Download PP Cellular Energy

Some Questions to Consider
What do we need energy for?
How do we get energy to do these
things?
Cellular Respiration
And ATP Formation
Energy comes in lots of different forms
• To do a particular job you need the
right kind of energy
A wind farm can be used to transform
wind energy into a useable form
Wind turns the turbines and wind
energy is transformed into kinetic
energy
This is then transformed into electrical
energy, which comes through wires to
your house and enables the CD player
to function.
Wind energy  kinetic energy electrical energy
Similarly…..
• Energy in the form of carbohydrates (
• Energy in fats
• Energy in the carbon skeleton of amino
acids
is not in a form that cells can use directly
• Transforming the energy
contained in simple organic
molecules like Glucose into
useable energy requires an
energy converter
In eukaryotic cells
mitochondria do
most of this
transformation
General equation for aerobic
respiration:
C6H12O6
Glucose
+
6O 2
oxygen
6CO2
+
carbon dioxide
Energy transformation
Chemical --------Chemical
(glucose)
(ATP)
6H2O
water
+
36ATP
energy
ABOUT ATP
• The energy in glucose and other
organic compounds is not used directly
by cells. It is transferred into molecules
of ATP.
• ATP is the immediately usable form of
energy for the cell.
• It is used to drive endergonic
(anabolic/build up) reactions.
ABOUT ATP
• ATP is used up almost as quickly as it is
produced; usually used up within 60
seconds of being formed. ( Yep! Gone
in 60 seconds!)
• Its production is an ongoing process
within body cells.
• It is produced using energy made
available by the catabolism(breakdown)
of organic compounds (usually
glucose).
An ATP molecule
Adenosine Triphosphate (ATP)
Building Blocks of ATP
Adenosine diphosphate (ADP)
Inorganic
phosphate
• Production of ATP is said to be
COUPLED with the breakdown of
glucose. The energy released in one
reaction (breakdown of glucose) is used
to drive the other (build up of ATP)
ATP Formation (synthesis)
Energy
from
glucose
breakdown
?
+
High energy bond
Synthesis: water released
Energy is released from ATP when
the high energy bond of the last
inorganic phosphate is broken. This
reaction is catalysed by an
enzyme called ATPase
The ADP and P can then be reused
to make more ATP
ATP breakdown (hydrolysis)
Energy
released
for
cellular
use
+
High energy bond broken
(Hydrolysis: water required)
Putting it all together
Catabolism of glucose
DRIVES….
Anabolism of ATP
glucose
Catabolism ATP
Anabolism Protein
Cellular Respiration
Energy is released step by step
ADP+Pi ATP ADP+Pi ATP etc, etc ADP+Pi ATP
ATP
Energy
Energy
Energy
ADP+Pi ATP
Energy
ADP+Pi
Energy
glucose
H2O
CO2
CO2
CO2
(½) O2
• Cellular respiration occurs in ALL living
organisms (and indeed all living cells) at
ALL times. It is essential for the
continuation of ALL life.
• Cellular respiration is a general term,
which refers to the sequential break
down of organic compounds by cells, in
order to produce a form of energy that
is immediately usable by body cells,
typically ATP.
• The energy is released from the
chemical bonds of the organic molecule
that is broken down.
• Cellular respiration involves many
different reactions, each controlled by
its own enzyme.
• Cellular respiration usually uses glucose
however fats (fatty acids and glycerol)
and amino acids can also be used.
TWO TYPES OF RESPIRATION
The two types of respiration are:
Aerobic (using oxygen) and
Anaerobic (not using oxygen).
Aerobic Respiration:
• Provides most of the ATP for use in
most eukaryotic cells.
• Generally it is the breakdown of glucose
in the presence of oxygen to provide
energy for ATP production. (ATP is
then used for cellular activity)
• Carbon dioxide and water are produced
as waste in this process
General equation for aerobic
respiration:
C6H12O6
+
Glucose
6O 2
oxygen
6CO2
+
carbon dioxide
6H2O +
water
36 to 38 ATP
energy
Other ways of writing this
36 ADP + 36 pi
C6H12O6
+
6O
36 ATP
2
C6H12O6 + 6O 2 + 36 ADP + 36 pi
6CO2
+
6H2O
6CO2 + 6H2O + 36 ATP
• Some venoms and toxins can uncouple
the reactions of cellular respiration and
ATP formation.
• When this happens extra energy is
released as heat and a fever is
experienced.
• Apart from fever what other symptom
will be experienced? Think ….answer on
next slide
• Since less ATP is formed (energy is
transformed into heat rather than being
used to form as many ATP molecules)
you will feel tired and like you have no
energy!
cytosol
• Mitochrondrion
1 Glycolysis
2. Krebs Cycle
3. Electron Transport
Anaerobic Respiration:
• Occurs in the absence of oxygen.
• Occurs in the cytosol.
• Net production of two ATP molecules
per glucose molecule
• Reduced efficiency, as glucose is not
totally broken down.
• The process is different in the cells of
different organisms due to the different
enzymes present within
1 Glycolysis
• Glucosepyruvatelactate
• Glucosepyruvateethanol and CO2
Anaerobic Respiration in animals cells
Glucose
lactate + energy (2ATP)
C6H12O6
CH3CH(OH)COOH + 2ATP
Anaerobic Respiration in fungi cells
Glucose
2 ethanol + 2 carbon dioxide
+ energy (2APT)
C6H12O6
2CH3CH2OH + 2CO2 +2ATP
Try to complete the summary table
of the two processes and then check
the next slide for the answers.
Comparing Aerobic and
Anaerobic Respiration
Aerobic Respiration
Anaerobic
Respiration
Cytosol
Where does it
occur?
When does it
occur?
Relative speed of
ATP production
Mitochondria
When oxygen is
present
Relatively slow due to
more steps in process
When oxygen is absent
Net ATP Yield ?
36/38
2
What are the
reactants?
What are the
products?
Usually glucose and
oxygen
Carbon dioxide and
water
Glucose only
Relatively fast due to
fewer steps in process
Animal
cells
Lactic
acid
Plant or
fungal cells
Ethanol and
carbon
dioxide