Attributes of Life 16 and 21 November

1. Attributes of Life16 and 21 November • Introduction to life • Themes/characteristics of living organisms • Structural and functional characters

2. Introduction • What defines life? • ________________ • ________________ • ________________

3. Themes • Hierarchy theory and emergent properties • Structure: “it is the cell” • Continuity of life: function of “information” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to acquire, utilize, and store energy • Diversity and similarity of living systems

4. Hierarchical Nature of Living Systems Community Population Organism Organ Tissue Cell Organelles Macromolecules Atoms

5. Infrastructure

6. Cell: Structure and Function • Organism’s basic unit of structure and function • Lowest level of structure capable of performing life’s activities (e.g., irritability, reproduce, grow, develop, etc.) • Most common basic structure of all living organisms • Cell Theory • Ubiquitous nature of cells • All cells come from previous cells

7. General Cell Structures

8. Continuity of Life and Information • Order in any system originates from instructions serving as a template for organization (e.g., Constitution, Bill of Rights) • In living systems, instructions codified in the DNA • Instructions/inheritance based on the precise, sequential order of nucleotides (ATCG) • Example: RAT versus TAR versus ART

9. Open Systems • All living organisms are open systems, allowing organisms to interact with their environment • Processing stimuli • Responding to stimuli • “Open” versus a “closed” system • Examples • Orientation of leaves to sun • Eyes • Microbes and single cell organisms (e.g., amoeba)

10. Examples of Open Systems Eye Sun-Tracking Plants Figure 26.41 26-580

11. Regulatory Systems • Interplay of organisms with the environment requires a well balanced regulatory system • Outcome: homeostasis • Set point, effectors, control centers and sensors • Analogy: thermostat for heat control • Examples • Enzymes in cells (lab exercise this week) • Thermostatic control of body temperature • pH of the cell

12. Positive Feedback Control Center/ Sensor Set Point Effector Negative Feedback Regulatory Systems: Cybernetics • Feedbacks (+ and -), homeostasis and cybernetics

13. Universality of Reproduction • Reproduction: regenerative process of making new organisms (not necessarily copies) • Methods • Sexual • Asexual (microbes; cell division/mitosis) • Ancillary but important function: creating new variants • Examples • Siblings • Geranium plants • Dolly (the sheep)

14. Energy Utilization • Three related activities: acquisition, utilization, and storage • Energy Acquisition • Energy capture (autotrophs; heterotrophs) • Energy utilization • Laws of Thermodynamics (1st and 2nd laws) • ATP (adenosine triphosphate) and ADP (adenosine diphosphate • Energy storage • Chemical bonds (C-C covalent bonds) • Starch, glycogen and lipids

15. Energy Utilization ADP Catabolism Biosynthesis/Anabolism ATP

16. Two Sides of a Coin: Diversity and Similarity • Diversity is a hallmark of living systems • 1.5 M known species of plants, animals and microbes • 100 M+ thought to exist • Similarity is a hallmark of living systems • Striking similarity at the molecular level (DNA): kinship to worms, squirrels, birds and pigs (you DNA is ~90% pig) • Examples • Biochemistry • Structure and morphology • DNA • DNA phylogeny lab (December)

17. What is Life? “Nuts and Bolts” • Introduction to life • Themes/characteristics of all living organisms • Cardinal structural and functional characters

18. Structural and Functional Characters • Cells as the physical infrastructure • Biological catalysis: enzymes • Cell membranes • Water as the medium of life • Polymers (C-based polymers) • Compartmentation via organelles • Major types of cells

19. Cells as the Physical Infrastructure • Cell theory • All organisms composed of cells • Cells as smallest unit of organization exhibiting characteristics of life • Structure Cell Membrane Nucleus Cytoplasm

20. General Features of a Cell • Size correlated with function • Upper limit: 0.00001 m (1 x 10-5 m) • Relationship of volume to distance • Anything over 1 x 10-5 m is nonfunctional • Efficacy of transport/diffusion

21. Diffusion 1 . 10-5 m Figure 23.5 23-479

22. Enzymes • Introduction • Reactions are very slow (not sufficient to sustain life) • Mechanisms to accelerate specific reactions preferentially • Accelerants = Catalysts = Enzymes • Proteins (relate to information brokers) • Change rate of reactions • High degree of specificity • Regenerated

23. Enzymes: How They Work • Base case for reactions to occur • Reactants • Products • Energy analysis (thermodynamics) • Energy to cause reaction to occur (over the “hill”) “Hill” Energy Needed Reactants Products

24. How Enzymes Work • Efficacy of enzymes: “Hill” height • Mechanism • Lower the height of the “hill” • Selectivity/specificity • Protein 3-D structure (1, 2, 3, and 4 protein conformation) • Conclusion • Absence of enzyme: minutes to hours to days to years • Presence of enzyme: 1,000 - 10,000 reactions per second • Increase in rate > 106 orders of magnitude

25. Membranes: Structure • Membranes: complex polymer, with principal monomer (lipid) being a fatty acid + glycerol (i.e., phospholipids) • Lipid bilayer at the molecular level Phosphate/ Glycerol (Hydrophilic) Fatty Acid (Hydrophobic)

26. Membranes: Structure • Lipid bilayer: “fluid membrane” with floating chunks of proteins and carbohydrates (i.e., icebergs) Lipid Bilayer Protein Chunk

27. Proteins in Lipid Bilayer

29. Membranes: Functions • Example of hierarchy theory and emergent properties • Selective permeability • Signaling: cell-to-cell communication

30. Transport through Membrane: Selective Permeability

31. Signaling in/on Membranes Cystic fibrosis Vaccinations Allergies

32. Water: Medium for Metabolism • Liquid medium for metabolism and its importance • Role of water (H2O) • Physical properties (e.g., polarity, phases) • Chemical properties (e.g., pH, solution) • Exquisite and unique properties of H2O

33. Biological Macromolecules • Define polymer….. • Major biomacromolecules of carbon • Carbohydrates (monomer is ______) • Lipids (monomer is _______ + _______) • Proteins (monomer is ____________) • Nucleic acids (monomer is __________) • “Information brokers”, particularly for nucleic acids • Analogy to an alphabet

34. General Cell Structures

35. Principle of Compartmentation • Cells are compartmentalized • Elaborate and organized infrastructure • Analogy to a dorm • Corridors as endoplasmic reticulum • Rooms as organelles • Consequence of not being compartmentalized

36. Compartmentation Figure 23.22 23-494

37. Cell Types • Prokaryotes • No typical nucleus • No mitochondria, chloroplasts, Golgi, or endoplasmic reticulum • DNA, enzymes, metabolize, etc. • Example: bacteria • Eukaryotes • True nucleus and all the organelles • Plant eukaryotes • Chloroplast for photosynthesis and cell wall • Animal eukaryotes

38. Omissions • Cell cycle (pp. 478-482) • Controlled methods transport (pp. 464-465) • Non-membraneous organelles (pp. 474-475) • Nuclear component (p. 475)

39. When you contract a fever, your body temperature is elevated. Is fever and inadvertent consequence of the infection or is it an example of homeostasis?

40. Each of you has been vaccinated for multiple childhood diseases. You may or may not have taken a flu vaccine. Explain how membrane and information attributes of living systems underpin the efficacy of vaccinations.