Download Electron Transport Chain

CELL RESPIRATION
&
METABOLISM 2
Dr. Perkins
OVERALL EQUATION
Aerobic Cellular respiration
ATP forms in the Mitochondrion
Know the
parts of the
mitochondrion.
Click here for
a video
How does ATP form in the mitochondrion?
STEP 1:
Formation
of Acetyl
CoA.
After
one
Click HERE
6-carbon glucose molecule breaks
down into two 3-carbon pyruvate molecules,
pyruvate enters the mitochondrion.
A single carbon is removed and breathed out
of the body as carbon dioxide.
When carbon dioxide is formed,
The other two carbons attach
a molecule
energyto
is released
in the form of
electrons
thatCoenzyme
are captured by
called Coenzyme A, forming
Acetyl
NAD to form NADH + H+.
A (Acetyl CoA)
Yield 1: NADH per pyruvate.
The Krebs Cycle
PRODUCTS:
3 NADH
1 FADH2
1 ATP (per Pyruvate)
WASTE PRODUCTS:
2 carbon dioxide
For an
explanation,
Click HERE
Electron Transport Chain
1. NADH or FADH2 bring electrons to the membrane
Electron Transport Chain
2. In a series of redox reactions, electrons are
transferred from one complex to the next.
Electron Transport Chain
3. Some of the energy drives proton pumps.
Electron Transport Chain: Chemiosmosis
4. Protons accumulate in the intermembrane
space, and they diffuse through ATP synthase
driving the synthesis of ATP.
Electron Transport Chain: Chemiosmosis
5. Oxygen attracts the electrons at the end
of the chain and is converted to water.
ATP BALANCE SHEET
2
glucose
ATP
4
Glycolysis
e- + H +
2 NADH
 2 FADH2
CYTOPLASM
2 pyruvate
ATP
(2 ATP net)
e- + H +
2 CO2
2 NADH Overview of Aerobic
- + H+
eRespiration
6 NADH
e- + H +
Krebs
2 FADH2
Cycle
e-
See page
116
of text
4 CO2
Electron
Transfer
Phosphorylation
H+
2
30
ATP
ATP
water
e- + oxygen
Typical Energy Yield: 36 ATP
OF ENERGY
NADH  2.5 ATP REVIEW
AND FADH
1.5 ATPYIELD
from ETC
Interconversion of Glucose and Glycogen
Glycogenesis
Glycogen synthase
Glycogenolysis
Glycogen phosphorylase
Glucose-6-phosphatase
Glucose from glycogen is
in the form of glucose
1-phosphate, so cannot
leave muscle or
heart cells.
Glucose is Converted to Glycogen or FAT
When more food
energy is taken into
the body than is
needed to meet
energy demands,
glucose is converted
into glycogen and fat,
and ATP production is
inhibited
Acetyl CoA is a branchpoint
}
Lipogenesis
Why is fat our long term energy storage molecule?
1 g of fat = 9 kcal of energy
1 g of CH2O or protein = 4 kcal of energy
WHITE FAT (White adipose
tissue) - where most of our
triglyceride are stored.
Adipocytes
LIPASE carries out lipolysis, the
breakdown of triglycerides
into fatty acids and glycerol.
Lipolysis can happen in adipocytes; free
glycerol goes to the liver, where it is used
to make glucose, which is sent to the blood
β-oxidation
Fatty acid
breakdown for
great ATP
production.
How much? –
depends on length
of the chain
NOTE THE CONVERSIONS
TO ATP ON PAGE 120
OF TEXTBOOK.
CLICK HERE FOR A YOU TUBE
EXPLANATION OF TALLYING ATPS
BROWN ADIPOSE TISSUE
- Involved in thermogenesis (heat production), esp. in newborns, but some in
adults
- Sympathetic release  norepinephrine  brown fat forms UCPI H+ leaks
out of inner mito. membrane, less ATP is formed  stimulates beta-oxidation
for more heat generation
UCP-1: an uncoupling protein
KETONE BODIES
Can provide
energy!
a. When the rate of lipolysis exceeds
the rate of fatty acid utilization (as in
Acetone has
dieting, starvation, or diabetes), the
a fruity odor
in breath
concentration of fatty acids in the
blood increases.
b. Liver cells convert the fatty acids into
acetyl CoA and then into ketone
bodies.
c. These are water-soluble molecules
that circulate in the blood.
d. Build-up in the blood can cause
Can be dangerous at high leve
ketosis
To read more about it,
Click HERE
causing ketoacidosis and
ketonuria
PROTEIN
• provides nitrogen;
replace other proteins
• Excess amino acids:
– used for energy
– converted into
carbohydrates or fat.
• Bodies make 12 of the
20 amino acids. 8 of
them (9 in children)
come from the diet
(essential).
Nitrogen Balance
• NORMAL
• POSITIVE
– Take in more than
excreted
• NEGATIVE
– Excrete more than
is taken in
Transamination
Oxidative Deamination
- Amino acids give their NH3 to
α-ketoglutarate, and glutamic acid
is formed
- Glutamic acid gives its NH3 to
CO2
- Remaining keto acids can form
glucose (gluconeogenesis)
Interconversion of
Glycogen, Fat, and
Protein
Glucose and
ketone bodies
come from the
liver
Lactic acid and amino
acids come from muscle
Fatty acids come
from adipose tissue
c
Additional Resources
• ATP & Respiration: Crash Course, click HERE
• Easy explanation of cellular respiration, click
HERE