Presentation on theme: "Essential Knowledge 1.B.1: Organisms share many conserved core processes and features that evolved and are widely distributed among organisms today. a."— Presentation transcript:
1 Essential Knowledge 1.B.1: Organisms share many conserved core processes and features that evolved and are widely distributed among organisms today. a. Structural and functional evidence supports the relatedness of all domains.Claim: because extant organisms share processes and structures it indicates that they evolved from a common ancestor (similarity implies ancestry).
2 • Cytoskeleton (a network of structural proteins Structural evidence supports the relatedness of all eukaryotes. [See also 2.B.3, 4.A.2]To foster student understanding of this concept, instructors can choose an illustrative example such as:• Cytoskeleton (a network of structural proteinsthat facilitate cell movement, morphologicalintegrity and organelle transport)• Membrane-bound organelles (mitochondriaand/or chloroplasts)Linear chromosomesEndomembrane systems, including the nuclear envelope
3 Evidence:DNA, RNA in extant organisms are all made of the same nucleotides, have same shape and structure, function in the same way; (genes are genes are genes).Protein synthesis, photosynthesis and respiration are similar in all organisms.
4 1.B.1 Evidence of Evolution Comes From Cells Claim: All eukaryotes have similar structures indicating they come from a common ancestor:Evidence: All eukaryotic cells have a cytoskeleton, membrane-bound organelles, linear chromosomes, endomembrane systems
5 2.B.3 – Eukaryotic Cells Maintain Internal Membranes That Partition the Cell Into Specialized RegionsInternal membranes facilitate cellular processes by minimizing competing interactions and by increasing surface area where reactions can occurMembranes and membrane-bound organelles in eukaryotic cells compartmentalize metabolic processes and enzymatic reactionsEx. ER, mitochondria, chloroplasts, Golgi, nuclear envelopeArchaea and Bacteria generally lack internal membranes and organelles and have a cell wall
8 4.A.2 – The structure and function of subcellular components and their interactions provide essential cellular processesRibosomes are small structures made of ribosomal RNA and protein. These cellular components interact to become the sites of protein synthesis where the translation of the genetic information produces polypeptides.
9 Endoplasmic reticulum occurs in two forms; rough and smooth 4.A.2 cont.Endoplasmic reticulum occurs in two forms; rough and smoothRough compartmentalizes the cell. Serves as mechanical support, provides site-specific protein synthesis with membrane-bound ribosomes and plays a role in intracellular transport.Smooth ER synthesizes lipidsGolgi is membrane-bound consisting of a series of flattened membrane sacsFunctions in synthesis and packaging of material for transport and production of lysosomesMitochondria capture and transform energyDouble membrane allows compartmentalizationOuter membrane is smooth, inner is highly folded (Cristae)Cristae contain enzymes important to ATP production, and increase surface area
10 4.A.2 contLysosomes are membrane-bound sacs that contain hydrolytic enzymesIntracellular digestion, organelle recycling, cell apoptosisVacuoles are membrane-bound sacs that function in intracellular digestion and release of waste products. Plant vacuoles store water, poisons, and pigments. A large centralized vacuole allows for increased surface areaChloroplasts are found in algae and higher plantsStructure enables it to capture light energy and convert it to chemical bondsContain chlorophylls molecules (green color) which capture the light energy. Most common is chlorophyll aHave double outer membrane (compartmentalization). Energy capturing reactions in the thylakoids. Thylakoids are organized into stacks called grana and produce ATP and NADPHCarbon fixation occurs in the stroma via the Calvin cycle
12 Endosymbiont Theory Evidence: Ribosomes Phospholipid bilayer Mitochondria and chloroplasts were engulfed bacteria:Have DNASemiautonomousBinary fissionSimilar in size to modern bacteria
13 Prokaryotic cells have a diameter of 1µm Animal cells have a diameter of 10 µmPlant cells have a diameter of 100 µmCalculate the SA/V ratio of each and explain how eukaryotic cells can survive even though they are considerably larger than prokaryotic cells.
14 Eukaryotic organisms can attain large size by having many small cells
15 Increased surface area means increased exposure to the environment. Branching of lungs, absorption of nutrients by intestines, filter feeding animals, loss/gain of heat (thermoregulation).
16 SA/V and Thermoregulation – the higher the SA/V, the more heat is lost/gained from environment
17 Internal Membranes: Create compartments Isolate competing chemical reactions (dehydration, hydrolysis)Embed/hold enzymes in correct sequenceETC – (organization = efficiency)Enables feedback mechanismsStructure and function
39 Peroxisomes Detoxification: liver cells Use H2O2 and catalase to breakdown alcohol
40 Cytoskeleton Protein fibers in the cytosol Functions: Framework and support for the cellMovement – within and outside
41 Cytoskeleton 3 types of proteins: Microtubules Microfilaments Intermediate filaments
42 Microtubules Straight, hollow fibers (tubulin - protein) Maintain structure, supportMove organelles within the cellForm cilia and flagella
43 Microtubules Centrosome - organelle that stores microtubules Microtubules form from the MTOCCilia and flagellaSpindle apparatus during cell divisionCentrioles: - cylindrical structures outside the nucleus; replicate during prophase; grow spindle betweenAnimal cells
44 Microfilament Actin - Globular protein wound into a helix Smallest molecules of cytoskeletonFunctions:Muscle cell contraction (along with myosin)Cleavage furrows during mitosisCyclosis; cytoplasmic streaming (plants)Elongation of pseudopodia in amoeba; macrophages
45 Intermediate Fibers Between microtubules and microfilaments Framework NOT dissasembled, reassembled frequentlyKeratins
46 2.D.1 – All biological systems from cells and organisms to populations, communities and ecosystems are affected by complex biotic and abiotic interactions involving exchange of matter and free energy.Ex. Cell density, biofilms, temperature, water availability, sunlight
47 BiofilmsExtracellular matrix (DNA, proteins, polysaccharides – ‘slime coat’) secreted by microorganisms (bacteria, fungi) that eventually form a matMicroorganisms communicate chemically to determine if there is a ‘Quorum’ of other bacteria and ‘decide’ what to do (example of: cell-to-cell communication); grow or split off to colonize other areas.