Download Where is the energy transfer?

February 14, 2014
Pick up the handout
and schedule
from the front
1st Law of Thermodynamics
The energy of the universe is
constant. Energy can be
transformed & transferred, but it
cannot be created or destroyed.
2nd Law of Thermodynamics
Every energy transfer or
transformation makes the universe
more disordered. In other words,
every energy transfer or
transformation increases the
entropy of the universe
Based on free energy changes, reactions can be classified as exergonic
(energy outward) or endergonic (energy inward). An exergonic reaction
proceeds with a net release of free energy. They occur spontaneously.
An endergonic reaction is one that absorbs free energy from its
surrounds; the energy is stored in the product; they are nonspontaneous.
Energy Transfer
Here is a food pyramid that begins with producers
and ends with tertiary consumers. If the producer
level contains 25,000 kJ of energy and this
pyramid follows the 10% rule, then how much
energy gets transmitted to the tertiary consumers?
25 kJ
All of the questions are printed at the back of your handout
Carbon Flow in a Grassland Ecosystem
How much carbon (g/m2) is released into the
atmosphere as a result of the metabolic activity of the
herbivores?
42 g/m2
ΔG = ΔH – TΔS
G = Free Energy
H = Enthalpy
S = Entropy
T = Temperature in Kelvin
Δ represents change in value over time
An experiment determined that when a protein unfolds to
its denatured (D) state from the original folded (F) state,
the change in Enthalpy is ΔH = H(D) – H(F) = 56,000
joules/mol. Also the change in Entropy is ΔS = S(D) –
S(F) = 178 joules/mol. At a temperature of 20⁰C,
calculate the change in Free Energy ΔG, in j/mol, when
the protein unfolds from its folded state.
The correct answer is 3,846 joules/mol.
ΔG = ΔH – TΔS
ΔG = (56,000 joules/mol) – 293 K (178 joules /mol)
ΔG = 56,000 joules/mol – 52,154 joules/mol = 3,846 joules/mol
A + B + energy → AB
There are many types of biochemical reactions taking
place in any living system. Which of the following
best characterizes the reaction represented above?
A) Catabolism
B) Oxidation-reduction
C) Exergonic reaction
D) Endergonic reaction
Energy Transfer
When you compare the formula for photosynthesis
with cellular respiration, which is exergonic, which
is endergonic? They are both oxidation/reduction
reactions.
6CO2 + 6H20 + energy  C6H12O6 + 6O2
C6H12O6 + 6O26CO2 + 6H20 + energy
becomes oxidized
C6H12O6 + 6O2
6CO2 + 6H2O + Energy
becomes reduced
6CO2 + 6H20 + energy  C6H12O6 + 6O2
C6H12O6 + 6O26CO2 + 6H20 + energy
CELLULAR RESPIRATION- AN OVERVIEW
Where is the energy transfer?
Where is the energy transfer?
A molecule that is phosphorylated:
a.Has an increased chemical reactivity; it is primed
to do cellular work
b.Has a decreased chemical reactivity; it is less
likely to provide energy for cellular work
c.Has been oxidized as a result of a redox reaction
involving the gain of inorganic phosphate
d.Has been reduced as a result of a redox reaction
involving the loss of an inorganic phosphate
Which of the following statements describes the
results of this reaction?
C6H12O6 + 6O2 6CO2 + 6H20 + energy
a. C6H12O6 is oxidized and O2 is reduced
b. O2 is oxidized and H20 is reduced
c. CO2 is reduced and O2 is oxidized
d. C6H12O6 is reduced and CO2 is oxidized
Starting with one molecule of glucose, the
“net” products of glycolysis are:
a.2 NAD+, 2 H+, 2 pyruvate, 2 ATP and 2 H20
b.2 NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H20
c.2 FADH2, 2 pyruvate, 4 ATP and 2 H20
d.6 CO2, 6 H20, 2 ATP and 2 pyruvate
Where is the energy transfer?
Pyruvate
(from glycolysis,
2 molecules per glucose)
CO2
NAD+
Glycolysis
Citric
acid
cycle
ATP
ATP
Oxidation
phosphorylation
CoA
NADH
+ H+
Acetyl CoA
CoA
Where is the energy transfer?
CoA
Citric
acid
cycle
FADH2
2 CO2
3 NAD+
3 NADH
+ 3 H+
FAD
ADP + Pi
ATP
ATP
Where is the energy transfer?
Where is the energy transfer?
Where is the energy transfer?
Where is the energy transfer?
There is “compartmentalization” within the
mitochondrion. What purpose does it serve?
How is a concentration gradient important in
the process shown here?
What is the significance of the inner membrane
being folded?
Where is the energy transfer?
Add it all up-
This is probably
26-28 ATP
This number is
Probably lower
The oxygen consumed during cellular respiration
is involved directly in which process or event?
a.Glycolysis
b.Accepting electrons at the end of the end of the
electron transport chain
c.The citric acid cycle
d.The oxidation of pyruvate to acetyl CoA
Organic molecules
besides carbohydrates
can transfer energy
Which process in eukaryotic cells will proceed
normally whether O2 is present or not and
therefore probably evolved first?
a.Electron transport
b.Glycolysis
c.The citric acid cycle
d.Oxidative phosphorylation
You have a friend who lost 7 kg (about 15
pounds) of fat on a low carb diet. How did
the fat leave her body?
a. It was released as carbon dioxide
and water
b. Chemical energy was converted to
heat and released
c. It was converted to ATP, which weighs
less than fat
d. It was converted to urine and
eliminated from the body
Photosynthesis
!!!
Relate the structure to the functionWe have compartmentalization again
Lots of surface area
Relate structure and function-At the organ level
-At the tissue level
-At the cellular level
-At the molecular level
Photosynthesis- An Overview
Where is the energy transfer?
Where is the energy transfer?
Where is the energy transfer?
Where is the energy transfer?
C3 Plants
Where is the energy transfer?
Use these terms to summarize the Calvin Cycle.
Carbon dioxide (CO2)
Ribulose biphosphate (RuBP)
Rubisco
3-phosphoglycerate
ATP
NADPH
Glyceraldehyde-3-phosphate (G3P)
Glucose
In the Calvin Cycle, CO2 is attached to a molecule of RUBP. This is
catalyzed by the enzyme rubisco. The six carbon product splits,
forming two molecules of 3-phosphoglycerate. 3-phosphyglycerate
receives a phosphate from ATP and electrons from NADPH forming a
molecule of G3P. Two molecules of G3P can combine to form a
molecule of glucose.
Where is the energy transfer?
Photosynthetic Adaptations
Alternate mode of carbon
fixation that forms a 4-carbon
compound as its first product.
A way to cut down on photorespiration.
Sugarcane, corn, members of
the grass family (at least 1000 plants)
CAM Photosynthesis
Evolved in succulent plants, many cacti, pineapples &
other plants. Open stomata during night, close during day
Compare and contrast the energy transfer in mitochondria & chloroplas
Energy Flow in a Hardwood Forest
What percentage of the biomass in the forest community is tied up in the
Grass layer which has a question mark?
The End