Structure and Function

Section 7-1

 Prokaryotes  Eukaryotes

 Robert Hooke Observed a piece of cork with a compound microscope Saw thousands of empty chambers  Called these chambers “Cells”  Anton van Leeuwenhoek Used a single lens microscope to look at pond water Revealed thousands of tiny living organisms

ROBERT HOOKE’S “CELLS” LEEUWENHOEK’S “ORGANISMS”

 Matthias Schleiden All plants are made of cells  Theodore Schwann All animals are made of cells  Rudolph Virchow Cells arise from other cells

 All living things are composed of cells  Cells are the basic units of structure and functions in living things  New cells are produced from preexisting cells

 Most basic unit of life  Varying sizes (.2 μ m μ m)  2 Common Characteristics Surrounded by a Cell Membrane Contains DNA  2 Types Prokaryotes Eukaryotes

 Bacteria & Archea  Pro- “Before” Karyon- “Nucleus”  Genetic information is NOT contained in nucleus Condensed in an area called the “nucleoid”  Smaller and more simplistic.

 Eu- “True”  Karyon- “Nucleus”  Genetic information is stored in the nucleus  Contains membrane bound organelles  Larger and more complex  Plants, animals, fungi, and protists

 Confocal Light Microscopy Scans cell with laser beam and builds a 3D model of cells and parts Has its limits, light is diffracted as it passes through matter, limits the resolution of image. Almost impossible to see proteins or viruses

 Transmission Electron Microscopes Beams of electrons are shot through a thin slice of a specimen Allows detailed structures of small proteins to be seen  Scanning Electron Microscopes Beam of electrons passes across specimen Forms a highly detailed 3D image of the specimen Must be done in a vacuum to work properly

 Has a resolution 1000X that of light microscopes Wavelengths of electrons are much shorter than light  2 Types: Transmission Electron Microscope Scanning Electron Microscope

 Scanning Probe Microscope Traces surface of specimen with a probe So powerful it has observed a single atom Can operate in ordinary air (no special conditions needed) Used to image DNA and protein molecules

Section 7-2

 Highly complex  Organelles Specialized structures within the cell  Divides Cell into 2 Sections Nucleus Cytoplasm

 Portion of the cell outside the nucleus  Houses most organelles

 Control Center of the cell  Contains almost all the cell’s DNA Coded with instructions for forming proteins and other important molecules

 Covers nucleus  Filled with pores  Regulates flow of material in and out of the nucleus RNA, Proteins, etc.

 Chromatin DNA bound to protein; normally spread throughout nucleus  Chromosomes Condensed chromatin that appears during cell division Carrier for genetic information through generations

 Dense center of nucleus Where ribosome assembly begins

 Small particles of RNA and protein found in cytoplasm Produce proteins based on coded information from nucleus

 Site where lipid components of cell membrane and protein assembly occur  Smooth ER Lipid synthesis  Rough ER Coated with Ribosomes Involved with protein assembly

 Modifies, sorts, and packages proteins and other materials from the ER for storage or secretion outside cell

 Small organelles filled with enzymes  2 functions Digestion of proteins, lipids, and carbohydrates for reuse Breaking down organelles that begun to shut down

 Storage structures that hold water, salts, proteins, and carbohydrates for future use  Can be used in some simple cells as a pump to remove excess water

 Convert the chemical energy stored in food into compounds that are more convenient for the cell’s use  Double membrane Inner membrane is folded inside organelle

 Capture energy from the sunlight and convert it into chemical energy via photosynthesis  Contains chlorophyll Makes the structure green

 Network of protein filaments that helps the cell maintain its shape and deals with movement

 Mircofilaments Made of actin; creates flexible framework for cell  Microtubules Hollow tubes made of tubulins, forms spindle fibers during cell division  Centrioles Organize cell division; only in animal cells

 Lacks a rigid cell wall  Smaller Vacuole  Contains Centrioles Used during Cell Division

 Has a rigid cell wall  Contains a very large vacuole  Chloroplasts Contains photosynthetic pigments

Section 7-3