Transcript Cellular Respiration

Cellular Respiration
Biology G/T
Why do we need Cellular
Respiration?
If we released all of the
energy from glucose all at
once, so much heat would be
released that we would
explode or at least denature
all of our proteins.
Cellular Respiration Overview
Taking the high energy electrons out of
sugar and releasing the energy from
the electrons in small steps and using
that energy to make ATP
After the energy is released from the
electrons, they are returned along
with the protons (H+) to oxygen
making water
ATP
ATP
Release Energy
To do work
From
glucose
ADP
Use Energy in ATP to do work
Work in living things:

Intra-cellular Transport

Chemical reactions

Muscle Contraction

Active Transport, Endo and Exocytosis
Mitochondria Structure
e.t.c.
Enzymes (Krebs),
DNA, RNA,
ribosomes
Overview of the reactions
Overview of the reactions
Glycolysis
With
oxygen
Chemical reaction to make
acetate (mitochontrial
matrix)
Aerobic
Krebs cycle (mitochondrial
matrix)
Cytoplasm
Anaerobic
Without oxygen
Electron Transport Chain
(inner-mitochondrial
membrane)
38
Fermentation
Cytoplasm
Still Anaerobic
2
ATP
Glycolysis: first step of
cellular respiration
Glucose
Pyruvate
Pyruvate
2 ATP
2 carriers with H and it’s
high energy electrons
Fermentation
Pyruvates
(2 of them)
Yeast Cell
Alcohol +
CO2
Animal Cell
Lactic
Acid
All are waste products, so most of the energy
stored in the sugar ends up not getting used by
the organism
Anerobic Activities
No activity can be totally anaerobic and be
compatible with life – it just means you can’t get
enough Oxygen to stay totally aerobic (your
need for ATP is greater than you can supply the
oxygen for)
Anaerobic activities include anything that makes
you breathe excessively heavy – sign you’re not
getting enough oxygen
Sprinting, swimming really fast, biking really fast,
etc., lifting really heavy weights
You will make lactic acid and run out of ATP –
can’t keep going for very long
You only make 2 ATP vs. 38 ATP when you do
anaerobic CR
Making Wine and Bread
Yeast using the sugar provided by grapes or
flour and added sugar to do cellular respiration
Sugar diffuses into yeast cells, if not enough
oxygen, do some aerobic and some anaerobic
respiration
As a result of anaerobic, they make alcohol and
CO2
In wine, CO2 evaporates and left with alcohol in
the grape juice
In bread, baking the bread makes the CO2 and
alcohol evaporate leaving behind holes where
CO2 was making the bread fluffy
No Name Step (first step in
mitochondrial matrix – aerobic)
CO2 released and H
with its high energy
electrons get put on a
carrier
Pyruvate
Acetate (still contains
most of high energy electrons)
+ Coenzyme
A
Acetyl CoA
The Kreb’s Cycle:
Series of Chemical Reactions in
Mitochondrial Matrix
Acetate gets broken down to 2 CO2 and
all 4 of the H with their high ENERGY
electrons get put onto carriers X2
2 ATP’s are made
For each glucose, there are 2 acetates!
Electron Transport Chain
Located in the inner mitochondrial
membrane
Electron Transport Chain – series of
carriers – each one more electronegative
(attracted to electrons) than the previous
one
As the electrons are passed from carrier to
carrier – they are pulled closer to the
atomic nucleus which causes them to lose
energy
The energy is lost a little bit at a time
Steps of the E.T.C.
STEP 1: the electron carriers that picked up
electrons in glycolysis, no name step, and the
Kreb’s cycle pass their electrons to the first
molecule of the electron transport chain
STEP 2: with each successive pass to other
carriers, the electrons lose energy
STEP 3: The energy lost by the electrons is
used to make ATP’s (34/ glucose)
STEP 4: The Hydrogens and their electrons
which now have the normal amount of energy
(lost the extra absorbed by the sun during the
e.t.c) combine with oxygen to form water. There
isn’t a big energy change all at once so there is
no explosion just the loss of a reasonable
amount of heat
Summary
Break the sugar apart back into CO2 and
H which combine with O to make H2O
The excess energy stored in the electrons
of H is slowly released and used to make
ATP before they combine with the O
Therefore, the energy that came from the
sun and was stored in the organic
molecule sugar, is now temporarily stored
in ATP until the energy is used to transfer
the last phosphate to a motor protein,
muscle protein, or substrate to do work
How to use Fat and Protein for
Energy
Each fatty acid is broken up and
rearranged to form many acetates which
enter the Kreb’s Cycle
Amino acids contain very few C-H bonds
but the amino and acid groups can be
clipped off, and the rest can also be
rearranged to enter glycolysis or the
Kreb’s Cycle