Unit 2 “Cells & Viruses” Chapter 7 & Clicker Questions….. Get Ready!

Cell Discovery How did cells get their name? Robert Hooke Made a simple microscope Looked at a piece of cork under his microscope Looked like little chambers in a monastery The monks lived in chambers called cells Hooke called the chambers in the cork “ cells ”

Scientific Method What is the difference between a hypothesis, theory, and a law? Theory : A theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers. One scientist cannot create a theory; he can only create a hypothesis. (Example: Theory of Relativity…pertains to gravity, time, & space) Hypothesis : This is an educated guess based upon observation. It is a rational explanation of a single event or phenomenon based upon what is observed, but which has not been proved. Most hypotheses can be supported or refuted by experimentation or continued observation. Law : In general, both a scientific theory and a scientific law are accepted to be true by the scientific community as a whole. But law describes a single action where a theory explains an entire group of related phenomena. (Example: Law of Gravity…pertains to gravity alone)

Cell Theory 1.All living organisms are composed of one or more cells. 2.Cells are the basic unit of structure and organization of all living organisms. 3. Cells arise only from previous existing cells, with cells passing copies of their genetic material on to their daughter cells.

Clicker Question #1 Who gave cells their name? a. Charles Darwin b. Robert Hooke c. Albert Einstein d. Gregory Mendel

Clicker Question #2 Which of the following best describes a theory? a.It is an idea b.It is a statement based on an observation c.It describes a single action in science and is accepted by all scientists d.It is a scientifically accepted explanation based on a hypothesis that had been proven by many scientists

Clicker Question #3 Which of the following statements is supported by the Cell Theory to identify if an amoeba is composed of a cell? a.Amoebas have the ability to split to create another genetically identical amoeba. b.Amoebas can move and hunt for food. c.Amoebas need oxygen. d.Amoebas must eat.

Nucleus What is a nucleus? A distinct central organelle that contains the cell’s genetic information in the form of DNA. Controls all of the cell’s activities

Basic Cell Types What are the two basic types of cells? 1. Prokaryotes: Cells do NOT have a nucleus or organelles. Example: ALL Bacteria…E. coli, Strep, & Salmonella How to Remember “Trick”… Pro has NO nucleus

Prokaryotes Has NO Nucleus Has Nucleoid (like a nucleus…but not a real one) Has NO organelles REMEMBER…. Pro has NO nucleus

Basic Cell Types What are the two basic types of cells? 2. Eukaryotes : Cells HAVE a nucleus and organelles. Examples: Plants, animals, fungus…All other cells How to Remember “Trick”… Eu has TRUE nucleus

Eukaryotes Has a true/real Nucleus Has many different organelles Eu has TRUE nucleus REMEMBER….

Clicker Question #4 If a cell has a nucleus, it is considered a(n): a. Prokaryote b. Eukaryote c. Plant d. Animal

Clicker Question #5 If a cell does NOT have a nucleus, it is considered a(n): a. Prokaryote b. Eukaryote c. Plant d. Animal

Clicker Question #6 Which of the following is an example of an eukaryote? a. a Virus b. Staphylococcus c. a sunflower d. HIV

Clicker Question #7 Which of the following is an example of a prokaryote? a. mushrooms b. E. coli c. an oak tree d. humans

Cell Organelles Function More Info Location Cytoskeleton Ribosomes Endoplasmic Reticulum Golgi Apparatus Lysosomes

Cytoskeleton Defined: Supporting network of protein fibers that provide a framework for the cell within the cytoplasm Function: Aids in cell & organelle movement & support 2 substructures: Mircotubules & Microfilaments

Cytoskeleton Supporting network Microfilaments & Microtubules Plants & Animals Ribosomes Endoplasmic Reticulum Golgi Apparatus Lysosomes Cell Organelles Function More Info Location

Ribosomes Defined: Simple cell organelle that helps manufacture proteins. Function: Synthesize/make proteins Turn volume down Can be found attached to E.R. or free in the cell

Cytoskeleton Supporting network Microfilaments & Microtubules Plants & Animals Ribosomes Make proteins Free & attached Plants & Animals Endoplasmic Reticulum Golgi Apparatus Lysosomes Cell Organelles Function More Info Location

Endoplasmic Reticulum Defined: Highly folded membrane system in eukaryotic cells that is the site for protein and lipid synthesis. Function: When rough (ribosomes), proteins are made here & transports

Cytoskeleton Supporting network Microfilaments & Microtubules Plants & Animals Ribosomes Make proteins Free & attached Plants & Animals Endoplasmic Reticulum Transport system Rough ER (ribosomes attached) Smooth ER (No ribosomes attached) Plants & Animals Golgi Apparatus Lysosomes Cell Organelles Function More Info Location

Golgi Apparatus Defined: Flattened stack of tubular membranes that modifies, sorts, and packages proteins into vesicles and transports them to another organelle or out of the cell. Function: Modifies and packages proteins, creates lysosomes

Cytoskeleton Supporting network Microfilaments & Microtubules Plants & Animals Ribosomes Make proteins Free & attached Plants & Animals Endoplasmic Reticulum Transport system Rough ER (ribosomes attached) Smooth ER (No ribosomes attached) Plants & Animals Golgi Apparatus Modifies & packages proteins Create lysosomes Plants & Animals Lysosomes Cell Organelles Function More Info Location

Lysosomes Defined: Vesicle that uses enzymes to digest excess or worn-out cellular substances. Function: Digests

Cytoskeleton Supporting network Microfilaments & Microtubules Plants & Animals Ribosomes Make proteins Free & attached Plants & Animals Endoplasmic Reticulum Transport system “I-75” Rough ER - Protein (ribosomes attached) Smooth ER - Lipids (No ribosomes attached) Plants & Animals Golgi Apparatus Modifies & packages proteins; creates lysosomes “UPS or Post Office” Plants & Animals Lysosomes Digests food & dead organelles Filled with enzymes; “Garbage Can” Plants & Animals Cell Organelles Function More Info Location

Clicker Question #8 This organelle is composed of microfilaments and micotubules: a. Lysosome b. Ribosome c. Cytoskeleton d. Endoplasmic reticulum

Clicker Question #9 This organelle synthesizes proteins: a. Lysosome b. Ribosome c. Cytoskeleton d. Endoplasmic reticulum

Clicker Question #10 This organelle modifies proteins: a. Lysosome b. Ribosome c. Golgi Apparatus d. Endoplasmic reticulum

Clicker Question #11 This organelle is filled with enzymes for digestion purposes: a. Lysosome b. Ribosome c. Golgi Apparatus d. Endoplasmic reticulum

Mitochondria Defined: Membrane-bound organelle that converts fuel into energy that is available to the rest of the cell. Function: Converts food into energy = Cellular respiration

Vacuole Cilia & Flagella Mitochondria Converts food into energy Cellular Respiration Powerhouse Plants & Animals Chloroplast Cell Wall Cell Organelles Function More Info Location

Chloroplast Defined: Double-membrane organelle that captures light energy & converts it to chemical energy (glucose) through photosynthesis. Function: Coverts light, H 2 O, & CO 2 into food = Photosynthesis

Vacuole Cilia & Flagella Mitochondria Converts food into energy Cellular Respiration Powerhouse Plants & Animals Chloroplast Makes food from sunlight Photosynthesis Plants ONLY Cell Wall Cell Organelles Function More Info Location

Cell Wall Defined: In plants, the rigid barrier that surrounds the outside of the plasma membrane, is made of cellulose, and provides support & protection to the cell. Function: In plants, bacteria, & fungi provides support Organism Cell Wall is made of: Plants Cellulose Bacteria Peptidoglycan Fungi Chitin

Vacuole Cilia & Flagella Mitochondria Converts food into energy Cellular Respiration Powerhouse Plants & Animals Chloroplast Makes food from sunlight Plants ONLY Cell Wall Supports & protects NOT found in animals! Plants Bacteria Fungus Cell Organelles Function More Info Location Photosynthesis

Vacuole Defined: Membrane-bound vesicle for temporary storage of materials such as food, water, enzymes, and wastes. Function: Storage

Vacuole Cilia & Flagella Mitochondria Converts food into energy Cellular Respiration Powerhouse Plants & Animals Chloroplast Makes food from sunlight Plants ONLY Cell Wall Supports & protects NOT found in animals! Plants Bacteria Fungus Stores water, food, & waste Very large in plants Plants & Animals Cell Organelles Function More Info Location Photosynthesis

Cilia & Flagella Cilia: Hair-like projections that functions in cell movement Flagella: Long tail-like projection with a whip- like motion that helps a cell swim. Flagella

Vacuole Cilia & Flagella Mitochondria Converts food into energy Cellular Respiration Powerhouse Plants & Animals Chloroplast Makes food from sunlight Plants ONLY Cell Wall Supports & protects NOT found in animals! Plants Bacteria Fungus Stores water, food, & waste Very large in plants Plants & Animals Aids in swimming Cilia (many hairlike) Flagella (whip like) Plants & Animals Cell Organelles Function More Info Location Photosynthesis

Clicker Question #12 These are hair-like and aid cells in swimming/locomotion: a. Cilia b. Flagella c. Flagellum d. Tails

Clicker Question #13 Photosynthesis occurs here: a. Chloroplast b. Mitochondria c. Cell Wall d. Vacuole

Clicker Question #14 These two organelles are NOT found in animal cells: a. Chloroplast & Mitochondria b. Cilia & Vacuoles c. Cell Wall & Chloroplast d. Mitochondria & Vacuoles

Clicker Question #15 These are very large in plants and provides support when filled with water: a. Chloroplast b. Mitochondria c. Cell Wall d. Vacuole

Clicker Question #16 Which of the following has a cell wall? a. Mushroom b. Sunflower c. E. coli d. All of the above

Endosymbiotic Theory Endosymbiotic Theory proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms. Endo- Endo- means inside - symbiotic - symbiotic means relationship

Endosymbiotic Theory Prokaryotes entered ancestral eukaryotes Prokaryotes did NOT act as a parasite by infecting the host (eukaryote) Eukaryotes did NOT digest the prokaryotes Instead, the smaller prokaryotes began LIVING inside the larger cell – giving rise to eukaryotes

Endosymbiotic Theory 1st - Mitochondria & Chloroplasts have DNA similar to bacterial DNA. 2nd – Mitochondria & Chloroplasts have ribosomes whose size & structure resembles those of bacteria. 3rd – Like bacteria, Mitochondria & Chloroplasts reproduce by binary fission when the cells containing them divide by mitosis. Click Here For Animation Tutorial

Clicker Question #17 Which of the following summarizes the Endosymbiotic Theory? a. Mitochondria & chloroplasts in eukaryotes were once prokaryotes b. Ribosomes & lysosomes in eukaryotes were once prokaryotes c. Mitochondria & chloroplasts are now found inside prokaryotes d. None of the above

Clicker Question #18 Which of the following are true? a. Mitochondria has DNA similar to prokaryotes b.Ribosomes in eukaryotes are similar to prokaryotes c. When mitochondria create more of themselves, they divide similar to how prokaryotes divide d.All of the above

Viruses Virus comes from the Latin word for “poison” Virus are particles of nucleic acid, protein, and in some cases lipids that can reproduce only by infecting living cells. Viruses are so small that they can only be seen using an electron microscope. AIDS Virus Flu Virus Ebola VirusBacteriaph age

Viruses Viruses have NO organelles! A typical virus is composed of a core of either DNA or RNA surrounded by a protein coat. Common Cold VirusSmall Pox VirusPolio VirusHerpes Virus

Viruses A virus’s outer protein coat is called its capsid. A capsid is an outer protein coat that enables a virus to enter a host cell. The capsid binds to the surface of a cell and “tricks” the cell into allowing it inside.

Viruses Once inside the cell, the viral genes take over. The cell transcribes (reads and copies) the viral genes, putting the genetic program of the virus into effect. And often times the virus destroys the host cell

Viruses Vaccine : A preparation of a weakened or killed pathogen, upon injection, stimulates antibody production or cellular immunity against the pathogen but is incapable of causing severe infection (sickness). A world wide vaccination program was able to eliminate smallpox! Antibiotics NEVER cure viral infections!!... ONLY Bacteria Click here to compare size! Small pox

Viruses Video

Bacteria (cells) Viruses Both Has an organelle (ribosomes) Reproduces on their own Has NO organelles Must have host to reproduce Large in size Extremely small in size DNA or RNA Cause disease Capsid for protection Cell wall for protection

Clicker Question #19 Which of the following statements is true about viruses? a. Viruses do not have DNA b. Viruses must have a host to reproduce c. Antibiotics kill viruses d. Viruses have organelles

Clicker Question #20 Which of the following is the smallest? a. White blood cell b. Pollen c. Bacteria d. Virus

Clicker Question #21 Which of the following do viruses NOT have? a. Organelles b. Capsid c. Genetic material d. They have all of the above

Clicker Question #22 DNA is located here: a. Golgi Apparatus b. Nucleus c. Lysosomes d. Vacuoles

The End

Answers 1. B6. C11. A16. D 2. D7. B12. A17. A 3. A8. C13. A18. D 4. B9. B14. C19. B 5. A10. C15. D20. D 21. A 22. B