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CHAPTER 2: ENERGY, LIFE & THE BIOSPHERE

Bioenergetics:

 Characteristics of Organisms:  

·        Reproduce:

·        Grow:

·        Develop:

·        Take in & convert materials and E from environment; release wastes

·        Have

·        Complex

·        Sense & react to environment -

Homeostasis: 

·        Communicate

·        Move

 

 

ENERGY & NUTRIENTS 

Energy (E): Ability to do work or cause change

·        Chemical Work ->

·        Transport Work ->

·        Mechanical Work ->

 

Energy Types:

·        ________________________ Potential E -> E trapped or stored in bonds in organic compounds (OC)  

·        _________________________ – Useable E; Kinetic E -> released during chemical rxns when bonds are broken in OC

 

How Organisms Obtain Nutrients 

1.             Heterotrophs – 

Undergo Cellular Respiration, an Exergonic Rxn (releases E)      when breaking down OC:    

 C₆H₁₂O₆ + O₂ - - -> CO₂ + H₂O + free E

 2.             Autotrophs –

 

Undergo Photosynthesis, an Endergonic Rxn (taking in E) by trapping the sun’s E in bonds of OCs:

 CO₂ + H₂O + E (sun) - - - > C₆H₁₂O₆ + O₂

  

Photoautotrophs (Photosynthesizers)	Chemoautotrophs (Chemosynthesizers)

Fig. 2.5:

 

 

 

 

CALORIES

·        calorie (c) =

·        kilocalorie (C) = 

·        Nutrient E content:

Carbs & proteins -> ____kcal/g
Lipids -> ____ kcal/g

Which OC contains the most E per gram? ______________

  

ENERGY & ECOSYSTEMS

The _________ is the ultimate source of E for all organisms

 Ecosystems – 

Composed of:

·        Abiotic factors -

·        Biotic factors - 

Organisms in an Ecosystem: 

·        Producers:

·        Consumers:

Primary Consumers-

Secondary, Tertiary Consumers-

·        Decomposers: 

    

     (bacteria, fungi)

  

Food Chain: Path of materials & potential E from organism to organism within an ecosystem. Ex:

 

   Grass  ®           Mouse     ®          Fox          ®           Lion  ®      Bacteria

(producer)     (primary consumer)     (secondary cons)  (tertiary cons)   (decomposer)

 

Food Web: All food chains together. Ex:

 

 

 

 

 

 

 

Habitat:

Biosphere:

 

 

ENERGY FLOW

·        First Law of Bioenergetics – 

 

(amt of E remains the same).

 

  

 

ENERGY & ENTROPY

·        Second Law of Bioenergetics – 

 

E _____________________________________ b/c it is ___________________ (not useable form). Organisms are not E efficient- they counteract entropy by constantly obtaining E.

  

 

 

 

Energy Pyramid (The 10% Rule)

 

 

 

 

 

METABOLISM & ENERGY TRANSFER 

·       

·       

·       

 

Catalysts – C hemicals that:

  

 

 

 

 

 

 

Enzymes –

·       

·        __________________ – used again & again, not changed by rxns

·        End in “ase” – 

·        Reaction-specific: 

 

 

Induced Fit Model:

 

 

 

 

 

Factors Affecting Rate of Enzyme Action

·        ___________________ – enzymes denature (break down) in extreme heat

·        __________

·        ___________________________________ – Max rate achieved when all enzymes joined to substrate

  

METABOLISM – 

ALL rxns require __________________ & _____________________.

 

Biosynthesis/ Dehydration Reactions, a.k.a. Anabolism - “Building up”

·       

·        Ex: joining amino acids -> proteins

·        Ex:

 

Decomposition/ Hydrolysis Reactions, a.k.a. Catabolism – “Breaking down”

·       

·        Ex:

·        Bonds are ______________ & _______________

·        Heat lost by catabolism used to _____________________.

·        Release free E through Oxidation, _______________________ from a molecule

·        Available _________________________ to another molecule through Reduction.

·        _____________________ are transferred along with electrons.

                                                    ox
CH3-CH2-OH (ethanol) ---> CH3-CH=O + 2e^- + 2H⁺
                                    <-----
                                    Redux

 

(OIL RIG)

Oxidation is __________; Reduction is _________

  

 

 

ENERGY TRANSFER & ATP

 Flow of E in Animal Cells:

Nutrients ® _________ ® Cell Work

 

ATP (_______________________________)

                                                            

·       

·       

·        Building Block = Nucleotide: ________________ + __________________ + __________________  linked by high energy bonds:

 

 

 

 

 

·        Continually synthesized & broken down in cells

·        Phosphorylation:

·        Necessary molecule __________________ (no ATP = death)

·        ______ & ______ are also energy carriers

 

Fig 2.19: