normal hereditary material is enclosed in Normal hereditary material is enclosed in viruses.viruses. •The viruses then “infect” defective cells, The viruses then “infect” defective cells, taking the new hereditary material into the taking the new hereditary material into the cells to replace the defective material.cells to replace the defective material.

Research with VirusesResearch with Viruses• An active area of viral research is An active area of viral research is

HIV/AIDSHIV/AIDS research. research.

• HIVHIV stands for human immuno- stands for human immuno-deficiency virus, a virus that attacks deficiency virus, a virus that attacks the immune system. the immune system.

•AIDSAIDS occurs worldwide, with 95 percent occurs worldwide, with 95 percent of the cases in developing countries.of the cases in developing countries.

•Currently, there is no known cure for Currently, there is no known cure for AIDS.AIDS.

MULTIPLE CHOICEMULTIPLE CHOICE

1. ____Rough endoplasmic reticulum has 1. ____Rough endoplasmic reticulum has _____attached to it._____attached to it.

A. RibosomesA. Ribosomes

B. Golgi bodiesB. Golgi bodies

D. LysosomesD. Lysosomes

C. ChloroplastsC. Chloroplasts

AA


2. ____All of these are ways to prevent 2. ____All of these are ways to prevent viral infections EXCEPT_______.viral infections EXCEPT_______.

A. VaccinesA. Vaccines

B. Good sanitary conditionsB. Good sanitary conditions

D. Controlling animals that spread the D. Controlling animals that spread the diseasedisease

C. AntibioticsC. AntibioticsCC


3. ____When you receive a vaccine, your 3. ____When you receive a vaccine, your body produces _______ to help fight the body produces _______ to help fight the infection.infection.

A. Weakened virusesA. Weakened viruses

B. InterferonsB. Interferons

D. AntibioticsD. Antibiotics

C. Golgi bodiesC. Golgi bodies

BB


4. ____A group of cells that work together 4. ____A group of cells that work together to do one job is called.to do one job is called.

A. Organ systemA. Organ system

B. One celled organismB. One celled organism

D. OrganD. Organ

C. TissueC. TissueCC


5. ____Your heart is an example of an____.5. ____Your heart is an example of an____.

A. TissueA. Tissue

B. OrganB. Organ

D. Organ systemD. Organ system

C. CellC. Cell

BB


6. ____Latent viruses do all of these 6. ____Latent viruses do all of these EXCEPT________.EXCEPT________.

A. Destroy the host cell immediatelyA. Destroy the host cell immediately

B. Make copies of their hereditary material B. Make copies of their hereditary material as the host cell reproduces.as the host cell reproduces.

D. Insert their hereditary material into the D. Insert their hereditary material into the hereditary material of its host.hereditary material of its host.

C. Enter a host cell by means of its cell C. Enter a host cell by means of its cell membrane.membrane.

AA

MATCHINGMATCHINGA.A. Cell wallCell wall

J. CytoplasmJ. CytoplasmK. NucleusK. NucleusL. Golgi bodyL. Golgi body

I. ChloroplastI. Chloroplast H. Endoplasmic reticulumH. Endoplasmic reticulumG. OrganismG. Organism

F. Active virusF. Active virusE. Cell membraneE. Cell membraneD. RibosomeD. RibosomeC. Host cellC. Host cellB. MitochondrionB. Mitochondrion

7. ___Directs all cell activities7. ___Directs all cell activities8. ___Makes proteins8. ___Makes proteins

9. ___Protects a cell and gives it it’s shape9. ___Protects a cell and gives it it’s shape10. __Uses light energy to make sugar10. __Uses light energy to make sugar

KK

AA

IIDD





11. ___Where energy is released when food 11. ___Where energy is released when food is broken down into carbon and wateris broken down into carbon and water

12. ___Sorts and packages materials and 12. ___Sorts and packages materials and moves them out of the cellmoves them out of the cell

KK

AA

IIDD

BB

LL





13. ___Process materials and move them 13. ___Process materials and move them around inside the cell.around inside the cell.

14. ___Regulates interactions between the 14. ___Regulates interactions between the cell and its environmentcell and its environment

KK

AA

IIDD

BB

LLEE

HH





15. ___Makes copies of viral DNA15. ___Makes copies of viral DNA

16. ___Causes the host to produce new 16. ___Causes the host to produce new viruses like it selfviruses like it self

KK

AA

IIDD

BB

LLEE

HH

FF

CC





17. ___Needs a place to live, a food source, 17. ___Needs a place to live, a food source, and water.and water.

18. ___Constantly flows inside the cell18. ___Constantly flows inside the cell

KK

AA

IIDD

BB

LLEE

HH

FF

CCJJ

GG

SHORT ANSWERSHORT ANSWER19. Study the diagram below. One is 19. Study the diagram below. One is prokaryotic. The other is eukaryotic. Label prokaryotic. The other is eukaryotic. Label each cell in the spaces below the diagram. each cell in the spaces below the diagram. Identify each part with the corresponding Identify each part with the corresponding letter shown.letter shown.

cell wallcell wallcell membranecell membrane

nucleusnucleus

eukaryoticeukaryoticprokaryoticprokaryotic

hereditary hereditary materialmaterial

endoplasmic endoplasmic reticulumreticulumribosomesribosomes

Golgi bodyGolgi body

mitochondrionmitochondrion

20. Compare and contrast a latent virus 20. Compare and contrast a latent virus with an active viruswith an active virus

A latent virus is inactive and does not A latent virus is inactive and does not immediately destroy its host cell. An active immediately destroy its host cell. An active virus does immediately destroy its host cell. virus does immediately destroy its host cell. A latent virus can become active at any A latent virus can become active at any time.time.

answeranswer

specialized cells q and a

Technology

cell membranes

cell wall cell walls

cytoplasm cells

cell growth

cell activity

plant cells

cells structure

cells of plants