Biochem

A 50 yrs old women is taken to emergency room after being poisoned with arsenic. Arsenic inactivates pyruvate dehydrogenase. As a result of this poisoning. How many ATP equivalents will the oxidation of glucose yield within the muscle under aerobic conditions.?

Which statement is true of glycogen in humans.

Glycogen is a minor form of glucose storage

Glycogen degradation produces glucose 3 phosphate as its Major product.

Glycogen is formed from fatty acids or Glucose.

Linkages between glucose residues are Alpha 1,4 and Alpha 1,6 at branch points

Glycogen stores in muscle are used to directly form GTP

An infant presents to ER with seizures. It was later discovered that her blood sugar was 28mmol/l. Glycogen storage disease (GSD) is suspected and muscle biopsy shows glycogen in which branches contain only a few glucose molecules. Which of the following GSD is most likely ?

Routine examination of urine of an asymptomatic pediatric patient showed a positive reaction with Clinitest ( A copper reduction method of detecting reducing sugars), but a negative reaction with glucose oxidase test. Which one of the following sugar’s is least likely to be present?

A young man presents with symptoms of weakness, fatigue, shortness of breath and dizziness. His Hemoglobin level is < 7gms/dl (normal being 13gms/dl). Red blood cells isolated form patient show abnormally low level of lactate production. Adeficiency of which one of the following is the most likely cause for low hemoglobin.

A 60 years old Alcoholic was brought to the ER . During a night out he had passed out and they were unable to wake him. You as an ER physician have ordered Injection Thiamine and overnight Dextrose. The next morning patient was normal and blood glucose was 75mg/dl and was discharged home. Which of the following enzymes is Thiamine dependent and essential for glucose oxidation in the brain?

A young adult received antibiotics for Urinary tract infection that had a self limiting episode of blood in the urine. Which of the following is most likely?

Phosphate. Which of the following is correct based on the kinetic properties of these two enzymes?

Hexokinase needs lower energy then glucokinase

Hexokinase will reach Vmax at lower glucose concentration than glucokinase

Hexokinase will metabolise more glucose per second.

Glucokinase can metabolise more glucose per second.

Hexokinase has higher Vmax than Glucokinase

A child presents to you. The child appears abnormal and the mother states that the baby was small for gestational age and is developing much differently than her other children. On examination the baby has poor muscle tone, has microcephaly and is hyperventilating. You suspect pyruvate carboxylase deficiency. Which of the following is true?

Child needs further evaluation

The child has an inability to form oxaloacetate from carbohydrates.

Morbidity and mortality can be corrected with early medical intervention.

Clinical sequelae are related to an excessive production of Citrate.

It is an X linked disorder

A young man is training for marathon. He develops severe muscle cramps and weakness while running. You as a doctor have ordered Muscle and liver biopsy. Muscle biopsy show glycogen accumulation and liver biopsy is normal. Which of the following is most likely diagnosis?

A intern is scrubbing into a complicated surgery that is anticipated to last for 8hours and in preparation for it the intern has not eaten or drunk anything for past 6 hours so that he will not have to go to the bathroom in the middle of surgery. After 14hrs of fasting which of the following is most important for maintenance of normal blood glucose levels?

Glycolysis is..............

Hexokinase is important in hepatic glucose metabolism only in the absorptive period.following consumption of a heavy meal.

The regulated reactions are also irreversible reactions.

Fructose2,6- bisphosphate is a potent inhibitor of Phosphofructokinase.

The conversion of glucose to lactate requires the presence of oxygen.

The conversion of Glucose to lactate yields 2 ATP & NADH

Which one of the following reactions is unique to Gluconeogenesis?

Oxaloacetate-------- Phosphoenolpyruvate

Lactate ---------------- Pyruvate

Phosphoenolpyrivate -------------------- Pyruvate

Glucose 6 phosphate ---------------- fructose 6 phosphate

1,3 Bis phosphoglycerate -------------- 3 –Phosphoglycerate

When nitroprusside is given in higher than usual doses it may be accompanied by the administration of Thiosulphate to reduce potential toxic side effects. Which complex of ETC or Oxidative phosphorylation is most sensitive to the toxic byproduct?

Which of the following statements best describes glucose?

It is a ketose and usually exists as a furanose ring in solution.

It is a C-4 epimer of galactose.

It is utilized in biological systems only in the L –Isomeric form.

It is produced from dietary starch by the action of α- Amylase

Homopolysaccharides of glucose, formed by the action of glycosyltransferases are always branched molecules that contain only β- glycosidic linkages.

Biochem

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