Unit 2 “Cells & Viruses” Chapter 7 & 18.2 22 Clicker Questions….. Get Ready!

Unit 2“Cells & Viruses”

Chapter 7 & 18.2

22 Clicker Questions…..

Get Ready!

Cell DiscoveryHow 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 MethodWhat 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 Theory1. 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 Einsteind. Gregory Mendel

Clicker Question #2

Which of the following best describes a theory?

a. It is an ideab. It is a statement based on an observationc. It describes a single action in science and

is accepted by all scientistsd. It is a scientifically accepted explanation

based on a hypothesis that had been proven by many scientists

Clicker Question #3Which 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.

NucleusWhat 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 TypesWhat 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 TypesWhat 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. Prokaryoteb. Eukaryotec. Plantd. 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

CytoskeletonSupporting

network

Microfilaments &

MicrotubulesPlants & Animals

Ribosomes


Golgi Apparatus

Lysosomes


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


network

Microfilaments &


Ribosomes Make proteins

Free & attached

Plants & Animals


Golgi Apparatus

Lysosomes


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


network

Microfilaments &



Free & attached

Plants & Animals


Transport system

Rough ER (ribosomes attached)

Smooth ER(No ribosomes attached)

Plants & Animals

Golgi Apparatus

Lysosomes


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


network

Microfilaments &



Free & attached

Plants & Animals


Transport system

Rough ER (ribosomes attached)

Smooth ER(No ribosomes attached)

Plants & Animals

Golgi Apparatus

Modifies & packages proteins

Create lysosomes

Plants & Animals

Lysosomes


Lysosomes• Defined: Vesicle that uses enzymes to digest

excess or worn-out cellular substances.

• Function: Digests


network

Microfilaments &



Free & attached

Plants & Animals


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

LysosomesDigests food

& dead organelles

Filled with enzymes;

“Garbage Can”Plants & Animals


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


Clicker Question #10

This organelle modifies proteins:

a. Lysosome

b. Ribosome

c. Golgi Apparatus



This organelle is filled with enzymes for digestion purposes:

a. Lysosome

b. Ribosome

c. Golgi Apparatus


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


Chloroplast• Defined: Double-membrane organelle that captures

light energy & converts it to chemical energy (glucose) through photosynthesis.

• Function: Coverts light, H2O, & CO2 into food = Photosynthesis

Vacuole

Cilia &

Flagella

MitochondriaConverts food

into energyCellular Respiration


ChloroplastMakes food

from sunlightPhotosynthesis

Plants ONLY

Cell Wall


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





from sunlightPlants ONLY

Cell Wall Supports & protects

NOT found in animals!

PlantsBacteriaFungus


Photosynthesis

Vacuole• Defined: Membrane-bound vesicle for temporary storage

of materials such as food, water, enzymes, and wastes.

• Function: Storage

Vacuole

Cilia &

Flagella









Stores water, food, & waste

Very large in plants

Plants & Animals


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

http://programs.northlandcollege.edu/biology/Biology1111/animations/flagellum.html

Vacuole

Cilia &

Flagella









Stores water, food, & waste

Very large in plants

Plants & Animals

Aids in swimming

Cilia (many hairlike)

Flagella (whip like)Plants & Animals


Photosynthesis


These are hair-like and aid cells in swimming/locomotion:

a. Cilia

b. Flagella

c. Flagellum

d. Tails


Photosynthesis occurs here:

a. Chloroplast

b. Mitochondria

c. Cell Wall

d. Vacuole


These two organelles are NOT found in animal cells:

a. Chloroplast & Mitochondriab. Cilia & Vacuolesc. Cell Wall & Chloroplastd. Mitochondria & Vacuoles


These are very large in plants and provides support when

filled with water:

a. Chloroplastb. Mitochondriac. Cell Walld. Vacuole


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

• --symbioticsymbiotic means relationship


• 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


• 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

http://www.sumanasinc.com/webcontent/animations/content/organelles.html


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


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 VirusFlu Virus Ebola Virus Bacteriaphage

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 Virus Small Pox Virus Polio Virus Herpes Virus

http://en.wikipedia.org/wiki/File:EM_smallpox,_grown_via_tissue,_isolate_by_centrifuge.jpg

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

http://www.cellsalive.com/howbig.htm

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


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


Which of the following is the smallest?

a. White blood cell

b. Pollen

c. Bacteria

d. Virus


Which of the following do viruses NOT have?

a. Organelles

b. Capsid

c. Genetic material

d. They have all of the above


DNA is located here:

a. Golgi Apparatus

b. Nucleus

c. Lysosomes

d. Vacuoles

The End

Answers1. B 6. C 11. A 16. D2. D 7. B 12. A 17. A3. A 8. C 13. A 18. D4. B 9. B 14. C 19. B5. A 10. C 15. D 20. D

21. A22. B

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Unit 2 “Cells & Viruses” Chapter 7 & 18.2 22 Clicker Questions….. Get Ready!