Prophyrins Question And Answers

Hemoglobin And Prophyrins

Question 1. Jaundice
Answer:

• The yellow pigmentation of the skin, mucous membrane & deeper tissues due to increased bilirubin levels in the blood is called jaundice
• It occurs when the bilirubin level exceeds 2 mg%

Jaundice Types:

Read And Learn More: BDS Previous Examination Question And Answers

Question 2. Hemoglobin – structure & synthesis.
Answer:

Hemoglobin Structure:

• Hemoglobin is a conjugated protein
• It consists of the protein- globin & iron-containing pigment called heme

1. Globin

• It contains four polypeptide chains, two alpha & two beta chains
• The alpha chain contains 141 amino acids, while the beta chain contains 146 amino acids

2. Heme

• It is a porphyrin derivative known as Protoporphyrin IX with iron at its center

Hemoglobin Synthesis:

• During Kreb’s cycle, the acetic acid is converted into succinyl CoA
• Two molecules of succinyl CoA combine with two molecules of glycine to form pyrrole compound
• Four pyrroles combine to form protoporphyrin
• Protoporphyrin IX is involved in Heme formation along with iron
• Each heme combines with one globin to form hemoglobin

Question 3. Abnormal hemoglobins.
Answer:

Abnormal hemoglobins are the result of mutations in the genes that code for the a and b chains of globin.

As many as 400 mutant hemoglobins are known. About 95% of them are due to alteration in a single amino acid of globin.

Hemoglobinopathies:

It is a term used to describe the disorders caused by the synthesis of the abnormal hemoglobin molecule or the production of insufficient quantities of normal hemoglobin or rarely both.

Sickle-cell anemia (HbS) and hemoglobin C disease (HbC) are the classical examples of abnormal hemoglobins.

Thalassemia, on the other hand, is caused by decreased synthesis of normal hemoglobin.

Question 4. The normal value of bile acids
Answer:

Bile acids:

• In hepatic: 1.93%
• In gall bladder: 9.14%

Question 5. Glycosylated form of hemoglobin
Answer:

• Glucose-derived products of normal adult hemoglobin are referred to as glycosylated hemoglobin
• It is used for monitoring diabetes control
• It is the best index for long-term control of blood glucose levels
• It reflects the mean blood glucose level over a 2-month period prior to its measurement

Value:

• Normal concentration-3-5% of total hemoglobin
• In diabetes- 15% of total hemoglobin

Question 6. Degradation of heme
Answer:

• Heme is split into iron & pigment biliverdin
• Iron goes to the iron pool & is reused
• Biliverdin is reduced to bilirubin by biliverdin reductase
• Bilirubin is released into the blood
• It is taken up by liver cells & gets conjugated
• This conjugated bilirubin is then excreted into the intestine

1. 50% of bilirubin is converted to urobilinogen

• • Most of it enters the liver & re-excreted in bile
  • 5% of it is excreted by the kidney
  • Some of it is excreted in feces as stercobilinogen
  • 50% of bilirubin is absorbed into the blood & enters the liver through the portal vein

Question 7. The fate of bilirubin in the body
Answer:

• Bilirubin is released into the blood
• It is taken up by liver cells & gets conjugated
• This conjugated bilirubin is then excreted into the intestine

1. 50% of bilirubin is converted to urobilinogen

• Most of it enters the liver & re-excreted in bile
• 5% of it is excreted by the kidney
• Some of it is excreted in feces as stercobilinogen

2. 50% of bilirubin is absorbed into blood & enters the liver through the portal vein

Question 8. Bile pigment formation
Answer:

• Bile pigments are biliverdin & bilirubin
• They are formed by heme degradation

Question 9. What are bile salts? How are they tested in the laboratory?
Answer:

• Bile salts are the sodium & potassium salts of bile acids which are conjugated with glycine or taurine

Tests to detect bile salts:

1. Hay’s test

• In this test, the sulfur powder is sprinkled on the surface of urine containing bile salts
• As a result, bile salts sink to the bottom

2. Petternkofer’s test

• Sugar is reacted with concentrated sulphuric acid
• The furfural derivatives condense with bile salts to form a purple ring

Question 10. Define pH. Mention the normal range of blood pH.
Answer:

Definition:

• It is a numeric scale used to specify the acidity or alkalinity of an aqueous solution On this scale
• 7-neutral
• A lower value indicates acidic
• A higher value indicates alkalinity pH stands for the potential of Hydrogen

Normal range of blood pH

• The normal range of blood pH is 7.35 -7.45