Download Anaerobic Respiration

Cells Memory Jogger
1.
2.
3.
4.
5.
What is the process called when a phosphate
is added?
ATP stands for ___________ ___________.
What does ‘lysis’ generally mean at the end of
a word?
Which organelle is the ‘powerhouse of a cell’?
What does ‘aerobic’ mean?
Cells Memory Jogger
1.
What is the process called when a phosphate is
added? phosphorylation
2.
Adenosine triphosphate
ATP stands for ___________
___________.
3.
What does ‘lysis’ generally mean at the end of a
word?
4.
to split or break apart
Which organelle is the ‘powerhouse of a cell’?
mitochondria
5.
What does ‘aerobic’ mean? requires oxygen
Respiration
The Chemistry of
Respiration
energy and mitochondria clip
The role of ATP review
► ATP
stores the energy in the third bond
of the molecule
► The
energy is released when that bond is
broken to release the third inorganic
phosphate.
►
Pi= the phosphoric acid
adenosine
P
P
P
ATP
Enzymes
adenosine
P
ADP
P
+
Energy
released
to do work
P
Summary
ATP
ATP
cellular
respiration
cellular
respiration
energy
(out)
energy
(in)
energy
(out)
cell
cell
activities
activities
ADP + Pi
The whole process is an enzyme controlled reaction.
Cell Respiration
► The
process by which food molecules (ex:
glucose) are broken down to produce ATP.
► Takes place in the mitochondria of plants and
animals.
► There are 3 stages of respiration:
1. Glycolysis
2. Krebs Cycle
3. Electron Transport Chain
► Chemical
Equation:
C6H12O6 + 6O2
6CO2 + 6H2O + Energy
breathing
and
respiration
intro. click
16-22
(aerobic
resp.)
Aerobic respiration = respiration with oxygen
Aerobic respiration happens in 3
stages:
Stage 1 – Glycolysis
glyco
glucose
lysis
splitting
2 ATP needed
to start
reaction, 4
ATP are
produced thus
the net gain is
2 ATP from
glycolysis.
In glycolysis, a glucose molecule is broken
down into two molecules of pyruvic acid.
glucose
energy released to
make small
quantity of ATP
(2 molecules)
series of enzyme
controlled reactions
pyruvic acid
Glycolysis does not require oxygen
In both eukaryotes and prokaryotes, this
process occurs in the cytosol of the cell.
The cytosol is the portion of the cytoplasm not contained within
membrane-bound organelles. Cytosol makes up about 70% of
the cell volume and is composed of water, salts and organic
molecules.
Breakdown of Pyruvic acid
The pyruvic acid made in glycolysis
(stage1) still contains a lot of energy
It can only be broken down to
release the rest of the energy in
the presence of oxygen.
Stage 2: Krebs Cycle
► Pyruvic
acid molecules then move into the
mitochondria to begin the next stage of
cellular respiration: the Krebs Cycle.
► During
the Krebs Cycle, pyruvic acid is
broken down into carbon dioxide in a
series of energy-extracting reactions.
► Citric Acid is created in this cycle thus
giving it the nickname Citric Acid cycle.
► Net ATP Production is 2 ATP from the
Krebs Cycle.
Mitochondrial structure
Krebs cycle
takes place in
the matrix.
Stage 2: Krebs Cycle
► The
enzyme involved in this stage is
referred to as acetyl-CoA
► The citric acid is broken down into a 5carbon compound, then into a 4-carbon
compound. Energy is being released along
the way.
► Electron carriers in the form of NADH and
FADH2 are produced, which transport
energized electrons along the electron
transport chain in the mitochondria.
Stage 3: Electron Transport Chain
► The
electron transport chain uses the highenergy electrons from the Krebs Cycle to
convert ADP to ATP.
► Same idea as in photosynthesis: energized
electrons from Citric Acid Cycle are passed
from protein to protein, losing energy as
they go.
► The energy is used to make ATP.
Stage 3: Electron Transport Chain
► Takes
place in the mitochondria in the
cristae or inner membrane.
► Requires oxygen to assist in passing the
electrons from protein to protein.
► Water is formed.
► Net ATP Gain: 32 ATP from the electron
transport chain.
So why do we need oxygen?
►Oxygen
serves as the final electron
acceptor of the electron transport
chain. Therefore, oxygen is essential
for getting rid of low-energy electrons
and hydrogen ions, the wastes of
cellular respiration.
Cell Respiration Summary
► Total
process (Glycolysis, Citric Acid Cycle,
and Electron Transport Chain) produces 36
ATPs.
► All of this is from 1 molecule of glucose!
► This happens in 1 mitochondrion (liver cells
may have 2500 mitochondria each!)
► Cells and organisms require a HUGE amount
of energy!!
Anaerobic Respiration
(in animals)
anaerobic = in the absence of
oxygen
In low oxygen conditions or
during heavy exercise, when not
enough oxygen can be supplied,
muscle cells swap to anaerobic
respiration
Lactic Acid Fermentation
► Glycolysis
still takes place but is followed by
this type of fermentation.
► Fermentation:
releases energy from food
molecules in the absence of oxygen
glucose
glycolysis still
happens as it does
not require oxygen
pyruvic acid
in absence of
oxygen pyruvic
acid is turned
into lactic acid.
lactic acid
2 ADP + 2 Pi
2 ATP
A build up of lactic acid produces muscle
fatigue.
Muscle fatigue makes muscles ache and
contract less powerfully.
A recovery period is needed. During
this time more oxygen is taken in to
convert the lactic acid back into pyruvic
acid again.
2 ATP’s are produced.
Summary
glucose
pyruvic acid
oxygen debt
e.g. during hard
exercise
lactic acid
oxygen debt
repaid during
recovery time
Anaerobic Respiration
in plants
The same process occurs in
plants and yeast in low
oxygen conditions, e.g.
muddy, flooded soils.
Alcoholic Fermentation
► Used
most commonly by yeast.
► CO2 + ethyl alcohol are produced from 2
pyruvic acids.
► 2 ATPs are produced
► These
processes (fermentation) are not
ideal, because they are not as efficient at
producing energy, and so they occur in
lower organisms, or under distress.
glucose
2 ADP + 2 Pi
glycolysis still
happens, producing
2 ATP molecules
2 ATP
pyruvic acid
This time in absence of
oxygen, pyruvic acid is
turned into carbon
dioxide and ethanol
This is irreversible
ethanol + carbon dioxide
Energy & Exercise
► Quick
energy – Lactic Acid fermentation is
used to get quick energy and gives off lactic
acid as a by product, thus the muscle pain.
► Long-Term Energy – Use cellular respiration
to produce energy. Exercising or activities
that last for at least 15 to 20 minutes. Best
form for weight control.
Comparison of aerobic and
anaerobic respiration
Aerobic respiration
Anaerobic Respiration
in animals
in plants and yeast
Oxygen required?
yes
no
no
Glycolysis occurs
yes
yes
yes
ATP yield
36ATP
2ATP
2ATP
Glucose completely broken
down?
yes
no
no
End products
Carbon
Lactic acid
dioxide
and water
Ethanol and
carbon
dioxide
Comparing Photosynthesis &
Respiration
Photosynthesis
Cellular
Respiration
Function
Energy Storage
Location
Chloroplasts
Energy
Release
Mitochondria
Reactants
CO2 and H2O
Products
C6H12O6 and O2
C6H12O6 and
O2
CO2 and H2O
Equation
6CO2 + 6H2O 
C6H12O6 + 6O2
C6H12O6 + 6O2
6CO2 + 6H2O
Cool Websites
► SongYouTube
- cellular respiration on Cellular
Respiration
http://www.youtube.com/watch?v=kPNVRDAx7Jc
► http://www.youtube.com/watch?v=fmyby8zWeSU
&mode=related&search=
► http://www.phschool.com/science/biology_place/l
abbench/lab5/cellular.html
► Movie on Cellular Respiration