biology cell structure and function
TRANSCRIPT
CELLS: STRUCTURE AND FUNCTIONChapter 7.1, 7.2 & 7.4
Discovery of the cell
• Robert Hooke – early microscope, thin layer of cork, “cells”
• Anton van Leeuwenhoek – observed pond water – small living world
• Schleiden – all plants are made of cells• Schwann – all animals are made of cells• Virchow – cells come from existing cells
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The cell theory1. All living things are composed of
cells.
2. Cells are the basic unit of structure and function in living things.
3. New cells are produced from existing cells.
Characteristics of all cells•Surrounded by cell membrane (plasma)
•Contain DNA – genetic material (blueprint)
•Contain cytoplasm
Examples of CellsAmoeba Proteus
Plant Stem
Red Blood Cell
Nerve Cell
Bacteria
Prokaryotic• No nucleus (nucleoid region)
• Few internal structures - have simple ribosomes
• Smaller & simpler than eukaroytic cells
• One-celled organisms
• Ex. Bacteria http://library.thinkquest.org/C004535/prokaryotic_cells.html
Prokaryotic Cells• Some use flagellum for locomotion
• threadlike structures protruding from cell surface Bacterial cell wall
Flagellin
Rotarymotor
Sheath
Eukaryotic•Have a membrane bound nucleus, control center that holds DNA (genetic material)
•Contain organelles surrounded by membranes (small organs)
•Most living organisms – lots of variety•Larger & more complex than prokaryotic cells
http://library.thinkquest.org/C004535/eukaryotic_cells.html
Diversity of Life
• Unicellular Organisms• 1 cell• Ex. Bacteria, Amoeba
• Multicellular Organisms• 2 or more cells• Ex. Plants & Animals
• Levels of Organization• Cells• Tissues• Organs• Organ Systems
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Plant Cells vs. Animal Cells• Plant Cells
• Chloroplasts• Large Central Vacuole
• Cell Wall
• Animal Cells• Lysosome• Centrioles
ORGANELLESStructure & Function
Cell Membrane / Plasma• Outer membrane of cell that controls movement in & out of the cell
• Double layer (Lipid Bilayer)
• AKA - Plasma Membrane• Selectively permeable boundary between the cell and the environment
• All cells have this!!http://library.thinkquest.org/12413/structures.html
Cell Membrane / Plasma
Nucleus• Directs cell activities• Separated from cytoplasm by nuclear membrane
• Contains genetic material - DNA
• Nuclear Membrane• Surrounds nucleus• Made of two layers• Openings allow material to
enter and leave nucleus
Chromosomes/Chromatin• In nucleus• Made of DNA & protein
• Contain instructions for traits & characteristics
• Contains instructions for making proteins
http://library.thinkquest.org/12413/structures.html
Nucleolus• Inside nucleus• Makes ribosomes which then leave the nucleus
http://library.thinkquest.org/12413/structures.html
Ribosomes• Each cell contains thousands
• Make proteins (site for protein synthesis)
• Found on Rough ER & floating throughout the cell
http://library.thinkquest.org/12413/structures.html
Endoplasmic Reticulum• A system of tubes & sacs
formed by membranes (an enclosed space)
• Moves materials around inside of the cell
• Smooth: lacks ribosomes• Lipid synthesis, drug
detoxifcation
• Rough type (pictured): ribosomes embedded in surface • Transports proteins to the Golgi
bodyhttp://library.thinkquest.org/12413/structures.html
Golgi Bodies• Protein “packaging plant”
• Modifies protein• Attach lipids & carbohydrates to the protein
http://library.thinkquest.org/12413/structures.html
Vesicles move from ER to Golgi
Mitochondria• Produces energy through chemical reactions – cellular respiration
• Converts glucose into ATP
• Cristae – inner membrane
• Matrix – inner membrane space
http://library.thinkquest.org/12413/structures.html
Lysosome• Digestive sac for proteins, fats, & carbohydrates
• Transports undigested material to cell membrane for removal
• Cell breaks down if lysosome explodes
http://library.thinkquest.org/12413/structures.html
Cytoskeleton
Actin
Microtubules
Intermediate filaments
Cytoskeleton• Network of protein fibers supporting cell shape and anchoring organelles• Microfilaments
• Actin • Cell movement• Support of cell
• Microtubules• Hollow tubes• Movement of organelles• Forms cilia, flagella, centrioles
Cell membrane
Endoplasmicreticulum
Microtubule
Microfilament
Ribosomes Michondrion
Centrioles
• Assemble microtubules during cell division
• Barrel shaped – pairs
• Found In animal cells (used during cell reproduction)
Cell Wall• Most commonly found in plant cells & bacteria
• Supports & protects cells
http://library.thinkquest.org/12413/structures.html
Chloroplast• Found in plant cells• Contains green chlorophyll
• Location where photosynthesis takes place in the cell
http://library.thinkquest.org/12413/structures.html
Vacuoles• Membrane-bound sacs for storage, digestion, and waste removal
• Contains water solution
• Help plants maintain shape- large central vacuolehttp://library.thinkquest.org/12413/structures.html
“Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
“Typical” Plant Cell
Prokaryotes Eukaryotes
Cell membraneRibosomesCell wall
NucleusEndoplasmic reticulumGolgi apparatusLysosomesVacuolesMitochondriaCytoskeleton
Animal Cells Plant Cells
LysosomesCentrioles
Cell membraneRibosomesNucleusEndoplasmic reticulumGolgi apparatusVacuolesMitochondriaCytoskeleton
Cell Wall
Chloroplasts
Section 7-2
Venn Diagrams
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