Download All 3 fates of pyruvate from glycolysis provide for the regeneration of

Review: can you…
Explain how Carbs are digested & absorbed
Draw the steps involved in Glycolysis
Compare and contrast aerobic respiration
to two different types of fermentation
Discuss the 3 possible fates of Pyruvate
Energy
yield from
complete
oxidation of
glucose
(e- loss)
via aerobic
respiration
anaerobic
fermentation
results in
just 2 ATP
30 to 34
Yield of ATP from the Complete Oxidation of One
Glucose Molecule in a Skeletal Muscle Cell.
How is all of that ATP used?
Cell constituent
Number of
molecules per
cell
Molecules
synthesized per
second
Molecules of ATP
required per second
for synthesis
DNA
1
0.00083
60,000
RNA
15,000
12.5
75,000
Polysaccharides
39,000
32.5
65,000
Lipids
15,000,000
12,500.0
87,000
Proteins
1,700,000
1,400.0
2,120,000
Just focusing on building molecules (synthesis);
gives you a taste of ATP driven reactions.
Glucose is stored in muscles and liver :
Glycogen = animal starch (glucose storage molecule).
Muscle: glucose source for glycolysis
Liver: glucose source for maintenance of
blood glucose levels
Comparing glycogenesis to glycogenolysis
Separate pathway energy needs.
Separate control of each pathway.
What does your body do if you don’t
have enough glucose?
Gluconeogenesis:
Needed to produce glucose for the brain
when food isn’t available.
Glycogen stores are depleted
in 12 to 18 hours.
Use other non-carbohydrate sources
(glycerol,lactate, some amino acids, & (in plants) acetyl-CoA)
to make glucose for brain fuel.
The liver is the major site of
gluconeogenesis.
The “opposite” (sort of) processes of
gluconeogenesis (pyruvate to glucose)
& glycolysis (glucose to pyruvate)
are not exact opposites.
Additional step due to energy needs
The relationships among 4 common metabolic
pathways that involve glucose.
Gerti and Carl Cori won
1947 Nobel Prize in
physiology / medicine for
discovery of the enzyme
that starts the conversion
of glycogen to glucose.
The Cori cycle is
named after them.
The Cori cycle: processing lactate
made during anaerobic exercise
The Pentose Phosphate Pathway (PPP)
DNA & RNA need 5-C sugar ribose,
formed in pentose phosphate pathway (PPP). PPP is a
network of reactions
(Glycolysis is largely a straight-thru pathway).
We can make different products depending upon body’s
needs.
PPP generates various sugars (e.g. ribose), & also
produces NADPH, required by cells for biosynthesis
rxns.
Hormonal Control of
Carbohydrate Metabolism
• Enzymes control the metabolism of
carbohydrates, but...
• Several hormones also affect Carb.
metabolism
– Insulin
– Glucagon
– Epinephrine
Insulin reduces glucose in the blood and
stimulates conversion of glucose to fats, proteins,
ribulose 5-phosphate and glycogen;
inhibits the conversion of fats, proteins, glycogen
and ribulose 5-phosphate to glucose
Types of diabetes mellitus
Type 1: autoimmune disorder against the lslet cells
of pancreas: deficiency in insulin. Usually diagnosed
between 5-20. Insulin shots necessary.
Hypoglycemia (too little glucose) may
result.
Type 2: 80-90 % of all diabetics in US: usually
diagnosed over age 40. relative insulin deficiency:
either decreased production of insulin, or cells
become insulin resistant.
Strong genetic component: very high in Native
Americans; high in Blacks & Hispanics. Obesity
major risk factor (often controlled with weight loss).
Epinephrine a.k.a. adrenalin
Glucagon is a 29 amino acid
peptide hormone formed and
released from the  cells of
the islets of Langerhans, in
the pancreas.
Glucagon is a hormone that
opposes the action of insulin
- mainly in the liver.
Epinephrine & glucagon have opposite effects to insulin.
Act to increase glucose in the blood.
Stimulate conversion of fats, glycogen and pyruvate
to glucose
Inhibit conversion of glucose to fats, glycogen and pyruvate
The series of events by which the hormone
epinephrine stimulates glucose production.
Stimulates
adenyl cyclase
to make cAMP
cAMP released to
interior activates…
Quick energy molecule
glucose 6-phosphate forms
Glycogen phosphorylase,
which starts glycogenolysis