PLB 115 1st Edition Lecture 3Cells & their Components Previous Notes’ OutlineI. Characteristics of Living ThingsII. Levels of Organization in BiologyIII. Theories about Origin of Life (general)IV. Theories of Origin of Life on EarthV. Earth’s Early AtmosphereVI. Formation of CellsVII. Stanley Miller’s ExperimentVIII. Ideas about Formation of Organic Molecules into Complex MacromoleculesIX. RNA as First Genetic Materiala. Steps for Development of DNA-RNA Genetic SystemX. Development of MembranesCurrent Notes’ OutlineI. How Organisms Obtain EnergyII. Heterotroph vs Autotroph HypothesisIII. Development of an Oxidizing AtmosphereIV. First CellsV. Endosymbiotic TheoryVI. Prokaryotes vs EukaryotesVII. Cell MembranesVIII. Nucleus & it’s ComponentsIX. RibosomesX. Endoplasmic ReticulumXI. Golgi ApparatusXII. LysosomesHow Organisms Obtain Energy- Heterotrophs: Obtain energy from organic molecules in environment to build new organic molecules (transform to more complex molecules they can use)o Ex: Humans, most animals (pigs, cows, dogs)- Autotrophs: Use external energy source (like sunlight) to make organic molecules (simpler) from inorganic matter These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Heterotroph vs Autotroph HypothesisHeterotroph Hypothesis: 1st organisms on Earth were anaerobic (b/c atmosphere’s lack of oxygen) heterotrophs living off organic molecules in ocean. These organisms reproduced & depleted supply of organic molecules. Mutation produced organisms that could use inorganic molecules to make organic ones (autotrophs).Autotroph Hypothesis: 1st organisms were autotrophs that used energy released from inorganicchemical reactions to make organic molecules (like some primitive organisms that live in extremely harsh environments do). After exhaustion of raw inorganic molecules, mutation led toevolution of heterotroph creatures from autotrophs.Development of an Oxidizing Atmosphere- Bacteria, in photosynthesis, released oxygen as waste product- Ozone (O3) forms & reduces amount of ultraviolet radiationo ** Presence of oxygen allowed evolution of aerobic respirationFirst Cells- Prokaryotic (Bacteria)o Eukaryotic (Animals) cells evolved from Prokaryotes Eukaryotes= More complex ProkaryotesEndosymbiotic Theory- Prokaryotes came together to become one Eukaryoteo Bigger prokaryote swallowed smaller one (for protection) & smaller prokaryote provided larger prokaryote with extra energy: How organelles (mitochondria, chloroplasts) originated (once a smaller prokaryote)- Studies show organisms have genes from a variety of sources & organelles look like primitive prokaryotes, supporting Endosymbiosis theory Prokaryotes vs EukaryotesProkaryotic:• Simple, small (1-2 micrometers diameter)• Lack nucleus• Lack most other organelles- Ex: Bacteria & ArchaeaEukaryotic: More complex• Has nucleus• Variety of organelles• Typically bigger than prokaryotic cells (10-200 micrometers diameter)- Ex: Plants, animals, fungi, protozoa, and algaeCell MembranesThin sheets of phospholipids (phosphorous heads + lipid tails) & proteinso Separates the contents of the cell from the external environmento Functions: Metabolic activities, moving molecules across it, identification to other cells (Self vs. nonself), attachment sites for other cells, signal transductiono **Organelles with Cell Membranes: Endoplasmic reticulum, Golgi apparatus, Lysosomes, Peroxisomes, Vacuoles, Mitochondrion, Chloroplast, NucleusFluid-mosaic model• 2 phospholipid layers • Oily consistency• Materials move laterally within the bilayer• “Mosaic”= Proteins embedded within phospholipid bilayerMembrane Proteins- On surface, embedded in, protrude outo Functions: Transport molecules across membrane, provide attachment points for other cells, identity tags for cells (to recognize as own)Nucleus Components- Chromatin: (DNA+ Proteins) later condensed into chromosomes during cell division- Double membrane with pores- One+ nucleoli (make ribosomes)- Nucleoplasm: Water, nucleic acids, etc.Nuclear Membrane- Separates genetic material from the rest of cell- Filled with nucleoplasm- Porous to allow large molecules (RNA) pass through membrane into cytoplasmRibosomes- RNA + Proteinso Site of protein production- Found free floating in cytoplasm & attached to endoplasmic reticulumEndoplasmic ReticulumFolded membranes (giving LOTS of surface area for chemical reactions to occur) & tubes throughout cellTwo typeso Rough: Ribosomes on surfaceo Site of protein synthesiso Smooth: No ribosomeso Metabolizes fat & detoxifies damaging chemicalsGolgi ApparatusStacks of flattened membrane sacs- Modifies molecules made by other parts of cell- Makes some polysaccharides & lipidso Packages & ships these moleculesVesicles bring in molecules from ER containing proteins, vesicles fuse with golgi, golgi processes & ships out finished product to other parts of cell (other membranes) or vesicles become lysosomesLysosomes- Vesicles containing enzymes that digest macromolecules (Carbs, proteins, lipids, nucleic acids) & destroy disease-causing organisms & old organelles *Enzymes inside have low pH (5) so if lysosome breaks open, it will not damage the