Post on 12-Jan-2016
All organisms are composed of cells Cells are the smallest living unit of living things All cells come from cells
The Cell Theory
Spontaneousgeneration
Cell theory Germ theory of disease Theory of evolution Atomic theory Heliocentric theory of the solar system Universal gravitation Theory of relativity Quantum theory String theory
Important Scientific Theories
Prokaryotes
Eukaryotes
What kinds of organisms are
they?
What are the characteristics of their cells?
The Prokaryotic Cell
Cell membrane (plasma membrane)• Boundary• Semi-permeable
The Prokaryotic Cell
Ribosomes• Not membrane-bounded• Protein synthesis
The Prokaryotic Cell
Cell wall • Rigid• Permeable
Nucleoid• Genetic material (DNA)
The Prokaryotic Cell
Flagella• Protein filaments• Motility
The Prokaryotic Cell
The Eukaryotic Cell
Ribosomes• Bound to ER (rER) – secreted proteins• Free – cytosol proteins
The Eukaryotic CellNucleus• Genetic material (DNA)• Chromatin (chromosomes)• Nuclear envelope (with pores)• Nucleolus
The Eukaryotic Cell
Mitochondria• Energy transduction• Aerobic respiration → ATP• 2 membranes• Own DNA (16,000 bp) & ribosomes• Reproduce independently by division
outermembrane
innermembrane
inter-membranespace
matrix
The Eukaryotic Cell
Chloroplasts• Energy transformation: photosynthesis• Photosynthetic eukaryotes only• 3 membranes• Own DNA & ribosomes• Reproduce independently by division
The Eukaryotic Cell
Endoplasmic reticulum• rough: synthesis of secreted proteins• smooth: lipid synthesis
sER
rER
vesicle
The Eukaryotic Cell
Golgi apparatus• Modification of secreted proteins• Distribution of secreted proteins
Vesicle• Transport of secreted proteins
The Eukaryotic Cell
Lysosomes• Small membrane sacs• “Recycling center”• Enzymes break down molecules
The Eukaryotic Cell
Vacuole• Storage• Phagocytosis• Water balance• etc.
The Eukaryotic CellCytoplasm• Everything outside the nucleus• Includes organelles
Cytosol• Gel-like fluid of cytoplasm• Does not include organelles•Proteins, amino acids, nucleotides, salts, small molecules…
Cytoskeleton• Networks of protein fibers•Structure, motility, organization, transport…
Similar in size to prokaryotic cells Two membranes Own DNA Own ribosomes, prokaryote-like Divide independently DNA sequence like prokaryotic genes
The Endosymbiosis Theory ancestral cell
membrane infoldingcreates nucleus, ER
endosymbiosisresults in mitochondria
ancestralanimal cell
ancestralplant cell
endosymbiosisresults in chloroplasts
Why are prokaryotes small and eukaryotes large?