Download Chapter 9 (Jan 27-29)

Chapter 9 Intro: An Overview of Carbohydrates
(Ch. 5)
1.
What are carbohydrates & what are they made of?
–
–
Sugars
Made of monosaccharides
•
•
•
•
CH20
Sugars end in -ose
Nutrient for cells
Carbon skeleton is used for other organic molecules
Figure 5.3 Examples of monosaccharides
Triose sugars Pentose sugars
(C3H6O3)
(C5H10O5)
H
O
H
Aldoses
C
O
H
O
C
C
OH
H
C
OH
H
C
OH
H
C
OH
H
C
OH
HO
C
H
C
OH
H
H
C
OH
H
H
H
H
C
H
C
OH
H
HO
C
H
C
OH
HO
C
H
H
C
OH
H
C
OH
H
C
OH
H
C
OH
H
H
Glucose
Galactose
H
C OH
H
C
O
H
C OH
H
C OH
C
O
O
C OH
H
C OH
HO
H
H
C OH
H
C OH
Dihydroxyacetone
H
C OH
H
C OH
H
H
C OH
H
Ribulose
O
C
H
Ribose
Ketoses
H
C
Glyceraldehyde
Figure 5.3
Hexose sugars
(C6H12O6)
C H
H
Fructose
Figure 5.4 Linear & ring forms of glucose
O
H
1C
H
HO
2
3
C
6CH
OH
C
H
H
C
5
5C
H
H
4
H
2OH
6
C
H
OH
4C
OH
OH
OH
O
3
C
H
2C
2OH
5C
H
H
OH
C
6CH
O
H
H
4C
1C
CH2OH
O
OH
H
OH
3C
6
H
1C
H
2C
4
HO
H
OH
3
OH
H
H
1
2
OH
OH
H
H
O
5
OH
OH
H
Figure 5.4 (a) Linear and ring forms. Chemical equilibrium between the linear and ring
structures greatly favors the formation of rings. To form the glucose ring,
carbon 1 bonds to the oxygen attached to carbon 5.
Chapter 5 The Structure and Function of Macromolecules
1.
2.
What are carbohydrates & what are they made of?
How are monomers added together to form complex carbs?
(a) Dehydration reaction
in the synthesis of
maltose. The bonding
of two glucose units
forms maltose. The
glycosidic link joins
the number 1 carbon
of one glucose to the
number 4 carbon of
the second glucose.
Joining the glucose
monomers in a
different way would
result in a different
disaccharide.
CH2OH
CH2OH
H
O
H
OH H
OH
HO
H
H
H
HO
O
H
OH
H
OH
H
CH2OH
H
OHOH
H
O
H
OH H
HO
H
1–4
1 glycosidic
linkage
H
4
O
H
OH H
H
OH
O
H
OH
CH2OH
H
OH
OH
H2O
Glucose
Glucose
CH2OH
H
(b) Dehydration reaction
in the synthesis of
HO
sucrose. Sucrose is
a disaccharide formed
from glucose and fructose.
Notice that fructose,
though a hexose like
glucose, forms a
five-sided ring.
O
H
OH
H
H
CH2OH
H
OH
HO
CH2OH
O
H
H
H
HO
CH2OH
OH
OH
Maltose
H
O
H
OH
H
1–2
H
glycosidic
1
linkage
Fructose
2
H
H
CH2OH
OH H
OH
Sucrose
H
HO
O
HO
H2O
Glucose
CH2OH
O
Chapter 5 The Structure and Function of Macromolecules
1.
2.
3.
What are carbohydrates & what are they made of?
How are monomers added to carbs?
What are polysaccharides used for?
–
Energy storage
•
•
–
Starch – plants
Glycogen – animals
Structural support
•
•
Cellulose
Chitin
Chapter 5 The Structure and Function of Macromolecules
H
OH
CH2OH
O OH
H
OH H
H
H
NH
C
O
CH3
(a) The structure of the
chitin monomer.
(b) Chitin forms the exoskeleton
of arthropods. This cicada
is molting, shedding its old
exoskeleton and emerging
in adult form.
(c) Chitin is used to make a
strong and flexible surgical
thread that decomposes after
the wound or incision heals.
Chapter 5 The Structure and Function of Macromolecules
Chloroplast
Starch
Mitochondria
Giycogen granules
0.5 m
1 m
Amylose
Amylopectin
(a) Starch: a plant polysaccharide
Glycogen
(b) Glycogen: an animal polysaccharide
H
H
4
CH2O
H
O
H
OH H
H
OH
HO
H
OH
 glucose
(a)
O
CH2O
H
O
H
OH H
C
H
C
OH
H
HO
C
H
4
H
C
OH
H
C
OH
H
C
OH
OH
1
HO
H
H
OH
 glucose
 and  glucose
ring structures
CH2O
H
O
CH2O
H
O
HO
4
1
OH
O
CH2O
H
O
HO
(c) Cellulose: 1– 4 linkage
of  glucose monomers
1
OH
4
OH
O
CH2O
H
1
OH
O
4
OH
O
OH
OH
O
OH
CH2O
H
O
O
1
OH
OH
OH
O
OH
4
O
OH
OH
(b) Starch: 1– 4 linkage of
 glucose monomers
1
OH
CH2O
H
O
CH2O
H
O
OH
O
CH2O
H
OH
6. Why do we poop corn? (*sorry for the visual)
Chapter 5 The Structure and Function of Macromolecules
Starch
Cellulose
Cow
can digest cellulose well;
no need to eat other sugars
Gorilla
can’t digest cellulose well;
must add another sugar
source, like fruit to diet
Helpful bacteria
• How can herbivores digest cellulose so well?
– BACTERIA live in their digestive systems & help digest
cellulose-rich (grass) meals
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
Why is respiration important?
-
Consumption of food & oxygen to produce CO2, water & energy
C6H12O6 + 6O2  6CO2 + 6H2O + energy (ATP + heat)
Light energy
ECOSYSTEM
CO2 + H2O
Photosynthesis
in chloroplasts
Organic
+ O2
Cellular
molecules
respiration
in mitochondria
ATP
powers most cellular work
Heat
energy
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
Why is respiration important?
-
Consumption of food & oxygen to produce CO2, water & energy
C6H12O6 + 6O2  6CO2 + 6H2O + energy (ATP + heat)
Exergonic (releases lots of energy… -686 kcal/mol)
All foods can be metabolized as fuel (carbs, proteins, fats)
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
Why is respiration important?
What are redox rxns?
-
Reduction & oxidation
LEO says GER
Loss of Electrons – Oxidation : Gain of Electrons – Reduction
Hint: electrons move with H atoms…H = e- + H+
┌----oxidation-----┐
C6H12O6 + 6O2  6CO2 + 6H2O + energy (ATP + heat)
└----reduction----┘
ENERGY COUPLING!!!
(Oxidation is exergonic…reduction is endergonic)
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
-
Glycolysis
Citric Acid Cycle (Krebs Cycle)
Oxidative Phosphorylation
-
Electron Transport Chain (ETC)
Chemiosmosis
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
Electrons
carried
via NADH
Electrons carried
via NADH and
FADH2
Citric
acid
cycle
Glycolysis
Glucose
Pyruvate
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
Mitochondrion
ATP
Substrate-level
phosphorylation
ATP
Substrate-level
phosphorylation
ATP
Oxidative
phosphorylation
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
-
Glucose (6-C) is split in the cytosol into two 3-C pyruvate molecules
10 steps
NO oxygen needed
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
Glycolysis
ATP
Citric
acid
cycle
Oxidative
phosphorylation
ATP
ATP
Energy investment phase
Glucose
2 ADP + 2 P
2 ATP
used
4 ATP
formed
Energy payoff phase
4 ADP + 4 P
2 NAD+ + 4 e- + 4 H +
2 NADH + 2 H+
2 Pyruvate + 2 H2O
Glucose
4 ATP formed – 2 ATP used
2 NAD+ + 4 e– + 4 H +
2 Pyruvate + 2 H2O
2 ATP
2 NADH + 2 H+
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made in glycolysis?
-
Substrate-level phosphorylation – ATP produced from the transfer of a
phosphate group from a substrate to ADP
ATP made one at a time
Enzyme
Enzyme
ADP
P
Substrate
+
Product
ATP
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
-
NAD+ - nicotinamide adenine dinucleotide
Coenzyme (form of niacin…a vitamin!)
Accepts 2 e- and a H+
NADH and H+ will be very important later in the respiration reaction, as
they participate in more ATP formation!
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
2 e– + 2 H+
NAD+
Dehydrogenase
O
NH2
H
C
CH2
O
O–
O
O P
O
H
–
O P O HO
O
N+ Nicotinamide
(oxidized form)
H
OH
HO
CH2
NH2
N
N
H
O
H
HO
N
H
OH
N
2 e– + H+
H
Reduction of NAD+
+ 2[H]
(from food) Oxidation of NADH
NADH
H O
C
H
N
H+
NH2
Nicotinamide
(reduced form)
+
H+
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
7.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
How does pyruvate get into the mitochondria for the Krebs
Cycle?
-
Active transport across membrane
3 step process
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
CYTOSOL
MITOCHONDRION
NAD+
NADH
+ H+
O–
S
CoA
C
O
2
C
C
O
O
1
3
CH3
Pyruvate
Transport protein
CH3
Acetyl CoA
CO2
Coenzyme A
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
7.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
How does pyruvate get into the mitochondria for the Krebs
Cycle?
What happens during the Citric Acid Cycle?
8.
-
Mitochondrial matrix
8 steps
“Spins" 2X per glucose (1X for each pyruvate)
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
Pyruvate
(from glycolysis,
2 molecules per glucose)
Glycolysis
Citric
acid
cycle
ATP
ATP
Oxidative
phosphorylation
ATP
CO2
NAD+
CoA
NADH
+ H+ Acetyl CoA
CoA
CoA
Citric
acid
cycle
2 CO2
3 NAD+
FADH2
FAD
3 NADH
+ 3 H+
ADP + P i
ATP
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
7.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
How does pyruvate get into the mitochondria for the Krebs
Cycle?
What happens during the Citric Acid Cycle?
How many ATP so far?
8.
9.
-
4 total, 2 from glycolysis & 2 from Krebs Cycle
ALL from substrate-level phosphorylation
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
7.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
How does pyruvate get into the mitochondria for the Krebs
Cycle?
8. What happens during the Citric Acid Cycle?
9. How many ATP so far?
10. How many electron carriers so far?
- 10 NADH
- 2 FADH2
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
7.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
How does pyruvate get into the mitochondria for the Krebs
Cycle?
8. What happens during the Citric Acid Cycle?
9. How many ATP so far?
10. How many electron carriers so far?
11. What happens during electron transport?
- rxns in inner mitochondrial membrane
- electrons flow from electron carriers to electronegative O2
- many SMALL steps instead of one BIG step
12. Why do electron carriers NEED to “break the fall?”
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
H2 + 1/2 O2
2H
/2 O2
1
+
(from food via NADH)
Explosive
release of
heat and light
energy
ATP
Free energy, G
Free energy, G
2 H+ + 2 e–
Controlled
release of
energy for
synthesis of
ATP
ATP
ATP
2 e–
/2 O2
1
2 H+
H2O
(a) Uncontrolled reaction
H2O
(b) Cellular respiration
Figure 9.13 Free-energy change during electron transport
Glycolysis
Citirc
acid
cycle
ATP
ATP
Oxidative
phosphorylation
ATP
NADH
50
Free energy (G) relative to O2 (kcl/mol)
FADH2
40
FMN
I
Fe•S
O
Cyt b
30
20
Multiprotein
complexes
FAD
Fe•S II
III
Fe•S
Cyt c1
Cyt c
IV
Cyt a
Cyt a3
10
0
2H++
2 O2
1
H2O
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
How does pyruvate get into the mitochondria for the Krebs
Cycle?
What happens during the Citric Acid Cycle?
How many ATP so far?
How many electron carriers so far?
What happens during electron transport?
Why do electrons NEED to “break the fall?”
How is ATP made during chemiosmosis?
Figure 9.14 ATP synthase, a molecular mill
INTERMEMBRANE SPACE
H+
H+
H+
H+
H+
H+
H+
A rotor within the
membrane spins
clockwise when
H+ flows past
it down the H+
gradient.
A stator anchored
in the membrane
holds the knob
stationary.
H+
ADP
+
Pi
MITOCHONDRIAL
MATRIX
ATP
A rod (or “stalk”)
extending into
the knob also
spins, activating
catalytic sites in
the knob.
Three catalytic
sites in the
stationary knob
join inorganic
Phosphate to ADP
to make ATP.
Figure 9.15 Chemiosmosis couples the electron transport
chain to ATP synthesis
Glycolysis
ATP
Citirc
acid
cycle
ATP
Inner
Mitochondrial
membrane
Oxidative
phosphorylation
electron transport
and chemiosmosis
ATP
H+
H+
H+
Intermembrane
space
Protein complex
of electron
carners
Q
I
Inner
mitochondrial
membrane
IV
III
ATP
synthase
II
FADH2
NADH
Mitochondrial
matrix
H+
Cyt c
NAD+
FAD+
2 H+ + 1/2 O2
H2O
ADP +
ATP
Pi
(Carrying electrons
from food)
H+
Chemiosmosis
Electron transport chain
Electron transport and pumping of protons (H+), ATP synthesis powered by the flow
which create an H+ gradient across the membrane Of H+ back across the membrane
Oxidative phosphorylation
1 NADH = 3 ATP (new research indicates 2.5 ATP)
1 FADH2 = 2 ATP (new research indicates 1.5 ATP)
Figure 9.16 ATP yield per molecule of glucose at each stage
of cellular respiration
Electron shuttles
span membrane
CYTOSOL
MITOCHONDRION
2 NADH
or
2 FADH2
2 NADH
2 NADH
Glycolysis
Glucose
2
Pyruvate
2
Acetyl
CoA
+ 2 ATP
by substrate-level
phosphorylation
Maximum per glucose:
6 NADH
Citric
acid
cycle
2 FADH2
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
+ 2 ATP
+ about 32 or 34 ATP
by
oxidative
phosphorylation, depending
by substrate-level
on which shuttle transports electrons
phosphorylation
from NADH in cytosol
About
36 or 38 ATP
Figure 9.16 ATP yield per molecule of glucose at
each stage of cellular respiration (UPDATED)
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
How does pyruvate get into the mitochondria for the Krebs Cycle?
What happens during the Citric Acid Cycle?
How many ATP so far?
How many electron carriers so far?
What happens during electron transport?
Why do electrons NEED to “break the fall?”
How is ATP made during chemiosmosis?
What happens when there is no O2?
- anaerobic respiration (fermentation)
Figure 9.18 Pyruvate as a key juncture in catabolism
Glucose
CYTOSOL
Pyruvate
No O2 present
Fermentation
O2 present
Cellular respiration
MITOCHONDRION
Ethanol
or
lactate
Acetyl CoA
Citric
acid
cycle
Figure 9.17 Fermentation
2 ADP + 2
Glucose
2 ATP
Pi
Glycolysis
O–
C
O
C
O
CH3
2 Pyruvate
2 NADH
+2 H+
2 NAD+
H
2 CO2
H
H C OH
C
CH3
O
CH3
2 Acetaldehyde
2 Ethanol
(a) Alcohol fermentation
2 ADP + 2
Glucose
P i
Glycolysis
2 NAD+
O
C O
H
C
2 ATP
OH
CH3
2 Lactate
(b) Lactic acid fermentation
2 NADH
O–
C
O
C
O
CH3
2 Pyruvate
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
How does pyruvate get into the mitochondria for the Krebs Cycle?
What happens during the Citric Acid Cycle?
How many ATP so far?
How many electron carriers so far?
What happens during electron transport?
Why do electrons NEED to “break the fall?”
How is ATP made during chemiosmosis?
What happens when there is no O2?
How do the other foods we eat get catabolized?
Figure 9.19 The catabolism of various molecules from food
Proteins
Carbohydrates
Amino
acids
Sugars
Glycolysis
Glucose
Glyceraldehyde-3- P
NH3
Pyruvate
Acetyl CoA
Citric
acid
cycle
Oxidative
phosphorylation
Fats
Glycerol
Fatty
acids
Chapter 9: Cellular Respiration: Harvesting Chemical Energy
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Why is respiration important?
What are redox rxns?
What are the 3 main steps of respiration?
What happens during glycolysis?
How is the ATP made?
How do electrons get from glucose to O2?
How does pyruvate get into the mitochondria for the Krebs Cycle?
What happens during the Citric Acid Cycle?
How many ATP so far?
How many electron carriers so far?
What happens during electron transport?
Why do electrons NEED to “break the fall?”
How is ATP made during chemiosmosis?
What happens when there is no O2?
How do the other foods we eat get catabolized?
How is cellular respiration controlled?
Figure 9.20 The control of cellular respiration
Glucose
AMP
Glycolysis
Fructose-6-phosphate
–
Inhibits
Stimulates
+
Phosphofructokinase
–
Fructose-1,6-bisphosphate
Inhibits
Pyruvate
Citrate
ATP
Acetyl CoA
Citric
acid
cycle
Oxidative
phosphorylation