Download Popeye knew what he was doing!

Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Today’s
reference:
Sec 5.3
Methane
All these products are the result of cellular respiration! There
do3 these
things
have
in common?
areWhat
actually
different
types of
respiration
– let’s take a look!
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Cellular Respiration – What we Know:
•Cells convert the energy stored in glucose to ATP.
•The process of cellular respiration oxidizes glucose to
form CO2 and H2O, and the released energy is stored as
ATP.
•ATP is then used as an energy source for most cell
processes (muscle contraction, active transport, etc.).
C6H12O6(aq)+ 6O2(g)
6H2O(l) + 6CO2(g) + Energy
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Cellular Respiration – What we don’t know:
• The three types of respiration are as follows:
1. Aerobic respiration
• Occurs in the presence of oxygen, and the most
common form in plants and animals because it yields
the most energy.
2. Anaerobic respiration
• Occurs without oxygen, and is seen in some types of
bacteria.
3. Fermentation
• A much less efficient form of anaerobic respiration that
occurs in fatigued muscle cells and yeast involved in
bread and wine making.
Overview
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
The three types of respiration:
• The differences between the types of respiration are:
1. The final end product.
2. The amount of ATP produced.
• The similarity between the types of respiration is:
1. They all begin with the same process – glycolysis.
Let’s focus on the details of aerobic respiration,
beginning with glycolysis.
Later, we will see how fermentation and anaerobic
respiration differ.
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Aerobic Respiration – Overview
• There are four main stages in aerobic cellular respiration:
1. Glycolysis – Oxidation of glucose into pyruvate that occurs
in the cytoplasm of the cell.
2. Kreb’s cycle preparation – Pyruvate is used to form acetylCoA in the matrix of the mitochondria.
3. Kreb’s cycle – Energy is stored in reducing power of NADH
and FADH2 within the matrix of the mitochondria.
4. Electron Transport Chain – Large amount of ATP is
produced using the ETC embedded in the inner membrane
of the mitochondria.
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Backtrack: Structure of the Mitochondria
•Outer membrane surrounds
mitochondria.
•Inner membrane is highly folded and
is location of ETC.
•Cristae is the term used for the long
tube-like folds of the inner membrane.
•Matrix is the gel-like interior
surrounded by the inner membrane.
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Stage One – Glycolysis (in CYTOPLASM):
• Glucose is broken down and eventually forms two
molecules of pyruvate.
• During the steps it takes to do this, 2 ATP molecules
and 2 NADH molecules are formed.
Glucose
2 ADP + 2P
2 NAD+
Intermediates
Intermediates
2 ATP
2 NADH
Pyruvate
Glucose + 2ADP + 2P + 2NAD+
Pyruvate
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Stage Two – Preparing for Kreb’s Cycle:
• Pyruvate enters matrix of mitochondria.
• Pyruvate loses a carbon atom and binds with coenzyme A (CoA)
to form acetyl CoA.
• Carbon dioxide is produced as a byproduct.
NAD+
Pyruvate
+
CoA
2Pyruvate + 2CoA + 2NAD+
NADH
Acetyl CoA
+
CO2
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Stage Three – Kreb’s Cycle (In Matrix):
•Oxidation of carbon molecules forms
ATP, NADH, and FADH. CO2 is a byproduct.
•The net result using 2 acetyl-CoA
molecules is as follows:
2 acetyl CoA
4 CO2
2 ATP
6 NADH
2 FADH2
Question: The cellular respiration
equation says 6 carbon dioxide
molecules are produced, but only four
are shown from the Kreb’s cycle. Where
do the other 2 come from?
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Stage Four – ETC (Inner Membrane):
•The NADH and FADH2 produced in steps 2 and 3 now enter
the ETC found in the inner membrane.
•The 2 NADH produced in step 1 is also shuttled in, but at the
cost of 2 ATP molecules.
•The NADH and FADH2 donate their electrons to the ETC to
generate ATP in a process similar to the ETC in chloroplasts.
(know how this works, but don’t worry about labeling cytochromes)
•For every NADH that enters the ETC, 3 ATP are formed.
•For every FADH2 that enters the ETC, 2 ATP are formed.
•Note that oxygen is the final electron acceptor, producing
H20!
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Cellular Respiration – Where did it all come from:
•Let’s take a look again at the four stages and where
they occur.
•Let’s take a look at what stage of aerobic respiration
these reactants and products are involved (use your
notes!)
C6H12O6(aq)+ 6O2(g)
6H2O(g) + 6CO2(g) + Energy
So what happens to all the oxygen we breathe in?
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Can You Do the Math?:
•Remember that:
Glycolysis
2 ATP
1 NADH = 3 ATP and 1 FADH2 = 2 ATP
2 NADH
6 ATP
How many ATP molecules do you
think are formed
in the four stages of
SHUTTLE
-2 ATP
aerobic respiration? Don’t forget 2 ATP molecules are used to shuttle
Pyruvate
CoA to the2 mitochondria!
NADH
6 ATP
NADH
from theAcetyl
cytoplasm
Kreb’s Cycle
6 NADH
18 ATP
2 FADH2
C6H12O6(aq)+ 6O2(g)
4 ATP
36 ATP
6H2O(g) + 6CO2(g) + 36 ATP
Blackened areas of the Popeye
beached remains
of a grey
whaledoing!
show
knew what
he was
hydrogen sulfide build up produced by anaerobic bacteria in the
Photosynthesis & Cellular Respiration
colon.
Anaerobic respiration
• Occurs without oxygen, and is seen in some types of
prokaryotes (species in the Bacteria & Archea domains).
• These prokaryotes live in anoxic environments (marshy
swaps, your colon).
• The main difference in anaerobic respiration is that oxygen
is not the final electron acceptor at the end of the ETC. It is
usually an inorganic chemical such sulfate or carbon
dioxide.
• Common byproducts are methane, nitrogen, or sulfur.
• Take a look at the effects of anaerobic bacteria….
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Fermentation
• Occurs without oxygen, and is seen in some types of
bacteria, yeast, and fatigued muscle cells.
• Fermentation occurs only in the cytoplasm (no ETC
involved). After glycolysis, 1 or 2 reactions occur to reduce
pyruvate to another compound.
• Fermentation is less effective than other forms of
respiration, because the only ATP generated comes from
glycolysis.
• Two common byproducts are lactate (lactic acid), as is
seen in our muscle cells, and ethanol, as is seen in
brewer’s yeast. (Take a look at figures 5.21 and 5.22 on
pages 190-191 in your textbook for pathways).
Lab Time!
Alcohol Fermentation
Lactic Acid Build up
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
Partner Project – Metabolic Toxins
•In the 1930’s, dinitrophenol (DNP) was used as a diet pill.
•DNP affects chemiosmosis by disrupting the hydrogen
ion concentration gradient, thus interfering with ATP
production.
•Since the mitochondria is not producing enough ATP, the
body would rapidly oxidize (metabolize) carbohydrates
and fats, leading to rapid weight loss.
• Low ATP production, however, also lead to very poor
health and even death.
• DNP was pulled from the shelves as a diet pill.
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
HOWEVER
Partner Project – Metabolic
Toxins
•In
the 1930’s,
dinitrophenol (DNP)
was used
diet pill.
Some
bodybuilders,
at great
risk as
toatheir
•DNP
affects
chemiosmosis
by disrupting
the hydrogen
health,
will
still use DNP
prior to
ion concentration gradient, thus interfering with ATP
competitions.
production.
Whythe
is mitochondria
this unsafe?
Are
there other
•Since
is not
producing
enough ATP, the
body
would rapidly
oxidize
(metabolize)
metabolic
toxins,
and
do theycarbohydrates
do the same
and fats, leading to rapid weight loss.
thing?
• Low ATP production, however, also lead to very poor
health and even death.
• DNP was pulled from the shelves as a diet pill.
Popeye knew what he was doing!
Photosynthesis & Cellular Respiration
An uncoupler is a lipidsoluble weak acid that
carries hydrogen ions
across the inner
membrane without use of
ATP synthase. Thus, the
movement of H ions is not
generating the energy to
create ATP.