Cells: Prokaryotic vs Eukaryotic Cell movie – 17:20 mins w/questions

Discovery of Cells Robert Hooke (mid-1600s) Observed sliver of cork Saw “row of empty boxes” = CELLS Referring back to the cells or “pores” of once-living trees

Definition of Cell A cell is the smallest unit that is capable of performing life functions. Smallest living unit ; most are microscopic

Cell theory (1839)Theodor Schwann & Matthias Schleiden “ all living things are made of cells” (50 yrs. later) Rudolf Virchow “all cells come from cells” via cell division

Cell Theory Smallest living unit of structure and function of all organisms is the cell All living things are made of cells All cells arise from preexisting cells (this principle discarded the idea of spontaneous generation)

Spontaneous Generation Living organisms could arise directly and rapidly from nonliving material Ex: Maggots from rotting meat Discredited as of the mid-19th century http://www.youtube.com/watch?v=WNB yRghR6sw

Characteristics of All Cells A surrounding membrane  plasma or cell membrane Protoplasm/Cytoplasm – cell contents in thick fluid Organelles – structures for cell function Control center with DNA

Examples of Cells Plant Stem Bacteria Red Blood Cell Nerve Cell

Cells have evolved two different architectures: Prokaryote “style”  NO NUCLEUS Eukaryote “style”  NUCLEUS

tallest trees adult human chicken egg frog embryo most eukaryotic cells Figure: 04-01 Title: Relative sizes. Caption: Dimensions commonly encountered in biology range from about 100 meters (the height of the tallest redwoods) through a few micrometers (the diameter of most cells) to a few nanometers (the diameter of many large molecules). mitochondrion most bacteria virus proteins diameter of DNA double helix atoms

PROKARYOTIC CELLS:

Prokaryotic First cell type on earth, smallest Do not have structures surrounded by membranes Few internal structures One-celled organisms, Bacteria http://library.thinkquest.org/C004535/prokaryotic_cells.html

These are prokaryote E. coli bacteria on the head of a steel pin.

Prokaryote cells are simply built (example: E. coli) capsule: slimy outer coating cell wall: tougher middle layer cell membrane: delicate inner skin

Prokaryote cells are simply built (example: E. coli) cytoplasm: inner liquid filling DNA in one big loop (not in a nucleus)  “nucleoid” pilli: for sticking to things flagella: for swimming ribosomes: for building proteins Nucleoid region of DNA concentration Proteins made from ribosomes  used as enzymes or as support for other cell functions ; need to be made to complete various cellular processs - Costruction guys who connect 1 amino aci at a time and build long chains Cytoplasm – referring to the protoplasm – that liquid of “jelly” – jell-o Flagella  motility

Prokaryote lifestyle unicellular: all alone colony: forms a grouping filamentous: forms a chain of cells

*label prokaryotic cell (bacterial cell)

Prokaryote Feeding Photosynthetic: energy from sunlight Disease-causing: feed on living things Decomposers: feed on dead things Disease-causing: example ecoli or salmonella

Eukaryotic cells:

Eukaryotic Contain organelles surrounded by membranes Most living organisms Animal Plant http://library.thinkquest.org/C004535/eukaryotic_cells.html

Eukaryotes are bigger and more complicated Have nucleus Have organelles Have chromosomes can be multicellular include animal and plant cells

Organelles are membrane-bound cell parts Mini “organs” that have unique structures and functions Located in cytoplasm Cytoplasm  liquid – the jell-o of the cell

Cell Structures Cell membrane Outer membrane that controls movement into and out of cell

Nucleus Control center of the cell – stores chromosomes (DNA) Contains nucleolus – produces ribosomes

Nucleolus inside nucleus Contains RNA to build proteins

the more energy the cell needs, the more mitochondria it has Mitochondrion Provides/releases energy that powers cellular activities *cellular respiration the more energy the cell needs, the more mitochondria it has Produces energy through chemical reactions – breaking down fats & carbohydrates Controls level of water and other materials in cell Recycles and decomposes proteins, fats, and carbohydrates

Each cell contains thousands Synthesize proteins Ribosomes Each cell contains thousands Synthesize proteins may be free- floating or attached to ER Each cell contains thousands Make proteins Found on ribosomes & floating throughout the cell Made of RNA

Cytoskeleton found throughout cytoplasm 3 functions: mechanical support anchor organelles help move substances Within cytoplasm – acts as both a muscle and a skeleton ; for movement and stability

Endoplasmic reticulum Folded membranes attached to nucleus may be smooth: lacking ________ may be rough: has attached _____________ Smooth  “storage organelle” ;

Ribosomes embedded on Rough endoplasmic reticulum

Rough Endoplasmic Reticulum Ribosomes attached to surface Important in synthesis and packaging of proteins Rough Endoplasmic Reticulum

Smooth Endoplasmic Reticulum No attached ribosomes Known as a “storage site” Has enzymes that help build molecules Carbohydrates Lipids Storage site for steriods and ions that the body may need later on

takes in sacs of raw material from ER Golgi Apparatus takes in sacs of raw material from ER sends out sacs containing finished cell products “packing and shipping” station Protein 'packaging and shipping station’ Move materials within the cell Move materials out of the cell

Golgi Apparatus Function 1. Molecules come in vesicles 2. Vesicles fuse with Golgi membrane 3. Molecules may be modified by Golgi

Golgi Apparatus Function (Continued) 4. Molecules pinched-off in separate vesicle 5. Vesicle leaves Golgi apparatus 6. Vesicles may combine with plasma membrane to secrete contents

sacs filled with digestive enzymes Lysosomes sacs filled with digestive enzymes digest worn out cell parts digest food absorbed by cell If explodes, cell breaks down! Digestive 'plant' for proteins, fats, and carbohydrates Transports undigested material to cell membrane for removal Cell breaks down if lysosome explodes

Centrioles pair of bundled tubes Plays a role in cell division

Cytoplasm “jell” or fluid in which organelles are found Site where chemical reactions occur within a cell

Structures found ONLY in PLANT cells Cell wall Tough, flexible, fairly rigid outer layer (chain link fence) protects cell from rupturing

(central) Vacuole Membrane- bound storage sac Holds water, food, waste items Helps plants maintain shape

Chloroplasts filled with chlorophyll turn light energy into food energy (photosynthesis

How are plant and animal cells different?

How are plant and animal cells different? How are plant and animal cells similar? Differences  Plants have…cell wall, chloroplasts, vacuole Similarities  Both eukaryotic, surrounded by cell membrane

Structure Animal cells Plant cells cell membrane Nucleus Nucleolus Nucleoid ER Golgi Capsule cell wall Mitochondria Cholorplasts One big vacuole Cytoskeleton Cytoplasm -- both Golgi apparatus – both

Structure Animal cells Plant cells cell membrane Yes yes nucleus nucleolus ribosomes ER Golgi centrioles no cell wall mitochondria choloroplasts One big vacuole No, but has sm.vacuoles cytoskeleton

Structure Animal cells Plant cells Lysosome Yes (more common) Yes (some) Cilia/flagella Yes No Cytoplasm Nucleoid

Structure Animal cells Plant cells Lysosome Cilia/flagella Cytoplasm Ribosomes Pilli

Eukaryote cells can be multicellular The whole cell can be specialized for one job cells can work together as tissues Tissues can work together as organs

Advantages of each kind of cell architecture Prokaryotes Eukaryotes simple and easy to grow can specialize fast reproduction multicellularity all the same can build large bodies

Examples of specialized euk. cells liver cell: specialized to detoxify blood and store glucose as glycogen.

sperm cell: specialized to deliver DNA to egg cell

Mesophyll cell specialized to capture as much light as possible inside a leaf

How do animal cells move? Some can crawl with pseudopods Some can swim with a flagellum Some can swim very fast with cilia

Pseudopods means “fake feet” extensions of cell membrane example: ameoba

Flagellum/flagella large whiplike tail pushes or pulls cell through water can be single, or a pair

Cilia fine, hairlike extensions attached to cell membrane beat in unison

Brief look at Viruses… Infectious particle (genes packaged within a protein coat) NOT considered living (cannot reproduce or carry out metabolism outside of host cell) Cause serious diseases in most organisms

Cell Integration Interaction of nucleus- ribosome Nucleus is the control center of the cell-You already know this much Now, what does it control? It controls the chemical reactions that occur in the cell This is done by controlling what enzymes are made at what time