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• Plasma membrane ◦ Surrounds and protects cell ◦ Separates cell from environment DNA ◦ Codes genetic instructions Organelles ◦ Internal structures for special functions Prokaryotic cells ◦ Bacteria and archaea ◦ Single celled organisms ◦ No membrane-bound organelles Eukaryotic cells ◦ Organelles enclosed by membranes ◦ Nucleus contains DNA ◦ May be unicellular or multicellular Unicellar, eukaryotic cell Prokaryotic cell Salmonella bacteria showing its peritrichous flagella used in locomotion. TEM X13,250. DNA and RNA Transmits information from one generation to the next Contains 4 types of nucleotides Makes up genes Codes for proteins Genetic code is virtually universal. Asexual reproduction Sexual reproduction ◦ Low genetic variability ◦ Example: Binary fission ◦ High genetic variability ◦ Fusion of egg and sperm cell to produce a fertilized egg DNA and RNA direct the development of new organism Most plants and animals reproduce sexually The Unifying Concept of Biology Theory of Evolution ◦ Explains changes in populations over time Evolution ◦ Processes by which populations change over time ◦ Energy from the sun is used to take up carbon dioxide from the environment and convert it into fuel molecules Organisms extract energy from fuel molecules which is used to make ATP Processes of glycolysis, aerobic respiration Producers (autotrophs) ◦ Make their own food ◦ Transform light energy to chemical energy through photosynthesis ◦ Example? Consumers (heterotrophs) ◦ Use energy stored by producers through cellular respiration ◦ Example? Decomposers (heterotrophs) ◦ Break down wastes and dead organisms ◦ Example? •Is hierarchical •Includes chemical, cell, tissue, organ, organ system, and organism levels •Includes population, community, ecosystem, and biosphere levels Organism Population Organ system Organ Tissue Community Bone cells Cell Nucleus Organelle Ecosystem Macromolecule Molecule Biosphere Oxygen atom Hydrogen atoms Water Fig. 1-6, p. 7 Figure 1.6 From Molecules to the Biosphere: The Hierarchy of Life (Part 1) Atom Atoms make up molecules. Molecules are organized into cells Neuron Ganglion Ecosystem Binomial system Taxonomy is science of naming and classifying organisms Classification used to be based on physical similarities, now based on genetic relatedness Biologists use a binomial system for classifying organisms ◦ ◦ ◦ ◦ Linnaeus developed the system of classification used today Binomial nomenclature describes the genus and species of the organism Each species is identified by two names Rana pipiens North leopard frog Rana sylvatica wood frog Genus name (capitalized) followed by species name (not capitalized). Both names should be underlined or italicized. Domain Kingdom Phylum Class Order Family Genus Species DOMAIN Eukarya KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER Primates FAMILY Pongidae GENUS Pan SPECIES Pan troglodytes Stepped Art Fig. 1-8, p. 10 DOMAIN Eukarya HUMAN?? KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER Primates FAMILY Pongidae GENUS Pan SPECIES Pan troglodytes Stepped Art Fig. 1-8, p. 10 The tree of life includes three major branches, or domains, and six kingdoms • Three Domains: Bacteria Archaea Eukarya Six Kingdoms: Bacteria Archaea Protista Plantae Animalia Fungi Common ancestor of all organisms Fig. 1-9, p. 12 Bacteria Archaea Eukarya Bacteria and Archaea cells are prokaryotic Eukarya cells are eukaryotic Bacterial cells are prokaryotes ◦ Pro-before ◦ karyon-nucleus Lack a membrane-bound nucleus Have a nuclear region called “nucleoid” which contains the hereditary material, DNA Less complex than eukaryotic cells Eu-good Karyon-nucleus Genetic material found in a membraneenclosed compartment called the nucleus ◦ Prokaryotic ◦ One kingdom in Archaea called Archaea Prokaryotic One kingdom in domain called Bacteria (or Eubacteria) Protista Plantae Fungi Animalia ◦ ◦ ◦ ◦ ◦ ◦ Kingdom Bacteria consists of bacteria Kingdom Archaea unique group of prokaryotic organisms, which biologists recently have split off from the bacterial kingdom (Bacteria) Kingdom Protista protozoans and algae (now called microbial protists) Kingdom Fungi mushrooms, molds, and yeasts Kingdom Plantae plants Kingdom Animalia animals Activity 26.1: Classification schemes Plants are multicellular autotrophs ◦ Use light energy to make fuel molecules Fungi are heterotrophs with absorptive nutrition ◦ Most are multicellular (yeasts are unicellular) ◦ Molds, mushrooms, yeasts ◦ Fungi break down food molecules in their environment and then absorb breakdown products into their cells ◦ Fungi are important decomposers of dead materials of other organisms Animals are multicellular heterotrophs that obtain food by ingestion. Ingest food, digest the food outside their cells, absorb breakdown products into their cells Microbial protists can be either heterotrophic or autotrophic Unicellular ◦ Few multicellular exceptions exist Very diverse group of organisms Compare: Autotrophic/heterotrophic Multicellular/unicellular Eukaryotic/prokaryotic Ingestive nutrition/absorptive nutrition (heterotrophs) Eukaryotic Mostly multicellular Obtain food by ingestion Eukaryotic Mostly multicellular Obtain food by photosynthesis Eukaryotic Mostly multicellular Obtain food by absorption Eukaryotic Multicellular or unicellular Obtain food by heterotrophism or photosynthesis Prokaryotic Often live in extreme environments ◦ High or low temperature ◦ High salt concentration Prokaryotic Cell wall contains peptidoglycan questions for review a.tissue, cell, organ, organ system b.atom, molecule, cell, tissue c.cell, tissue, organ system, organ d.tissue, cell, organ system, organ a.DNA carries genetic instructions. b.DNA transmits genetic information. c.DNA is present in most cells. d.DNA does not make up genes. a.Animalia b.Protista c.Fungi d.Plantae A. genus name b.order name c.species name d.family name a.prokaryotic cells contain nuclei, eukaryotic cells do b.prokaryotic cells contain DNA, eukaryotic cells do not c.prokaryotic cells lack nuclei and other membrane bound organelles, eukaryotic cells have membrane bound organelles d.prokaryotic cells are structurally more complex than eukaryotic cells a.a population b.a community c.an ecosystem d.biosphere a.systematics b.biology c.taxonomy d.evolution
