Download Cellular Respiration #2

Chapters 7 - Cellular Respiration
OBJECTIVES: STUDENTS WILL BE ABLE TO…
1.
2.
3.
4.
5.
6.
Identify the two major steps of cellular respiration.
Describe the major events in glycolysis.
Compare lactic acid fermentation with alcoholic fermentation.
Relate aerobic respiration to the structure of a mitochondrion.
Summarize the events of the Krebs cycle.
Contrast the roles of glycolysis and aerobic respiration in cellular
respiration.
ADDITIONAL BIG IDEA:
7.
Understand the main pathways by
which energy and carbon atoms enters
food chains and passes from organism
to organism and/or back into the
environment.
KEY TERMS:
Cellular respiration
Glycolysis
Pyruvic acid
NADH
NAD+
Anaerobic respiration
Fermentation
Lactic acid fermentation
Alcoholic fermentation
Aerobic respiration
Mitochondrial matrix
Acetyl CoA
Krebs cycle
Helpful terms
Kilocalorie
FAD
Oxaloacetic acid
Citric acid
Cha 7: Cellular Respiration
How Cells Harvest Chemical Energy
Cellular Respiration (Exergonic):
Reaction:
A. Breathing supplies O2 to our cells and removes CO2
o What is the connection between breathing and cellular respiration?
o Why are sweating and other body-cooling mechanisms necessary during
vigorous exercise?
o If walking 3 mph burns 158 Calories per hour, how long would it take to
“burn off” the equivalent of an extra slice of pizza (475 Cal)? How far is
that (in miles)?
o The most effective exercise for losing weight is:
pushing away from the table!
B. Carbon and Energy
o Aerobic respiration (with oxygen) is the main pathway for energy release
from carbohydrate to ATP.
o The carbons in glucose are released back to the atmosphere as CO2. The
carbon atoms can be reused in photosynthesis.
o The energy stored in the glucose is used to produce ATP. The energy in
the ATP is used to do cellular work and then is released as heat energy.
The energy cannot be reused. It is lost to the system.
Cellular Respiration Background
1.
State the first and second Laws of Thermodynamics. How do they apply to living systems?
2.
What is energy?
What is chemical energy?
3.
What happens in exergonic reactions?
What happens in endergonic reactions?
4.
What is cellular respiration and why is it so important to living organisms?
5.
What is ATP and what is its function in all cells?
6.
Compared to ATP, is ADP energy rich or energy poor?
7.
Draw, label and explain the ATP/ADP Cycle.
Glycolysis
Stored energy in a glucose molecule cannot be released all at once. Instead, the
cell takes glucose through a series of chemical reactions in an effort to slowly release its
energy.
The first step of the respiration is called: _________________________
I.
II.
Glycolysis means _________________________
a.
It takes place where in the cell? _________________________
b.
It does not need _________________________ to carry out its reactions.
c.
What term refers to a lack of this? _________________________
d.
What forms of life use glycolysis? _________________________
Preparatory phase (energy investment)
a.
III.
In order to begin the process, the cell needs some starting materials. They are:

fuel in the form of ____________

ATP molecules (how many? ________)

the hydrogen shuttle molecule NAD+ (is this compound low or high energy?)
b.
Since energy is added, this step of the reaction is _________________________.
c.
Each 6-C molecule is split into two very reactive 3-C molecules of _________________.
d.
Summarize what happens in the preparatory phase of glycolysis:
Energy Payoff Phase
a.
Each of these two intermediate molecules will undergo a series of chemical reactions
producing what?
i. How many ATP:
ii. How many pyruvic acid:
iii. How many NADH:
(is this compound low or high
energy?)
b. Since energy is released, this step of the reaction is _________________________.
IV.
For each glucose molecule processed, what are the net molecular products of glycolysis?
a.
b.
The net gain of two ATP molecules from glycolysis accounts for only 5% of the energy
that a cell can harvest from a glucose molecule. The two NADH molecules generated
account for another 16%, but their stored energy is not available for use in the absence of
O2. Some organisms (yeast, bacteria, etc.) can satisfy their energy needs with the ATP
produced by glycolysis alone. Most organisms, however, have far higher energy demands
and cannot live by glycolysis alone.
Following glycolysis, what might happen to the pyruvic acid molecules?
Cellular Respiration #2
1. Respiration always begins with what stage?
2. Which kind of respiration results in the
most efficient use of the energy stored in
glucose?
3. Why must all organisms carry on some
form of cellular respiration?
4. NAD and FAD are both hydrogen
acceptors. Do they gain or lose energy
when accepting hydrogen? Explain.
5. What is the net gain in ATP from one
glucose molecule in aerobic respiration?
6. What is the net gain in ATP from one
glucose molecule in anaerobic respiration?
7. What is the function of the Krebs Cycle?
8. What happens to most of the energy stored
in glucose in aerobic respiration?
9. In anaerobic respiration?
10. Draw and explain how muscle cells
produce lactic acid.
11. What would happen if the energy in
glucose were released all at once instead of
in a series of small steps?
12. Do you think yeast cells would grow more
rapidly when carrying out fermentation or
aerobic respiration? Support your answer.
13. Victims of a heart attack often have small
amounts of lactic acid in the blood leaving
the heart. What does this suggest as a
possible cause for heart attacks?
14. Compounds that participate in energy
changes in living cells have been compared
to “charged batteries” and “discharged
batteries”.
o Which cellular compound(s) would
the charged batteries represent?
o The discharged batteries?
15. How does the discharged battery get
“charged up” again?
o
16. Compare and contrast aerobic and anaerobic respiration using the following characteristics:
Characteristic
Starting material
Stages involved
End products
Energy production (# of ATPs)
Aerobic respiration
Anaerobic respiration
Aerobic Respiration pathway
During glycolysis, glucose is converted to two molecules of pyruvic acid. Two
ATP were required to start the reaction, but glycolysis produces four ATP, resulting in a
net gain of two ATP for glycolysis (-2+4=+2).
What happens next depends on whether or not oxygen is present. If O2 is present,
the aerobic respiration pathway is followed. If not, then anaerobic respiration occurs.
I.
The final molecule produced by glycolysis is _________________________.
II.
If there is ___________ present in the cell, these molecules will be changed into a
compound called _________________________ before they are allowed to enter the
organelle called the _________________________.
III.
During this change from _____________________ to _____________________, one
molecule of NADH and one molecule of CO2 are produced.
a.
Since ________ pyruvates are produced from each glucose molecule,
________ NADH and ________ CO2 are produced.
b.
IV.
Each NADH has enough stored energy to produce ___3____ ATP molecules.
Now the Acetyl coA will enter the mitochondrion and go to the center part of it called the
_________________________. Here the _________________________ cycle will
begin. This cycle contains ________ steps or chemical reactions. (Only the 2-C acetyl part of
acetyl coA participates in the cycle. The coenzyme A splits off and is recycled.)
a.
Each turn of the cycle will produce ________ ATP, ________ NADH, and
________ FADH2.
b.
Since there are two Acetyl coA produced per glucose, the total amount of ATP is
________, NADH is ________, and FADH2 is ________.
V.
Think: So far, from glycolysis and the Krebs cycle, how many ATP, NADH, and FADH 2
have been produced?
The Mitochondria
o Two outer membranes.
o Space between is the intermembrane space.
o Chamber inside the inner membrane is the matrix.
o The inner membrane is folded into cristae.
VI.
The final stage in aerobic respiration is called __Electron Transport Chain and
Chemiosmosis__. From the Krebs cycle, all of the NADH and FADH2 leaves the matrix
and enter a series of proteins embedded in the __inner membrane ___ of the
mitochondrion. The folds (__cristae___) of this membrane enlarge its __surface area __,
providing space for many copies of the ___electron transport chain __ and many ATP
synthase complexes.
a.
In the mitochondrial matrix: NADH (high energy) becomes ___NAD+ (low energy). This is an
exergonic reaction.
b.
That energy is coupled with the next endergonic reaction: Hydrogen is actively pushed from the matrix
to the ___intermembrane space ___.
c.
The electron transport chain accepts electrons and shuttles them through the chain to the final electron
acceptor __oxygen ___, which combines with two electrons and two hydrogen ions to make __water_.
d.
The electron transport chain, which received energy from the NADH, moved hydrogen against the
concentration gradient. The hydrogen, now in the intermembrane space, then flows through a channel
(___ATP synthase ___) by facilitated diffusion. Thus, the energy from the NADH is ultimately
transferred to ATP in the mitochondria through the ETS.
scratch work:
Glycolysis (substrate-level phosphorylation)
o
investment
o
o
ATP produced
o
o
2 NADH produced
o
add energy below
o
add energy below
Pyruvate to Acetyl coA
o
2 NADH produced
• Krebs Cycle (substrate-level phosphorylation)
• ETS and Chemiosmosis
(chemiosmotic phosphorylation)
o
transport of NADH from cytoplasm to
o
o
uses 0 to 2 ATP
(investment varies)
mitochondria
o
NADH produced in stage 1
o
_____ x 3 ATP =
o
NADH produced in stage 2
o
_____ x 3 ATP =
o
NADH produced in Krebs cycle
o
_____ x 3 ATP =
o
FADH2 produced
o
_____ x 2 ATP =
Total ATP from aerobic respiration
Total ATP Produced:
Aerobic Pathway
In the presence of oxygen
Acetyl coA
Anaerobic Pathway
If no oxygen is present
Alcoholic Fermentation
o ______________
o ______________
In yeast
Lactic Acid Fermentation
o ______________
In some _______and in ________ cells
Anaerobic respiration
o ____________
Aerobic pathway yields 36-38 ATP
Anaerobic pathway yields 2 ATP
Location:
Electron Transport Chain
ETC
Location:
Glycolysis