Chapter 2 Energy, Life,

1
Chapter 2Energy, Life, the Biosphere
2
2.2 Energy Nutrients

• All living things need energy!
• Chemical energy the energy stored in the
  molecules from which the organisms are made
• aka the energy in the food you eat or within
  your body

3
2.2 Energy Nutrients

• Free energy the portion energy that is
  available to do work
• Ex The energy youre using right now to stay
  awake, to exercise, to grow, etc.
• FREE doesnt mean costing nothing or being
  freely available all around its best to think
  of this concept as USABLE energy

4
2.2 Energy Nutrients

• Gibbs Free Energy (Mr. Hs lecture)
• Whether or not a reaction occurs spontaneously
  (without an input of energy) depends strongly on
  the temperature
• This is important in biology because many of
  lifes processes have to occur spontaneously for
  life to continue

5
2.2 Energy Nutrients

• Energy use by cells - Cells need a constant
  supply of free energy for work
• Chemical work that involves breaking down
  making complex molecules like proteins
• Transport moving nutrients (raw materials for
  chemical work)
• Mechanical movement (like muscle contractions)

6
2.2 Energy Nutrients

• Obtaining energy
• Heterotrophs Organisms that obtain energy
  nutrients from consuming other organisms (living
  or dead)
• Ex animals, fungi, some bacteria
• Autotrophs Organisms that get their energy
  nutrients from nonliving sources (sun or
  inorganic materials)
• Ex plants some bacteria

7
2.2 Energy Nutrients

• 2 Kinds of autotrophs
• - Photoautotrophs use energy from the sun to
  perform photosynthesis to build sugars (chemical
  energy)
• - Chemoautotrophs use chemosynthesis to
  capture energy from inorganic chemicals (like
  sulfur) that can then be used for work

8
2.2 Energy Nutrients

• Cellular Respiration
• Process used by BOTH autotrophs heterotrophs
  that release the free energy in compounds

9
2.3 Energy and Ecosystems

• Mostly definitions that have been used doing the
  food web activities.

10
2.4 Energy Conversions

• First Law of Thermodynamics energy CANNOT be
  created or destroyed (also known as the
  conservation of energy)
• The total energy of the universe is constant. It
  can change forms (electricity, solar, chemical,
  etc.)

11
2.4 Energy Conversions

• Chemical Energy (log example)
• Chemical energy is stored in the molecules of a
  substance
• Imagine a log the chemical energy is stored in
  the logs molecules
• When the log is burned, the chemical
• energy changes mostly into heat energy
• which is lost to the surroundings a small
• amount of chemical energy remains in the
• smoke and ash

12
2.4 Energy Conversions

• Energy in organisms
• Organisms CANT create energy
• Autotrophs convert solar energy or the chemical
  energy of inorganic molecules to usable energy
• Heterotrophs take in chemical energy from the
  food they eat

13
2.4 Energy Conversions

• Wolf example
• A wolf eats a deer as a source of energy
  nutrients the deer is digested into simple
  compounds (glucose, fatty acids, amino acids)
  the wolfs cells break these compounds down even
  further to release free energy which is then used
  for cellular work (muscle movement, growth,
  tissue repair, etc.)

14
2.4 Energy Conversions

• Wolf vs. Log example
• Just like the log, the wolf releases some of the
  energy as heat but when the chemical energy is
  converted in the wolf, it releases FREE ENERGY to
  do the work of the cells
• Using this free energy for the work of cells is
  one distinction between living nonliving things
  (Energy 1 of the characteristics of living
  things)

15
2.4 Energy Conversions
16
2.5 Energy Entropy

• Not all energy from food is useful when heat
  energy is released to surroundings, it can no
  longer do work
• When energy is lost to surroundings, the free
  energy in a system is slightly less after each
  energy conversion

17
2.5 Energy Entropy

• Second Law of Thermodynamics
• Systems change in a way that INCREASES the
  disorder entropy - of the system
• The world becomes more disordered as free energy
  is released (Entropy increases)

18
2.5 Energy Entropy

• 2nd Law of Thermodynamics Organisms
• Organisms need to be well organized to remain
  alive to grow
• Ex A seed a tree embryo which develops into a
  mature, complex, organized tree Free energy was
  required for the tree to grow the source of
  this energy was sunlight harnessed by
  photosynthesis

19
2.5 Energy Entropy

• So, the key to maintaining organizaiton is
  ENERGY.
• The flow of energy in an ecosystem is
• light ? chemical energy (in producers)
• Chemical energy is then converted and free
  energy is used in all living things for work.

20
2.5 Energy Entropy
21
Energy in Food Webs/Chains

• As energy flows in a food web, most is loss as
  heat energy and some is used as free energy

22
The 10 Rule

• On average, only about 10 of the energy in any
  trophic level will be incorporated into the next
  level

23
(No Transcript)
24
2.6 Enzymes Energy

• Chemical Reactions in Living Things
• Breaking or making new bonds require a narrow
  range of temperatures. These temps are too low
  to supply activation energy - the energy needed
  to start a reaction.

25
2.6 Enzymes Energy

• Enzymes and Catalysts
• Enzymes are biological catalysts, or chemicals
  that speed up chemical reactions. They do so by
  lowering the activation energy.

26
2.6 Enzymes Energy

• Some special characteristics of enzymes
• -they are specific to a few reactions, at most
• -they are reusable, as they are not consumed by
  reactions
• - they dont alter the equilibrium of the
  equation
• - almost all enzymes are proteins

27
2.6 Energy Enzymes
http//highered.mcgraw-hill.com/sites/0072495855/s
tudent_view0/chapter2/animation__how_enzymes_work.
html

• Functioning of Enzymes
• -The specific type of reaction depends on the
  tertiary structure of the protein in a small area
  called the active site.
• - The active site matches the fit of the
  substrate(s), or the reacting molecule(s).
• - The close fit of the substrate and enzyme is
  called the enzyme-substrate complex (ESC).
• - The interaction of the ESC reduces the
  activation energy and the reaction occurs. The
  product(s) breaks away from the enzyme.

28
2.7 Chemical Reactions in Organisms

• Metabolism
• All of the chemical reactions and activities that
  take place in an organism are called metabolism.
  There are two types of metabolic reactions

29
2.7 Chemical Reactions in Organisms

1. Synthesis reactions - form larger and more
   complex molecules from smaller ones. These
   reactions consume free energy and allow organisms
   to grow and maintain structure. ex
   photosynthesis
2. Decomposition reactions - break down larger
   molecules into smaller ones. The stored energy
   is released and is available for other work. ex
   cellular respiration

30
2.8 Energy Transfer ATP

• How does decomposition release free energy?
• Oxidation a type of decomposition that removes
  electrons from a molecule (which
  breaks/rearranges bonds)
• Energy released as heat free energy
• Heat waste energy
• Free energy follows a series of electron
  transfers and eventually ends up in a molecule -
  ATP

31
2.8 Energy Transfer and ATP

• ATP adenosine triphosphate

Allows free energy to be available in chemical
form.
32
2.8 Energy Transfer and ATP

• ATP a nucleotide with 2 additional phosphates ?
  adenine (Nitrogen base) bonded to a ribose
  (sugar) bonded to 3 phosphate groups
• It is an efficient useful energy transfer
  molecule because when energy is needed the bond
  between the 2nd 3rd phosphates breaks and
  releases free energy

33
2.8 Energy Transfer and ATP

• With the phosphate free energy released, the
  molecule is then called ADP adenosine
  diphosphate.

34
2.8 Energy Transfer and ATP
The ATP ADP Cycle
35
2.8 Energy Transfer and ATP

• ATP is continually synthesized broken down in
  cells
• ATP is responsible for providing the free energy
  for almost all of an organisms metabolism
• Cells need the energy for biosynthesis (making
  organic compounds), removing wastes, taking in
  nutrients, maintaining ion levels, moving around,
  etc.

36
Lets put it all together follow the energy
flow from the sun all the way to the ATP Cycle.
Solar energy is converted into Chemical energy of
glucose when autotrophs (producers) perform
photosynthesis.
The chemical energy is stored in the autotroph.
37
Energy Flow.
A heterotroph consumes the autotroph. The
heterotroph performs cellular respiration, which
releases free energy.
The free energy follows a series of electron
transfers and ends up within a molecule of ATP.
38
Energy Flow
Once in ATP, free energy can be released for
cellular work by breaking a phosphate bond,
creating an ADP molecule a
phosphate.
This released energy can then be used for
metabolism.
39
Energy Flow.
REMEMBER.. During each step of the way, some of
the energy is lost as heat energy waste energy