16 and 21 November

blessinghomoeopathΤεχνίτη Νοημοσύνη και Ρομποτική

30 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

108 εμφανίσεις

Attributes of Life

16 and 21 November


Introduction to life


Themes/characteristics of living organisms


Structural and functional characters

Introduction


What defines life?


________________


________________


________________

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

Hierarchical Nature of Living
Systems

Community



Population


Organism


Organ


Tissue


Cell


Organelles


Macromolecules


Atoms

Infrastructure

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

General Cell Structures

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

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)

Examples of Open Systems

26
-
580

Figure 26.41

Eye

Sun
-
Tracking Plants

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

Regulatory Systems: Cybernetics










Feedbacks (+ and
-
), homeostasis and cybernetics

Control
Center/

Sensor

Set Point

Effector

Positive

Feedback

Negative

Feedback

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)

Energy Utilization


Three related activities: acquisition, utilization, and
storage


Energy Acquisition


Energy capture (autotrophs; heterotrophs)


Energy utilization


Laws of Thermodynamics (1
st

and 2
nd

laws)


ATP

(adenosine triphosphate) and
ADP

(adenosine
diphosphate


Energy storage


Chemical bonds (C
-
C covalent bonds)


Starch, glycogen and lipids

Energy Utilization


Catabolism



Biosynthesis/
Anabolism


ADP

ATP

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)

What is Life? “Nuts and Bolts”



Introduction to life


Themes/characteristics of all living
organisms


Cardinal structural and functional
characters


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

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

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

Diffusion

23
-
479

Figure 23.5

1
.

10
-
5

m

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

Energy
Needed

Reactants

Products

“Hill”


Base case for
reactions to occur


Reactants


Products


Energy analysis
(thermodynamics)


Energy to cause
reaction to occur
(over the “hill”)

Enzymes: How They Work

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 > 10
6

orders of magnitude

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)

Membranes: Structure


Lipid bilayer: “fluid membrane” with floating
chunks of proteins and carbohydrates (i.e.,
icebergs)

Lipid Bilayer

Protein Chunk

Proteins in Lipid Bilayer

Membranes: Functions


Example of hierarchy theory and emergent
properties


Selective permeability


Signaling: cell
-
to
-
cell communication

Transport through Membrane:
Selective Permeability

Signaling in/on Membranes

Cystic fibrosis


Vaccinations


Allergies

Water: Medium for Metabolism


Liquid medium for metabolism and its importance


Role of water (H
2
O)


Physical properties (e.g., polarity, phases)


Chemical properties (e.g., pH, solution)


Exquisite and unique properties of H
2
O

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

General Cell Structures

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

Compartmentation

23
-
494

Figure 23.22

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

Omissions


Cell cycle (pp. 478
-
482)


Controlled methods transport (pp. 464
-
465)


Non
-
membraneous organelles (pp. 474
-
475)


Nuclear component (p. 475)


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?


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.