Special: Hunters who chased the rabbits for extended
time and killed them for food, complained that the meet was
sour. Why?
1. In 1905 scientists observed that fermentation by yeast
extract required inorganic phosphate as essential
component in the extract. Why?
Which reaction of glycolysis requires inorganic
phosphate?
2. How many molecules of the following metabolites
are produced during the given pathways from one
molecule of Glucose?
a) Pyruvate during glycolysis
b) Lactate during anaerobic Glycolysoshomolactic fermentation
c) Ethanol during glycolysis -Alcohalic
fermentation
d) CO2 during glycolysis-Alcohalic
fermentation
e) CO2 and Acetyl Co-Enzyme A during
Glycolysis followed by PDC reaction
f) ATP during in each of the four pathways in a,
b, and c and e.
g) NADH during all the four pathways
3. In a fermenter with one liter liquid capacity 342 grams
of sugar is catabolized using active yeast under
anaerobic condition. Answer the following;
a. What will the percentage of alcohol (V/V) in the
brew when all the sugar is fermented?
b. How many grams of Disodium arthophosphate will
be consumed (Na2HPO4)?
c. How many grams of ATP and CO2 will be
produced?
Mol. Wt: Sugar
=342
ATP
=509
Na2HPO4 =142
EtOH
=46
CO2
=44
Specific density of alcohol =0.789
4. Name all the kinases involved in glycolysis
5. Name the substrates in forward direction of each
kinase reaction.
6. Name the reaction involving oxidation-reduction
reaction in glycolysis.
7. Which compound is reduced in the reaction in q.6
8. a. Which component is an electron acceptor
(oxidizing agent) in Glycolysis?
9. How many reactions of glycolysis involve phosphoryl
group transfer? Provide the names of enzymes.
10. Which reaction in glycolysis is responsible for the
net gain of ATP during this pathway?
11. Name the reactions in glycolysis involving
phosphate group transfer without any involvement of
ATP or ADP.
12. During homolactic fermentation in muscle, there is
production of Lactic acid, which lowers the pH
causing fatigue. There is no ATP production during
this step of the reaction. Why should this reaction be
there?
13. What is the target for the first nucleophilic attack in
the GAPDH reaction?
14. Despite the low amount of ATP generated during
glycolysis. Why this is the preferred pathway in
muscle during fast movement?
15. What can you guess about the mechanism of the
reaction on the overhead, with help of the
observations made during the experiments?
a. Treatment of the enzyme with a protein
phosphatase results in the inactivation of this
enzyme.
b. If the phosphate group of the substrate is
labeled with radioactive 32P, a fraction of the
enzyme also gets labeled with the 32P.
c. This reaction does not require ATP hydrolysis.
16. Why is glucose phosphorylated in the first step of
glycolysis?
17. The standard free energy change of the GAPDH
(reaction #6) is positive. How does this reaction
proceed in forward direction?
18. Which is the most important regulatory enzyme for
the flux of glycolysis?
19. The substrate cycle is also called futile cycle, Why?
20. Is futile cycle really a futile exercise? If not what is
the importance of this cycle.
21. Which is the most correct statement from the
followings;
Pyruvate acts as an oxidizing agent in
i. Pyruvate kinase reaction.
ii. In lactate dehydrogenase reaction of
homolactic fermentation.
iii. In both the lactate DH and alcohol
dehydrogenase reaction during homolactic
and alcoholic fermentation.
iv. In glycolysis.
22. Yeast carry out alcoholic fermentation pathway to
i. Generate CO2 for the beer.
ii. Generate alcohol to relax and get drunk.
iii. Produce ATP under aerobic condition.
v. Regenerate NAD+ for glycolysis reactions
producing ATP under anaerobic condition.
23. Deficiency of thiamine or arsenate poisoning lead to the
similar symptoms and mostly brain functions are affected in
these diseases. Why?
24. What enzymes are affected by thiamine deficiency?
25. Insulin generally promotes anabolic pathway i.e. synthesis
of glycogen then why should it activate PDC?
26. a. What side reaction would take place if E1 was separated
from PDC?
c. Which of the dehydrogenases have FAD cofactor?
27. Case Study: A child is admitted to the hospital with
neurological differences, partial paralysis and poor muscle
strength. Initial tests indicated no infection, no arsenate in the
blood, and no family history of any metabolic disorder. There
were high levels of pyruvate and alfa keto gluterate in the
system. As an expert in metabolism, what will be your opinion
about the diagnosis of this patient?
28. Name all the cofactors involved with PDC reaction and
indicate their association with different enzymes of the PDC
complex.
29. What is the role of E3 in PDC reaction?
30. What is pasture’s effect?
NEWS
Nature Medicine 10, 7 (2004)
doi:10.1038/nm0104-7b
Fatal flaw in baby formula sparks reform in Israeli
ministry
Luba Vikhanski
Tel Aviv
A German baby formula that caused severe vitamin deficiency in 15
Israeli infants and killed 2 has led to a radical revamp of Israel's
regulatory framework for infant formula, making the requirements
more stringent than for pharmaceuticals.
Recipe for disaster: A series of errors led to rare cases of beriberi, a
deficiency of thiamine.
Reuters/Nir Elias NIR/RKR/CRB
In early November, several Israeli babies were hospitalized with the
neurologic and cardiac symptoms of beriberi, a severe deficiency in
thiamine, or vitamin B1. Thiamine has essential roles in converting
carbohydrates to energy and in the synthesis of the neurotransmitter
acetylcholine.
The infants had all been fed Remedia Super Soya 1, a kosher infant
formula manufactured exclusively for Israel by the German company
Humana. The affair prompted a police investigation in both Israel and
Germany. Subsequent testing revealed that, contrary to product
labels, the formula almost entirely lacked thiamine. The product has
since been withdrawn from the market.
Humana, the oldest and one of the largest baby food companies in
Germany, admitted to a series of blunders and fired four workers.
According to a company spokesman, a Humana employee failed to
add thiamine to the product because the vitamin naturally occurs in
soybeans. The soy was treated with heat, however, which destroyed
the thiamine.
Because follow-up quality testing didn't pick up on the deficiency, the
scandal raised questions about the adequacy of the Israeli Health
Ministry's supervision. In response, the Ministry changed its
regulations for baby formulas. Previously, manufacturers had to
submit laboratory test results for a formula's ingredients, after which
the Ministry performed random testing of selected ingredients. Under
the new regulations, the Ministry will test all batches of locally
produced or imported formulas.
In effect, the Ministry will be duplicating the quality assurance
process of the manufacturer—a practice unheard of anywhere else in
the world, says Dorit Nitzan-Kaluski, director of the Ministry's Food
and Nutrition Administration. "It's a catastrophe for the country
because it's a huge expense and a huge mess, but there's no choice,"
says Nitzan-Kaluski. "We've lost our credibility."
In the US, manufacturers submit lab tests for each new infant
formula to the Food and Drug Administration, but the agency doesn't
retest the formulas before they go to market. It does, however,
perform annual inspections of manufacturing plants and collect
samples for nutrient analyses.
Beriberi is rare in the US and in Europe because most foods there are
vitamin-enriched, and is seen primarily in chronic alcoholics or in
people on dialysis. It is more common in parts of East Asia, where
milled or polished rice is a dietary staple, but its incidence there has
also dropped sharply as economic conditions have improved.