Title: Harvesting the Energy in Food To Make ATP: Cellular Respiration
1Harvesting the Energy in Food To Make
ATPCellular Respiration
- Mr. G-Dizzles Bio Class
- November 2005
2Laws of Matter and Energy
- Law of the Conservation of Matter
- Matter is neither created nor destroyed The
amount of matter in the universe is constant - This is why we must balance chemical equations
- Law of the Conservation of Energy/1st Law of
Thermodynamics - Energy is neither created nor destroyed The
amount of energy in the universe is constant - 2nd Law of Thermodynamics
- Whenever high quality (concentrated) energy is
used to do work, some of the energy is converted
to a lower quality (less-concentrated) form
usually heat - In other words, while the quantity of energy does
not change in the universe (the 1st law of
thermo), the QUALITY does - You can not take low quality energy and recycle
it back into high quality energy!!!
3Laws of Matter and Energy and Their Application
in Daily Life
- How do food chains and food webs demonstrate the
laws of matter and energy? - Only 25 of the energy of gasoline actually
produces motion in a car. Only 5 of the
electricity of a light bulb actually produces
light. - How does the 2nd law explain this?
4Food Chains in Action
5How does a sealed aquarium demonstrate the laws
of matter and energy?
6So Whats Energy Again?
- The ability to do ___________?
- Three main forms of Energy
- Potentialenergy of position or chemical
arrangement - Chemical energy of bonds is a type of PE
- Remember you must add energy to break bonds
(the activation energy) and energy is released
when bonds form - Kineticenergy of motion
- Thermalthink of this as heat energy
7Who can explain the energy conversions going on
here? What are the similarities and differences
between the two scenarios?
FIGURE 7-6
8What are the similarities and difference b/w
Energy Conversions in a car and in a cell?
25 efficient
40 efficient
FIGURE 7-7
9Food As Fuel Lab
- How do you measure how much energy a piece of
food has? - BURN IT! And see how much of a temperature change
you can get from a known amount of water - What are the units of energy in food?
- 1 Calorie The energy needed to raise 1 liter of
water (1 liter1000ml1000g) 1oC - 1 Calorie 1000 calories1Kcal
- 1 can of coke200 calories
- Enough to heat one gram of water by 200,000
degrees Celsius! - What would happen if the cells of our body
released too much energy at once?
10FIGURE 7-5
11Cell Respiration Big Picture
- C6H12O6 6O2? 6CO2 6H20 38 ATP
- This process harvests the potential (chemical)
energy in food (glucose) molecules and converts
it into the potential (chemical) energy of ATP - This process happens in number of enzyme
catalyzed reactions occurring in both the
cytoplasm and mitochondrion of the cell - Think of ATP as a battery molecule it is a
temporary storage place for the energy of the
glucose molecule and can be called upon to
release this energy in just the right amounts to
perform cellular work
12So What is this ATP thing anyway?
- Adenosine Triphosphate
- Ribose sugar attached to 3 phosphate groups
- Potential energy of food is converted into the
potential energy of the bonds of this molecule - Negatively charged phosphates right next to each
other is kinda like a compressed spring - These are very unstable bonds with a lot of
potential energy in them!
13(No Transcript)
14When enzymes break off the last phosphate of the
tail and transfer it to another molecule,
energy is released and made available to do
cellular work
FIGURE 7-9
15FIGURE 7-11
16So What Kind of Work Does ATP Power in the Cell?
FIGURE 7-10
17How does breathing relate to cellular respiration?
FIGURE 7-12
18The Key To Cell Respiration is Falling Electrons
- Glucose is made of Carbon Carbon and Carbon
Hydrogen bonds - During Cellular Respiration, the glucose molecule
is ripped apart and the C-H bonds switch
partners and form new bonds with oxygen instead - C-H is replaced by C-O and H-O bonds
- As electrons fall toward oxygen in the forming
of these new bonds, energy is released - This energy is harvested by the cell and is used
to add a phosphate onto ADP to form ATP
19FIGURE 7-15
20Big Picture of Cellular Respiration
See A Closer Look ONLINE ACTIVITY
FIGURE 7-16
21STAGE IGLYCOLYSISThe Splitting of Sugar
- Where? In the cytoplasm
- Is oxygen used/needed? NO (anaerobic)
- What goes in? Glucose and 2 ATP
- What comes out?
- 4 ATP molecules (net gain of 2why?)
- 2 molecules of pyruvic acid (goes to next stage)
- Energy rich electrons and a hydrogen ion from
glucose are transferred to a carrier molecule
called NAD to form NADH. - This carrier molecule think of it as a taxi
for Hydrogen atoms will eventually give up the
electrons to the ELECTRON TRANSPORT CHAIN and
this will power the making of ATP!
22FIGURE 7-20
23Stage IIKrebs Cycle
- Where? In the matrix of the mitochondria
- Is oxygen used/needed? YES (aerobic)
- What goes in? Pyruvic acid (in the presence of
O2) - What comes out?
- CO2
- NADH/ FADH2
- 2 ATP
- Although some ATP are produced, the main job of
the Krebs Cycle is to provide electrons for the
last stage the ETC - In essence, the Krebs Cycle breaks down the
pyruvic acid molecules into CO2 and takes some of
the pyruvic acids electrons and transfers them
to NAD/FAD
24Krebs Cycle
Dont get bogged down in the details!! What goes
in? What comes out? What is happening in
general?
25Stage IIIElectron Transport/ATP Synthase
- Where? In the inner membrane of the mitochondria
- Is oxygen used/needed? YES (aerobic)
- What goes in? NADH and FADH2
- What comes out?
- 34 ATP are generated
- Oxygen ultimately accepts the electrons at the
end of the ETC and then combines with a few
hydrogen ions to create WATER (H2O) - A series of proteins embedded in the
mitochondrial membrane transfers electrons from
one to another down the chain - With each transfer, the energy level of the
electrons is gradually lowered (like climbing
down stairs!) - The energy from the flow of electrons is used to
pump H ions out of the mitochondrial matrix into
the intermembrane space (from low to high
concentration) - The flow of the H back into the matrix (from
high to low concentration!!!!) provides the
energy that is used to combine ADP and P to
produce ATP.
26Electron Transport Chain Powering The Creation of
ATP
FIGURE 7-19
27FIGURE 7-3