Download Kreb`s Cycle

Cellular Respiration
Chapter 9
Interest Grabber
Section 9-1
•
Feel the Burn
•
Do you like to run, bike, or swim? These all are good ways to exercise. When
you exercise, your body uses oxygen to get energy from glucose,
a six-carbon sugar.
1. How does your body feel at the start of exercise, such as a long, slow
run? How do you feel 1 minute into the run; 10 minutes into the run?
2. What do you think is happening in your cells to cause the changes
in how you feel?
3. Think about running as fast as you can for 100 meters. Could you
keep up this pace for a much longer distance? Explain your answer.
Sunlight powers life
• Autotrophs
– Photosynthesis
– Producers
• Heterotrophs
– Consumers
• Cellular respiration- converts energy into cell
fuel (ATP
Why do living things need food?
• provides living things • source of energy
with the chemical
building blocks they
need to grow and
reproduce.
• Source of raw
materials for making
new molecules
What do cells do with food?
• Cells gradually release energy from
glucose and other food compounds in
the form of ATP.
ATP
• Most of the energy
from cell respiration is
converted into ATP
• ATP is a substance
that powers most cell
activities.
• Energy in phosphate
bonds
Cellular Respiration
• Process that
releases energy by
breaking down
glucose to make
ATP at each stage
Formula
• 3 Steps
– Glycolysis
– Kreb’s cycle
– Electron Transport
Chain
Cellular Respiration
3 stages:
1. Glycolysis –the breaking of glucose into
pyruvate
2. Kreb’s Cycle–pathway which converts
pyruvate
3. Electron Transport Chain- coverts
NADH into ATP
The 3 steps of cellular respiration
1. Glycolysis
2. Kreb’s cycle
3. Electron Transport
Chain
• Each stage captures
some of the
chemical energy
available in food
molecules and uses
it to produce ATP.
Chemical Pathways
Section 9-1
Glucose
Glycolysis
Krebs
cycle
Fermentation
(without oxygen)
Electron
transport
Alcohol or
lactic acid
Glycolysis
• Occurs in
cytoplasm
• Does not require
oxygen
• Net gain of ATP = 2
• Molecule of
glucose is broken in
half to two
pyruvate molecules
(then goes into
mitochondria)
Cellular Respiration
End of Glycolysis
• 90% of the energy
of glucose still has
not been used
• The energy is
stored in the
electrons of pyruvic
acid
Cellular Respiration
Stage Two(Aerobic): Production of ATP
•Krebs Cycle
•reactions that produce
energy-storing
molecules (NADH and
ATP)
•Pyruvate  citric acid
•In mitochondria
• Carbon dioxide given
off
Section 9-2
Figure 9–6 The Krebs
Cycle
Citric Acid
Production
Mitochondrion
Mitochondria
• The matrix where 3carbon pieces that
came from
carbohydrates are
broken down to (CO2
and water)
• The cristae is where
ATP is made
Stage 3- ETC- Electron transport chain
• Hot potato-electrons
• Uses high energy electron to convert
NADH in to ATP
• Oxygen gets the “hot potato” to
make water
Section 9-2
Figure 9–7 Electron Transport
Chain
Electron Transport
Hydrogen Ion Movement
Channel
Mitochondrion
mbrane
ATP synthase
Inner
Membrane
Matrix
ATP Production
Fermentation
(anaerobic)
• When oxygen is not • Two types
present, gylcolysis
– Alcoholic
fermentation
follows this
pathway
– Lactic Acid
Fermentation
(anaerobic)
Alcoholic Fermentation
• Yeasts and other
microorganisms
• Causes bread to rise
• Formula
Lactic Acid Fermentation
• Pyruvic acid can
turn to lactic acid
so gylcolysis can
continue
• Produced in
muscles during
exercise when
oxygen is used up
• Muscles continue
to make ATP
Alcohol Fermentation
• Unicellular
organisms also go
through this process
• Used in the
productions of foods
and beveragescheese, yogurt, sour
cream, pickles,
alcoholic beverages
Summary
Molecule
Role in respiration
C6 H12O6 Broken down in glycolysis = 2 ATP made,
pyruvate
O2
H2O
CO2
Accepts H+ in ETC, aids in making ATP
* Aerobic respiration only
Made in ETC, waste product
Made in Krebs cycle, waste product
Flowchart
Section 9-2
Cellular Respiration
Glucose
(C6H1206)
+
Oxygen
(02)
Glycolysis
Krebs
Cycle
Electron
Transport
Chain
Carbon
Dioxide
(CO2)
+
Water
(H2O)
Review