http://koning.ecsu.ctstateu.edu/cell/cell.html

4A: Students will…

compare and contrast prokaryotic andeukaryotic cells

Robert Hooke (1665)

▪ Used a compound microscope to look at thin slices of cork (oak tree bark – dead plant cells)

▪ Saw empty spaces that looked like rectangular rooms, so he called them “cells”

Matthias Schleidan (1838)

▪ First to recognize that all plants (and plant parts) are made of cells

Theodor Schwann (1839)▪ First to recognize all animals (and animal parts) are

made of cells▪ When he learned of Schleidan’s findings, Schwann

published the statement that ALL LIVING THINGSare made of cells

Rudolf Virchow (1855)▪ Proposed all living cells come from cells that already

exist▪ Until this, most people believed living things could

come from non-living matter (spontaneousgeneration)

All living things are composed of cells.

Cells are the basic units (smallest working units) of structure and function of all living things

All cells come from preexisting cells through cell division (mitosis).

Amoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

❖ A cell is the smallest unit that is capable of performing life functions

❖ Lowest level of LIVING organization

Surface Area to Volume Ratio

▪ Surface Area = the area covered by the cell membrane

▪ Volume = the space taken up on the inside

▪ The higher the ratio, the more efficiently substances move through the cell (like bringing nutrients in and moving wastes out)

▪ Movement over long distances is slow and hard

i.e. = smaller cells move materials faster and more efficiently

•Prokaryotic•Eukaryotic

Simplest type of cell

No membrane-bound organelles

One-celled organisms (unicellular); bacteria

Bacteria have a single circular chromosome floating in the center of the cell

http://library.thinkquest.org/C004535/prokaryotic_cells.html

Surrounded by cell membrane and cell wall

Contains ribosomesfloating in the cytoplasm to make proteins

http://library.thinkquest.org/C004535/prokaryotic_cells.html

Contain organelles surrounded by membranes Most living organisms (protists, fungi, plants, and

animals) Some are unicellular, but most are multicellular Most complex type of cell

Plant Animal

http://library.thinkquest.org/C004535/eukaryotic_cells.html

http://waynesword.palomar.edu/images/plant3.gif

Organelles

Found in everything BUT animal cells!

Made of cellulose (chains of glucose) – biomolecule?

Supports & protects cells

Composed of a double layer ofphospholipids and proteins

Also has some carbohydrates (for signaling)

Surrounds ALL cells

Keeps the insides & outside of the cell separate

Controls movement in and out of the cell (semi-permeable)

http://library.thinkquest.org/12413/structures.html

Outsideof cell

Insideof cell(cytoplasm)

Cellmembrane

Proteins

Proteinchannel Lipid bilayer

Gel-like mixture where the organelles are found (it is in ALL cells)

Cushions and protectscell organelles

Surrounds nucleusof eukaryotic cells

Openings (pores) allow material to enter and leavenucleus

Directs cell activities in eukaryotic cells (“control center”)

Contains geneticmaterial (DNA)

Found

▪ In nucleus of eukaryoticcells.

▪ Freely floating in the cytoplasm of prokaryoticcells

Made of DNA (biomolecule?)

Contain instructions for traits & characteristics

“Powerhouse” of the cell

Found in ALL eukaryotic cells

Produces energy (ATP) for the cell through cellularrespiration by breaking down lipids & carbohydrates

More active cells (ex: muscle cells) have more mitochondria

http://library.thinkquest.org/12413/structures.html

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Burns glucose to release energy (ATP)

Stores energy as ATP

“Power plant” of the cell

Mitochondria takes the energy from food and stores it in ATP (in the bond between the 2nd and 3rd phosphate)

The last phosphate group on ATP is broken off to release energy

This creates ADP

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Rough = covered in ribosomes

Transports proteins to the Golgi Body.

Has no surface ribosomes and is attached to the end of the rough ER

Makes steroids and ions, regulates calcium (muscle cells), & destroys toxins (liver)

Sends steroids, ions, and other materials to the Golgi Body to be USED in the cell

Makes protein

Each cell contains thousands.

Found in all cell types

Found on rough ER& also floating throughoutthe cytoplasm.

http://library.thinkquest.org/12413/structures.html

Found in eukaryotic cells

Modifies, sorts, &packages molecules from ER for storage OR transport out of the cell

Makes vesicles (packages) to distributematerials to other parts of the cellhttp://library.thinkquest.org/12413/structures.html

Digests unwanted materials and transports them to the cell membrane for removal.

Contains digestive enzymes to break down old cell parts

Cell breaks down if lysosomeexplodes (“suicide sac”)

Sac containing water that helps maintain the shape of the cell.

Stores water, food/nutrientsand wastes

http://library.thinkquest.org/12413/structures.html

Plant cells have a LARGE central vacuole▪ Needed to regulate

pressure

▪ Allows the plant to remain rigid (stiff)

▪ Without enough water, the plant will wilt (droop)

http://library.thinkquest.org/12413/structures.html

Vacuole

Found ONLY in plant cells

Produces a green pigment called chlorophyll

Site of photosynthesis, which uses the energyfrom sunlight to produce food (sugar) for the cell along with oxygen

Chloroplasts inside the cells

Cilia: tiny hair-like structures that line certain cells and provide locomotion

Flagella: a long appendage that whips around to provide locomotion

Homeostasis

▪ Cell Membrane

▪ Cytoplasm

▪ Nucleus

▪ Lysosome

▪ Vacuole

Energy Conversion

▪ Mitochondria

▪ Chloroplast

Transport

▪ Cell Membrane

▪ Endoplasmic Reticulum

▪ Golgi Body

Formation of new molecules

▪ Ribosomes

▪ Endoplasmic Reticulum

▪ Golgi Body

Animal Cells

▪ No cell wall

▪ Usually round shape

▪ Nucleus towards center

▪ Many smaller vacuoles

▪ No chloroplasts

Plant cells

▪ Cell wall

▪ Usually rectangular

▪ Nucleus near cell wall

▪ Large central vacuole

▪ Chloroplasts

ALL cells (prokaryote AND eukaryote) have “DR.CC” cell membrane, cytoplasm, ribosomes, & DNA

Prokaryotes are simpler, unicellular, and have NO membrane-bound organelles

Bacteria are prokaryotes

Eukaryotes are usually multi-cellular (not always), more complex, and have membrane-bound organelles

Animals, Plants, Fungi, and Protists are all eukaryotes

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How can you tell?

Is this a plant cell or animal cell?

42

Contains organelles; a large vacuole, a cell wall and chloroplasts!

Chloroplast

Vacuole

Cell Wall

43

How can you tell?

Is this a Prokaryotic or Eukaryotic cell?

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Contains organelles; a central nucleus, and no cell wall or chloroplasts!