Exploring the Cell-iverse

by Sijie Mao

What are Cells?What are cells?- the smallest form of living things- make up all living things

In order to survive, most cells must be able to:- move- reproduce- maintain proper levels of chemicals- consume food- gain energy from food- recycle materials- get rid of waste - make proteins- adapt to their environment

What do they do?

A cell’s job or function, can differ depending on what kind it is:- a uni-cellular organism- a cell part of multi-cellular organism•in a muli-cellular organism, cells may transport oxygen throughout your body (red blood cells), they may also produce enzymes for digestion (pancreatic cell) and work together to form muscle and allow you to move (muscle cells)

Basic Structure- all cells have a cell membrane- many cells also have a cell wall- many cells have a nucleus- all cells have cytoplasm, which includes all of the cell’s contents (ie: organelles, “mini organs” of the cell) outside of its nucleus

Are all cells the same?Are all cells the same?

All living things are made up of cells either as uni-cellular (one-celled), a bacteria cell, or multi-cellular (many-celled) organisms, a squirrel As cells serve many different functions, they cell should also be expected to have different shapes and sizes. - cells range from 0.0001 mm wide as bacteria to 3 m long as nerve cells - some cells have cube, rod or spherical shape (bacteria) while others have an ever-changing shape (animal cells)

all cells are either prokaryotes or eukaryotes

ProkaryotesProkaryotes have:- no nucleus, but posesses a nucleoid- cytoplasm in which contents are scattered (no membrane-bound organelles)- a simple structure- a cell wall - cell membrane- no cytoskeleton

The following are prokaryotic cells:- bacteria cells

Eukaryotes have:- a nucleus- many membrane-bound organelles contained in the cytoplasm- cytoskeleton- more complex structure than prokaryotes (also larger than prokaryotes)- a cytoskeleton

The following are eukaryotic cells:- animal cells- plant cells- protist cells- fungi cells

Test your knowledge of cells with this quiz.

Eukaryotes

Tour of the Plant Cell

Tour of the Animal Cell

The Plasma MembraneWhat is it?- the skin of the cell- a selectively-permeable (only some things can pass through) fluid-y membrane that surrounds the whole cell- found in all cells

What is it made of?- two layers of phospholipids called the lipid bilayer- proteins

What does it do?- holds the cell together- keeps all of the cell’s contents inside- separates the cell from its environment- controls what enters and leaves (ie: waste) the cell- protection

Transport through the Plasma Membrane

Transport of Small Materials- requires no energy, uses diffusion (materials try to move across the membrane to an area of lower concentration of itself)- travel through proteins that create small openings on the plasma membrane

Transport of Large Materials- requires energy (active transport)- phagocytosis (transport into the cell): part of the plasma membrane breaks off and form a pocket around the materials, then fuses back into the membrane, bringing the materials in- exocytosis (out of the cell): materials are enclosed in a membrane bubble (vesicle) for transport by organelles in the cell, fuses with the plasma membrane, forcing the materials out

Lipids- all lipids contain a hydrophyllic (attracted to water) and hydrophobic (repelled by water) end

Bilayer- each side of the membrane facing the fluid of the interior/exterior of the cell are the hydrophyllic ends of the lipids - while the ends of the lipids that are hydrophobic stay in between, away from the fluid in/around the cell

Membrane Shape- because the hydrophyllic ends of the lipids, the lipids tend to move around as fluid moves, causing the cell membrane to be fluid-like, with an ever-changing shape

The Lipid Bilayer

The Cell WallWhat is it?-a lining around the cell, containing small holes to allow materials to enter or exit- found only in plant cells

What is it made of?-mainly made of cellulose, a flexible elastic-y material * cellulose is a carbohydrate fiber- also made of protein fibers

What does it do?- protection- gives cells a stiffer form, a defined shape- provides support- prevents collapse of cell when contents expand or shrink- keeps the cell’s contents inside the cell

The CytoskeletonWhat is it?- the skeleton and muscles of the cell- a series/web of tubes and filaments found throughout the cell- found in eukaryotic cells

What is it made of?- three types of protein fibers:•microtubules•microfilaments•intermediate filaments

What does it do?- helps maintain the shape of the cell, support- allows movement in the cell (moving of organelles and the entire cell)

The Endoplasmic ReticulumWhat is it?- the production facilility/line of the cell- a series of membranes that are an extension of the nuclear membrane - found in eukaryotic cells

What is it made of?- a series of membranes

What does it do?-there are two types:•rough endoplasmic reticulum: has ribosomes, the area where proteins are made, forms transition vesicles (a bubble-like sac that envelopes the proteins and transports them to the golgi apparatus or plasma membrane)•smooth endoplasmic reticulum: lacking ribosomes, makes enzymes to make and break down lipids and other nutrients and protect the cell from toxins

The NucleusWhat is it?- the control center or brain of the cell - a large structure surrounded by two membranes (the nuclear envelope)- found in eukaryotic cells

What is it made of?- a nuclear envelope controls what enter and leave the nucleus, pores on the envelope allow entry/exit- chromatin (DNA bound to proteins)

What does it do?- area where RNA (carries commands from the nucleus) is made- where ribosomes are made (the nucleolus)- makes instructions/commands for other areas in the cell- controls cell function- stores most of the genetic code (DNA, the cell’s identity)

CentriolesWhat is it?- a pair of cylindrical structures near the nucleus- found in animal cells

What is it made of?- each made of microtubules built into a shape of a cylinder

What does it do?- helps in cell division by separating chromosomes to opposite ends of the cell- forms cilia and flagella in cells

RibosomesWhat is it?- if the cell was a factory, ribosomes would be the machinery that produces products- small spherical structures on the rough endoplasmic reticulum or moving in the cytoplasm- found in all cells

What is it made of?- proteins and RNA

What does it do?- changes the information carried by RNA into proteins (makes proteins)- ribosomes attached to the surface of the rough endoplasmic reticulum produce proteins for transport outside the cell, lysosomes and the plasma membrane- free-moving ribosomes in the cytosol, make/provide proteins for the cytoplasm

PeroxisomesWhat is it?- a spherical membrane-bound organelle- found in eukaryotic cells

What is it made of?-proteins- filled with enzymes

What does it do?- makes and breaks down toxins used for digestion- protects cell from its own toxins/ digestive enzymes

LysosomesWhat is it?- the stomach of the cell- a spherical membrane-bound organelle made by the golgi apparatus - found in animal cells

What is it made of?- proteins- filled with various kinds of enzymes

What does it do?- breaks down un-needed materials (ie: organelles that have stopped working) in the cell- breaks down food (helps in digestion)- breaks down foreign materials (ie: bacteria)- can seal wounds in the plasma membrane when it fuses to the membrane to allow materials to exit

PlastidsWhat is it?- membrane-bound organelles that store things- found in plant cells and some protist cells

What is it made of?- lipids (fat), protein membranes

What does it do?There are three types of plastids:ChloroplastChromoplast•a membrane-bound organelle •stores carotenoid (red, orange and yellow pigment) and chlorophyll (green pigment)Leucoplast•a color-less membrane-bound organelle•changes sugar into starch to be stored•stores starches

ChloroplastWhat is it?- a green membrane-bound, organelle

What is it made of?- possibly was originally a bacteria cell - contains chlorophyll, a pigment that makes chloroplast green- contains three membranes• a smooth, permeable (anything can go through) outer membrane• a smooth inner membrane that controls what enters and exits (selectively permeable)• thylakoid membranes (a sac-like structure)

What does it do?- chlorophull makes sugar/food from abosorbed light energy (performs photosynthesis)

MitochondriaWhat is it?- the power plant of the cell, the intestines (where food is further broken down)- membrane-bound organelle covered in two membranes- found in eukaryotic cells

What is it made of?- possibly originally a bacteria cell• contains cristae on the wrinkly inner membrane•smooth outer membrane- contains own DNA

What does it do?- turns food into energy (ATP) that the cell can use more quickly to function- recycles and breaks down nutrients/un-needed materials

The Golgi ApparatusWhat is it?- the packaging plant also where final touches are made on the products- series of membranes located between the endoplasmic reticulum and the surface of the cell

What is it made of?- enzymes that allow the golgi to do its job

What does it do?- adds lipids and carbohydrates to proteins to make more complex materials - packages the materials into shuttle vesicles (portions of the golgi which pinch off, carrying the proteins for transport through the cell to other organelles and export out of the cell)

VacuolesWhat is it?- the storage area of the cell- a large storage sac, found mostly in plant cells (usually has one main vacuole)- smaller vacuoles can be found in some animal cells

What is it made of?- a membrane

What does it do?- serves as storage for plants- stores water, nutrients, wastes- helps control pressure/movement in the cell

Journal

November 21: research

November 27: research/slides

November 1: research/slides

December 2: slides

December 3: slides

December 4: slides/images

December 8: touch up/quiz

QuizChoose the best answer.

Which is a function of a cell?

A) making proteins

B) adapting to their environment

C) getting rid of wastes

D) all of the above

What’s the difference between plant cells and animal cells?

A) plant cells have cell walls

B) animal cells have centrioles

C) plant cells have vacuoles

D) both A and B

Which is a NOT a feauture of a prokaryotic cell?

A) has a simple structure

B) has no membrane-bound organelles

C) has a nucleus

D) has a cell wall

How are the functions of the plasma membrane and the cell wall different?

A) cell wall provides rigidity and a defined shape to the cell while cell membrane controls what enters/leaves the cell

B) only cell wall provides protection

C) only cell membrane provides support

D) none of the above

QuizWhat is the skeleton and muscles of the cell?

A) the endoplasmic reticulum

B) the cytoskeleton

C) the cell wall

D) eukaryotes

Which structure makes enzymes for the cell?

A) the rough endoplasmic reticulum

B) the smooth endoplasmic reticulum

C) the golgi apparatus

D) lysosomes

Which part of the nucleus is responsible for making ribosomes?

A) the nucleolus

B) the nuclear envelope

C) chromatin

D) none of the above, the endoplasmic reticulum makes ribosomes

What cylindrical structure helps in cell division?

A) the vacuole

B) plastids

C) ribosomes

D) centrioles

QuizWhat acts as a messenger for the nucleus?

A) DNA

B) chromatin

C) RNA

D) centrioles

What makes proteins for the cell?

A) the endoplasmic reticulum

B) ribosomes

C) RNA

D) the golgi apparatus

Where does digestion of food first take place in the cell?

A) mitochondria

B) peroxisomes

C) lysosomes

D) both A and C

Where does photosynthesis take place in the plant cell?

A) chromoplast

B) leucoplast

C) chloroplast

D) the cell membrane

QuizWhat has its own separate DNA in the cell?

A) mitochondria

B) chloroplast

C) prokaryote

D) both A and B

What serves as the cell’s storage area?

A) the golgi apparatus

B) vacuoles

C) microtubules

D) none of the above

What is an example of a multicellular organism?

A) a human

B) a tree

C) bacteria

D) both A and B

ResourcesMiller Levine. Prentice Hall Biology. Pearson Education, Inc. New Jersey 2002

Davidson, Michael W. “Introduction to Cell and Virus Structure.” [http://www.microscopy.fsu.edu/cells/index.html]

"Cell (biology)." Microsoft® Encarta® Online Encyclopedia 2002. [http://www.encarta.com ]

University of Arizona. “Cell Biology.” [http://www.biology.arizona.edu/cell_bio/cell_bio.html ]

Sullivan, James A. “Cells Alive!” [http://www.cellsalive.com ]

Andrew Radar Studios. “Cells and Cell Structure.” [http://www.biology4kids.com/files/cell_main.html ]

“ThinkQuest Internet Challenge Library.” ThinkQuest, Inc. [http://library.thinkquest.org ]

Purves, William K. Sadava, David Orians, Gordon H. Heller, Craig. “The Cell.” [http://www.thelifewire.com ]

Kimball, John W. “Kimball’s Biology Pages.”[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages ]

Krupp, Dave. “Lecture 16.” [http://imiloa.wcc.hawaii.edu/krupp/BIOL101/present/lcture16 ]

ResourcesKrempels, Dana M. “The Cell: Smallest Living Level of Organization.” [http://fig.cox.miami.edu/Faculty/Dana/105F00_4.html ]

Franklin Institute. “Parts of the Cell.”[http://sln.fi.edu/qa97/biology/biopoint4.html

MSPCA.” Squirrel.”[http://www.livingwithwildlife.org/wildlifehelp/ animals/squirrel.jp]

The Nobel Foundation. “The Nobel Prize in Physiology or Medicine 1999.” [http://www.nobel.se/medicine/educational/poster/1999]

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