CELL HISTORY

• Main Characteristics of organisms

  • Made of CELLS
  • Require ENERGY (food)
  • REPRODUCE (species)
  • Maintain HOMEOSTASIS
  • ORGANIZED
  • RESPOND to environment
  • GROW and DEVELOP
  • EXCHANGE materials with surroundings (water, wastes, gases)
• Nonliving Levels of Organization

  • ATOM (element)
  • MOLECULE (compounds like carbohydrates & proteins)
  • ORGANELLES (nucleus, ER, Golgi …)
• Living Levels of Organization

  • CELL (makes up ALL organisms)
  • TISSUE (cells working together)
  • ORGAN (heart, brain, stomach …)
  • ORGAN SYSTEMS (respiratory, circulatory …)
  • ORGANISM
  • POPULATION (one species in an area)
  • COMMUNITY (several populations in an area)
  • ECOSYSTEM (forest, prairie …)
  • BIOME (Tundra, Tropical Rain forest…)
  • BIOSPHERE (all living and nonliving things on Earth)
• Robert Hooke


  1665, he used a microscope to examine a thin slice of cork (dead plant cell walls) and saw what looked like small boxes, which he called "cells"
• Anton van Leeuwenhoek


  Used his microscope in studying plant and animal cells, was the first to see red blood cells and name tiny microorganisms as "animalcules"
• Robert Brown


  Discovered the nuclei acid within the cells
• Felix Dujardin


  Credited for describing a formless substance in microorganisms which he called sarcode
• Matthias Schleiden


  1838, concluded that all plants were made of cells, co-founder of the cell theory
• Theodore Schwann


  1839, concluded that all animals were made of cells, co-founder of the cell theory
• Rudolph Virchow


  1855, observed cells dividing under the microscope and reasoned that all cells come from other pre-existing cells by cell division
• Cell Theory


  • All living things are made of cells
  • Cells are the basic unit of structure and function in an organism (basic unit of life)
  • Cells come from the reproduction of existing cells (cell division)
• Basic Types of Cells

  • Animal Cell
  • Plant Cell
  • Bacterial Cell
• Cell Size


  Typical cells range from 5 – 50 micrometers (microns) in diameter
• Organisms based on Number of Cells

  • Unicellular – composed of one cell
  • Multicellular- composed of many cells that may organize into tissues, etc.
• Cell Type Size


  Plant cell > Animal cell > Bacteria
• Cell Specialization


  Cells in a multi-cellular organism become specialized by turning different genes on and off, known as DIFFERENTIATION
• Specialized Animal Cells


  • Muscle cells
  • Red blood cells
  • Cheek cells
• Prokaryotes


  Cells that lack a nucleus or membrane-bound organelles, includes bacteria, simplest type of cell with a single, circular chromosome
• Prokaryotes

  • Nucleoid region (center) contains the DNA, surrounded by cell membrane & cell wall (peptidoglycan), contain ribosomes (no membrane) in their cytoplasm to make proteins
• Eukaryotes


  Cells that HAVE a nucleus and membrane-bound organelles, includes protists, fungi, plants, and animals, more complex type of cells
• Eukaryotic Cell Basic Structures

  • Nucleus
  • Cell Membrane
  • Cytoplasm with organelles
• Two Main Types of Eukaryotic Cells

  • Plant Cell
  • Animal Cell
• Animal Cell Organelles


  • Nucleolus
  • Nucleus
  • Nuclear envelope
  • Ribosome (attached)
  • Ribosome (free)
  • Cell Membrane
  • Rough endoplasmic reticulum
  • Golgi apparatus
  • Mitochondrion
  • Smooth endoplasmic reticulum
  • Centrioles
• Plant Cell Organelles


  • Cell or Plasma Membrane
  • Cell Wall
  • Cytoplasm
  • Nucleus
  • Mitochondrion
  • Chloroplast
• Cell Membrane


  It is the outer boundary of the cell that separates its contents from its external environment, controls the movement of materials in and out of the cell
• Cell Membrane

  • Molecules in cell membranes are constantly moving and changing, making it fluid
• Cell Membrane in Plants

  Lies immediately against the cell wall, pushes out against the cell wall to maintain cell shape
• Cell Wall


  Nonliving layer found in plants, fungi, & bacteria, made of cellulose in plants, peptidoglycan in bacteria, and chitin in Fungi, supports and protects the cell
• Cytoplasm


  Jelly-like substance enclosed by cell membrane, provides a medium for chemical reactions to take place
• Nucleus


  Controls the normal activities of the cell, contains the DNA in chromosomes, bounded by a nuclear envelope (membrane) with pores, usually the largest organelle
• Nucleus


  • Each cell has a fixed number of chromosomes that carry genes, genes control cell characteristics
• Chromatin and Chromosomes


  DNA is spread out as chromatin in non-dividing cells, DNA is condensed & wrapped around proteins forming chromosomes in dividing cells
• Cytoskeleton


  Helps cell maintain cell shape, also helps move organelles around, made of proteins including microfilaments (actin) and microtubules (tubulin)
• Centrioles


  Found only in animal cells, paired structures near nucleus, made of bundle of microtubules, appear during cell division forming mitotic spindle, help to pull chromosome pairs apart
• Mitochondrion


  "Powerhouse" of the cell, generate cellular energy (ATP), more active cells like muscle cells have MORE mitochondria, both plants & animal cells have mitochondria, site of CELLULAR RESPIRATION (burning glucose)
• Types of Endoplasmic Reticulum (ER)


  • Rough ER - has ribosomes on its surface, makes membrane proteins and proteins for export out of cell
  • Smooth ER - lacks ribosomes, attached to ends of rough ER, makes cell products used inside the cell
• Endomembrane System


  Includes nuclear membrane connected to ER connected to cell membrane (transport)
• Ribosomes


  "Protein factories" for cell, join amino acids to make proteins, process called protein synthesis, can be attached to Rough ER or free (unattached) in the cytoplasm
• Golgi Bodies


  Stacks of flattened sacs, have a shipping side (trans face) and receiving side (cis face), receive proteins made by ER, transport vesicles with modified proteins pinch off the ends
• Golgi Bodies


  • Modify, sort, & package molecules from ER for storage OR transport out of cell