Transcript H. Bio Cells

Chapter 4A View of the Cell
4.1-The Discovery of Cells
 Cells are the basic units of living
organisms
 Development of the microscope allowed
scientists to view cells
Cell Theory
 1665-Robert Hooke
 Uses compound microscope to observe
cork
 Hollow boxes…..CELLS!!
 1830s-Schleiden and Schwann
 Schleiden-all plants are composed of
cells!
 Schwann-all animals are composed of
cells!
Three Parts of Cell Theory
 1. All organisms composed of one or more
cells.
 2. Cell is the basic unit of organization of
organisms.
 3. All cells come from preexisting cells.
History of the Microscope
 1665-Hooke’s Microscope
 Three lenses
 Poor Quality
 Little detail
 1700-Anton van Leeuwenhoek
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Built over 240 microscopes!
Single Lens
Better Quality
Observed red blood cells & bacteria
 Mid 1800s-Compound Light Microscope
 Series of lenses
 Light passes through object then lens
 More detail
 1940s-Electron Microscopes
 Beam of electrons through magnetic field
 Specimen in vacuum
 Only view dead cells or organisms
 1.SEM-Scanning Electron Microscope
 Surface of specimen-3D Picture!
 2.TEM-Transmission Electron Microscope
 Through the specimen
 Magnify 100s or 1,000s of times!
 3.STM-Scanning Tunneling Microscope
 Arrangement of atoms on surface
 Map hills and valleys
Basic Cell Types…
 Look at internal organization!
 Prokaryotes-lacks internal structures
 Eukaryotes-membrane bound,
internal structures.
 Structures called organelles
 Largest organelle = NUCLEUS!
Section 4.2-Eukaryotic Cell
Structure
 Must have boundaries!
 Plasma Membrane
 Boundary between cell & environment
 Flexibility
 Controls movement of materials
 Cell Wall-only plant cells!
 Rigid, surrounds membrane
 Thicker, stronger network for structural
support
Fluid-Mosaic Membrane
GET UNDER CONTROL!!!!
 Nucleus-contains cell’s DNA, manages
cell function
 Surrounded by nuclear envelope
 Double membrane-pores allow movement
 Chromatin-long strands of DNA
 Packed into chromosomes
Nucleus
 Nucleolus
 Region inside nucleus
 Produces particles for protein synthesis
 Particles are called ribosomes
 Cell assembles enzymes according to
DNA
 Not bound by membrane
Nucleolus
Assembly, Transport, &
Storage
 Cytoplasm-outside nucleus, surrounds
organelles
 Clear liquid
 Important chemical reactions (protein
assembly) take place here
 Endoplasmic Reticulum (ER) Network of interconnected compartments
 Surface folded into cell
 Tissues in a box!
 Site for lipid synthesis in cell
Smooth or Rough?
 Smooth ER
 Lacks ribosomes on surface
 Rough ER
 Studded with ribosomes on surface
 ER acts as cell’s delivery system!
Structures for Storage
 Golgi Apparatus
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Closely stacked, flattened membrane sacs
Receives proteins and lipids
Modifies them chemically, repackages
Distributes them throughout membrane
 Vacuole-sac of fluid
 Temporary storage of food, enzymes etc.
 Animal cell-small and numerous
 Plant cell-single large vacuole for water
Golgi
Apparatus
Vacuole
Reduce, Reuse, RECYCLE!
 Lysosomes
 Digest excess or worn out cell parts,
food particles, and invading
viruses/bacteria
 Membrane protects digestive enzymes
from rest of cell
Energy Transformers
 Mitochondria
 Break down food-convert to energy!
 Peanut-shaped
 Highly folded inner membrane for more
energy storage
 Chloroplasts-plants only!
 Transform light energy into chemical energy
 Chlorophyll-traps energy from sun
 Green color!
NRG!!
Support and Locomotion
 Cytoplasm
 1. Cytoskeleton-network of fibrous elements
 Act as scaffold for organelle support
 2. Microtubules-thin, hollow cylinders
 Made of protein
 3. Microfilaments-thin, solid fibers
 Both make up most of cytoskeleton
LET’S GET MOVING!
 Cilia
 Short, numerous hair-like projections
 On cell’s surface
 Movement like “the wave!”
 Flagella
 Longer projections
 Whip-like motion
 One or two per cell
Flagella vs Cilia
Cellular Organization
 1. Single-celled organisms:
Unicellular
 2. Many-celled organisms:
Multicellular
 3. Cells functioning together for
activity: Tissues
 4. Two or more tissues functioning
together: Organs
 5. Organs working together to carry
out major life functions:Organ System