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Essential Knowledge 1.B.1: Organisms share many conserved core processes and features that evolved and are widely distributed among organisms today. a.

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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 proteins that facilitate cell movement, morphological integrity and organelle transport) • Membrane-bound organelles (mitochondria and/or chloroplasts) Linear chromosomes Endomembrane 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 Regions Internal membranes facilitate cellular processes by minimizing competing interactions and by increasing surface area where reactions can occur Membranes and membrane-bound organelles in eukaryotic cells compartmentalize metabolic processes and enzymatic reactions Ex. ER, mitochondria, chloroplasts, Golgi, nuclear envelope Archaea 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 processes Ribosomes 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 smooth Rough 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 lipids Golgi is membrane-bound consisting of a series of flattened membrane sacs Functions in synthesis and packaging of material for transport and production of lysosomes Mitochondria capture and transform energy Double membrane allows compartmentalization Outer membrane is smooth, inner is highly folded (Cristae) Cristae contain enzymes important to ATP production, and increase surface area

10 4.A.2 cont Lysosomes are membrane-bound sacs that contain hydrolytic enzymes Intracellular digestion, organelle recycling, cell apoptosis Vacuoles 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 area Chloroplasts are found in algae and higher plants Structure enables it to capture light energy and convert it to chemical bonds Contain chlorophylls molecules (green color) which capture the light energy. Most common is chlorophyll a Have double outer membrane (compartmentalization). Energy capturing reactions in the thylakoids. Thylakoids are organized into stacks called grana and produce ATP and NADPH Carbon fixation occurs in the stroma via the Calvin cycle

11 Endosymbiont Theory

12 Endosymbiont Theory Evidence: Ribosomes Phospholipid bilayer
Mitochondria and chloroplasts were engulfed bacteria: Have DNA Semiautonomous Binary fission Similar in size to modern bacteria

13 Prokaryotic cells have a diameter of 1µm
Animal cells have a diameter of 10 µm Plant cells have a diameter of 100 µm Calculate 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 sequence ETC – (organization = efficiency) Enables feedback mechanisms Structure and function



20 Nucleus DNA Nuclear envelope Nucleolus

21 Nucleus DNA: Chromatin Chromosomes Genes

22 Nucleolus Composed of rRNA - produces ribosomes May have multiple

23 4.A.2 - Ribosomes Protein synthesis Non-membrane bound Free ribosomes
Prokaryotes have slightly different ribosome molecular structure (tetracycline, streptomycin) Free ribosomes Bound ribosomes (ER)

24 2.B.3, 4.A.2 - Endomembrane System
Phospholipid bilayer: Nuclear envelope ER Golgi Vesicles Lysosomes Vacuoles Plasma membrane

25 Endoplasmic Reticulum (ER)
Folded inner membrane Increased surface area/volume Chemical ‘laboratories’ Two kinds: _______, _________

26 ER Smooth - makes lipids, steroids phospholipids Rough ER
Adrenal glands; gonads, skin oil glands Detoxifies poisons/drugs Rough ER

27 Endomembrane System Vesicles

28 Endomembrane System - Golgi
Produce lysosomes Stores, modifies and sorts products from ER Secretion

29 Lysosomes Hydrolytic enzymes Intracellular digestion - phagocytosis
Tay-Sachs – build up of lipids, lack of lysosomal activity Arthritis – release of hydrolytic enzymes Intracellular digestion - phagocytosis Recycle - worn out organelles Remodeling - metamorphosis


31 Endomembrane System Vacuole: membrane-bound sac, larger than a vesicle
3 types and functions: Food vacuole - phagocytosis; intracellular digestion Water vacuoles - plants store water Contractile vacuole - ‘bladder’

32 Endomembrane System Contractile vacuole; fresh-water protozoa (paramecium) Excretes excess water out; osmosis constantly fills them up

33 Central Vacuole Water vacuole found in plant cells
Tonoplast; membrane around vacuole Storage - minerals, water (turgor pressure), poisons Helps provide shape, rigidity in plant cells

34 Endomembrane System - Review
2.B.3 - Internal membranes facilitate cellular processes by minimizing competing interactions and by increasing surface area where reactions can occur

35 2.B.3 - Membrane-bound Organelles In Eukaryotic Cells Compartmentalize Metabolic Processes and Enzymatic Reactions. Mitochondria and chloroplasts Peroxisomes

36 Energy Transducers Mitochondria and Chloroplasts Not endomembrane
Contain DNA and ribosomes Semiautonomous

37 Mitochondria Muscle, nerve, sperm mDNA

38 Chloroplasts

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 cell Movement – within and outside

41 Cytoskeleton 3 types of proteins: Microtubules Microfilaments
Intermediate filaments

42 Microtubules Straight, hollow fibers (tubulin - protein)
Maintain structure, support Move organelles within the cell Form cilia and flagella

43 Microtubules Centrosome - organelle that stores microtubules
Microtubules form from the MTOC Cilia and flagella Spindle apparatus during cell division Centrioles: - cylindrical structures outside the nucleus; replicate during prophase; grow spindle between Animal cells

44 Microfilament Actin - Globular protein wound into a helix
Smallest molecules of cytoskeleton Functions: Muscle cell contraction (along with myosin) Cleavage furrows during mitosis Cyclosis; cytoplasmic streaming (plants) Elongation of pseudopodia in amoeba; macrophages

45 Intermediate Fibers Between microtubules and microfilaments Framework
NOT dissasembled, reassembled frequently Keratins

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 Biofilms Extracellular matrix (DNA, proteins, polysaccharides – ‘slime coat’) secreted by microorganisms (bacteria, fungi) that eventually form a mat Microorganisms 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.

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