Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Extracellular matrix wikipedia , lookup
Cytokinesis wikipedia , lookup
Cell growth wikipedia , lookup
Tissue engineering wikipedia , lookup
Endomembrane system wikipedia , lookup
Cell culture wikipedia , lookup
Cellular differentiation wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cell encapsulation wikipedia , lookup
Chapter 4 – A Tour of the Cell Intro The Microscopic World of Cells • Organisms are either: – Single-celled, such as most bacteria and protists – Multicelled, such as plants, animals, and most fungi Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings Life’s 3 Domains Scientist’s study of different organisms’ cell structure and DNA lead them to group organisms into 3 different domains Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings Life’s 3 Domains Plants Animals Fungi Eubacteria: common bacteria First Eukaryotes -- Protists Archaebacteria: Oldest bacteria First cells (prokaryotic) 3.5 billion years ago Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings My Thoughts (Complete one of the following statements on the left side opposite the notes you just took) I can picture… A question I have is… This is like… This reminds me of… I am confused about… The big idea here is… I think/wonder…. I predict that… Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings The Microscopic World of Cells • The human body is made up of trillions of cells many of which are specialized – Muscle cells, Nerve cells, & blood cells… Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings The Cell Theory • Cells were first discovered in 1665 by Robert Hooke. • The accumulation of scientific evidence led to the cell theory - All living things are composed of one or more cells - All cells are formed from previously existing cells Cell theory 6 minute video: http://ed.ted.com/lessons/the-wackyhistory-of-cell-theory Microscopes provide windows to the world of the cell The Light Microscope Light passes through the specimen Lenses enlarge, or magnify, the image Magnification – the increase in the specimen’s apparent size Resolving power – the ability to show 2 objects as being separate Microscopes provide windows to the world of the cell The Electron Microscope Uses a beam of electrons Resolving power is higher than the light microscope Can magnify up to 100,000X The Size of Cells Most cells are 10-100 micrometers (µm) in size Cell size and shape are related to their function Ex: red blood cells, nerve cells, eggs The Size of Cells 30 µm 10 µm • The lower limit of cell size is determined by the fact that a cell must be large enough to house the parts (DNA, organelles) it needs to survive and reproduce. • The maximum size of a cell is limited by the amount of surface needed to obtain nutrients from the environment and dispose of wastes. The Two Major Categories of Cells The Two Major Categories of Cells • There are 2 major categories of cells - Prokaryotic cells - Eukaryotic cells • Both cells - Are surrounded by a plasma membrane - Consist of cytoplasm and organelles and contain DNA • Prokaryotic and eukaryotic cells differ in several ways Comparing Eukaryotic and Prokaryotic CellsProkaryotes Eukaryotes Differences Differences Commonalities Prokaryotic Cells • Smaller than eukaryotic cells • • • • • (2-8 um) Enclosed by a plasma membrane that is usually surrounded by a rigid cell wall The cell wall may be covered by a sticky capsule DNA is found inside the cell but it is not housed in a nucleus Ribosomes (70S) are present Internal structures surrounded by membranes are not present Eukaryotic Cells Larger than prokaryotic cells (10-100 um) More complex in structure DNA housed in the nucleus Ribosomes (80S) Membrane bound organelles Comparing Animal and Plant Cells Animal cells contain centrioles, lysosomes, flagella Plant cells contain a central vacuole, cell wall, chloroplasts Comparing Eukaryotic and Prokaryotic CellsProkaryotes Eukaryotes Differences Differences Commonalities Comparing Eukaryotic and Prokaryotic Cells- Differences in parallel Eukaryotic Cells statements Prokaryotic Cells Descended from ancient prokaryotes Date back at least 3.5 BYA 2.1 BYA Ex include: Bacteria & Ex organisms: plants, animals, fungi, Archaeabacteria protists Simpler Structure (all single celled More Complex Structure (mostly organisms) multicellular organisms but some single Naked DNA (not wrapped around histone celled organism) proteins) DNA associated with histone proteins Circular Chromosomes DNA in cytoplasm (nucleoid region) 70S ribosomes No internal membrane compartments (no membrane bound organelles)-ex: no mitochondria, no Rough ER Chromosomes linear DNA separated from cytoplasm (in nucleus) 80S ribosomes Internal membrane compartments (membrane bound organelles) –ex: yup mitochondria and Rough ER Comparing Eukaryotic and Prokaryotic CellsCommonalities: Prokaryotes & Eukaryotes Smallest units of Life (therefore has the characteristics of life Chapter 1!) Requires energy (to run metabolic reactions of life) Grows and develops Independently reproduce DNA stores genetic information Can evolve over generations Order: internal organization Responds to environmental stimuli Ribosomes build proteins for the cells Contains plasma membrane to regulate what enters and leaves the cell Filled with cytosol (fluid)