Download Cellular Respiration Notes

A. Cellular Respiration
(pg. 220)
a) Respiration is the process by which cells obtain energy
from glucose.
i.
It’s during respiration that cells break down food molecules
(carbohydrates) to release the energy that they contain.
ii.
A calorie is the amount of energy needed to raise the
temperature of water 1 degree
b) All living things carry out cellular respiration.
c) Begins with Glycolysis (splitting glucose) releases a
small amount of energy
a) If oxygen is present glycolysis leads to two other
pathways, if no oxygen it leads to a different pathway.
b) Requires some ATP to start
B. Types of Glycolysis
a) Glycolysis in the presence of oxygen leads to
cellular respiration
i.
Cellular Respiration is a 3 stage process
1.
Glycolysis
2.
Krebs cycle
3.
Electron transport chain
b) Glycolysis without oxygen leads to
fermentation
a) Cells convert NADH into NAD+
b) Because fermentation happens without oxygen
it is called an anaerobic process
c)
What kinds of yummy foods ferment?
C. Fermentation
a) Fermentation provides energy for cells without using
oxygen while breaking down food. However, the
amount of energy released is much lower for
fermentation than for respiration.
b) There are two types of fermentation:
i.
Alcoholic fermentation is used by some single celled
organisms. This is called alcoholic fermentation because
alcohol is one of the products produced. (example:
yeast)
http://viewpure.com/dfzYSi6UzaQ?start=0&end=0
https://youtu.be/xClXKMhcFr0
i.
Lactic Acid fermentation takes place in your muscles.
When you are running you cannot breathe in enough
oxygen to supply your muscle cells with oxygen as
quickly as they are using it. Your cells use fermentation
for the energy that they need, one product of this
fermentation is lactic acid and it creates soreness and
weakness in your muscles.
ii.
When would Fermentation be mechanically
advantageous?
D. Different Stages of Cellular
Respiration
Stage 3
a) Respiration is a three stage process:
i.
The first stage is glycolysis, this takes
place outside the mitochondria
1.
This is the process in which one
molecule of glucose is broken in half,
producing 2 molecules of pyruvic acid
(pyruvate), a 3-carbon molecule. Does
this sound familiar?
2.
Uses 2 ATP and yields 4 ATP for a total
of 2 ATP
3.
Uses 2 NAD+ and yields 2 NADH
(these go the electron transport chain)
Stage 1
Stage 2
i.
The second stage is the Krebs cycle
(aka the citric acid cycle), this takes
place inside the mitochondria
1. Named after Hans Krebs who
demonstrated its existence in 1937
2. Pyruvic acid is broken down into CO2 in a
series of energy-extracting reactions
3. 3-C pyruvic acid enters the Krebs cycle
where a C is removed and makes CO2,
NAD+ is turned into NADH and
Coenzyme A is added to the 2 remaining
C to become acetyl-CoA it then adds
itself to a 4-C forming citric acid
4. Citric acid is then broken down into a 5-C
compound and then to a 4-C compound,
during this 2 more CO2 are released, the
e- are joined to NAD+ & FAD to make
NADH & FADH2. One molecule of ATP is
created.
5. 1 pyruvic acid nets 4 NADH, 1FADH2,
AND 1 ATP (*the purpose of NADH and
FADH2 is to carry electrons)
ii. The third stage is the electron transport chain, this
takes place in the inner membrane of the mitochondria
(what does this remind you of…?)
1. Uses high energy e- from the Krebs cycle (NADH & FADH2)
to convert ADP into ATP
2. Combines H+ to oxygen to create water (byproduct)
3. The H+ cause a charge difference between the inside &
outside of the mitochondria, the H+ go through the ATP
synthase and help the ADP to grab another phosphate to
make ATP
4. Uses NADH & FADH2 to turn 3 ADP into 3 ATP
iii. Total for Cellular Respiration =
36 ATP,
10 NADH,
&
2 FADH2
E. Raw Materials & Products
a) The raw materials of respiration are glucose and oxygen
and the products of respiration are water and carbon
dioxide, these materials and products move into and out
of the cell through the process of diffusion (a good
example of this is yeast).
i.
Oxygen is taken into the body when you inhale
ii.
Carbon dioxide and water are released when you exhale
C6H12O6 + 6O2
6CO2 + 6H2O + energy
Reading and Questions
Page 221-225: 1-6
In science notebook
with seat partners
Discussion questions:
 Is it better to be a photosynthesizer or a consumer?
 When would it be beneficial to go through fermentation
instead of cellular respiration?