Semester spotting

04/11/23 1NAMRATA CHHABRA- BIOCHEMISTRY FOR MEDICS

SPOT QUESTION-1A 28-year-old man complains of a rash on his sun exposed skin, diarrhea and loss of balance. His Urinanalysis results are significant for an increase in neutral amino acid level. The patient is diagnosed with Hartnup’s disease, a defective transport of neutral amino acids in the kidney. Which of the following amino acids would have been found in the urine sample?A. LysineB. TryptophanC. ArginineD. HistidineE. Glutamate


ANSWER- SPOT-1• The correct answer is-Tryptophan, which is the only

neutral amino acid in the given options. Lysine, Arginine and Histidine are positively charged (basic amino acids), whereas Glutamic acid is a negatively charged amino acid (acidic amino acid ).

• Hartnup disease is an absorption defect, transporter deficiency leads to reduced absorption of tryptophan, which is an essential amino acid , as well as a precursor of niacin and neurotransmitters. The patients of Hartnup disease manifest both the symptoms of tryptophan(neurological) as well as niacin deficiencies (pellagra).


SPOT QUESTION-2

A 67-year-old man suffers from congestive heart failure. He is taking Digoxin, which helps the heart to beat more strongly and regularly. Digoxin is an ester that contains a sugar component and a non sugar (aglycone) component attached via oxygen. What is the chemical nature of Digoxin?A. GlycoproteinB. GlycosideC. OligosaccharideD. PolysaccharideE. Disaccharide 04/11/23 4NAMRATA CHHABRA- BIOCHEMISTRY FOR

MEDICS

ANSWER- SPOT QUESTION -2

The correct option is Glycoside. Digoxin is a cardiac glycoside. Glycosides contain a sugar and a non sugar component (aglycone) linked together by O- Glycosidic linkage)


SPOT QUESTION-3

A protein rich nutrient has been checked for the quality of its protein. Hopkin Cole color reaction has come out as negative while all other color reactions for different amino acids are positive? Which amino acid is lacking in the diet? What is your interpretation about the quality of the given protein?


ANSWER- SPOT QUESTION-3

• Hopkin cole reaction is a confirmatory test for Tryptophan.

• Negative Hopkin cole reaction signifies absence of tryptophan in the given protein.

• Since other color reactions are positive, hence the given protein is deficient only in tryptophan (only one essential amino acid is lacking)

• It is thus a class II or incomplete protein.


SPOT QUESTION-4A 54- year-old female who is 68 inches tall and weighs 198 Ib, has reported to the medical emergency complaining of “tight pressure like band of pain’’ across her chest, associated with shortness of breath, sweating, and a sense of light headedness. The symptoms appeared following a heated argument with the neighbor. She has a history of high blood pressure and elevated serum cholesterol. Blood biochemistry has revealed abnormal enzyme profile and high serum total cholesterol, suggestive of Acute Myocardial infarction (Acute M.I.). What is the range of serum total cholesterol in the normal health?Mention any two functions of cholesterol. 04/11/23 8NAMRATA CHHABRA- BIOCHEMISTRY FOR

MEDICS

ANSWER SPOT QUESTION-4

• The serum total cholesterol in normal health ranges between 150-220 mg/dl.

• Cholesterol is a component of biological membranes, myelin sheath and is required for propagation of nerve impulse.

• It is a precursor of vitamin D; bile salts and is also required for the formation of steroids, and sex hormones.


SPOT QUESTION-5

A chronic Alcoholic with impaired liver functions has reported to the medical O.P.D. His serum sample has been sent to the laboratory for total proteins estimation. What do you expect out of the levels of serum total proteins; should they be normal, higher or lower than normal? What is the normal reference range for serum total proteins? Mention any two conditions in which the (Albumin: Globulin) A: G ratio is reversed.


ANSWER SPOT QUESTION-5• Alcoholics are commonly malnourished, and in the

presence of alcoholic liver disease(as in present situation)• The serum total protein level should be lower than normal. • The normal serum total plasma protein ranges between 6-

8 G/dl.• The A: G (Albumin to Globulin) ratio is reversed in

conditions of hypoalbuminemia and hypergammaglobulinemia such as Protein energy malnutrition, liver and renal disorders, chronic diarrhea, chronic infections, leukemias, lymphomas and in HIV infection.


SPOT QUESTION-6

A 23 year old female has been brought to the emergency. She was found semiconscious in her hostel room. Her friends have revealed that she was not taking anything from the last two days after her break up with her boyfriend. She was in good health previously. Physical examination reveals low blood pressure and feeble pulse. Chest and CVS examination are normal. No abnormality has been detected in the abdomen. Blood chemistry reveals low blood glucose levels. What is the significance of low blood glucose, which organ is most affected in this state? What is your opinion about normal reference range of blood glucose?


ANSWER - SPOT QUESTION-6• Glucose is a universal source of energy.• It is a preferred source of energy for

brain and the sole source of energy for cells lacking mitochondria such as red blood cells.

• These are the cells most affected.• Brain is the most affected organ.• In normal health blood glucose ranges

between 60-90 mg/dl.


GLASS WARE

Identify the glass ware (A) and (B)Mention the use of each of them

A B


GLASS WARE

A- is a funnel, It is used to transfer substances into containers that have narrow mouths. Some funnels act as filters, either because of their design of because filter paper or a sieve is placed on the funnel.

B- is a watch glass, they can serve as lids for flasks and beakers. Watch glasses are used for holding small samples for observation under a low-power microscope. They are also used for evaporating liquid off of samples.


GLASS WARE

Identify the glass ware (A) and (B). Mention the use of each of them

A B


GLASS WARE

A- is a glass pipette, Pipettes are droppers calibrated to deliver a specific volume. Some pipettes are marked like graduated cylinders. Other pipettes are filled to a line to reliably deliver one volume again and again.

B- A stirring rod or stir rod is a piece of laboratory equipment used to mix chemicals and liquids for laboratory purposes.


REAGENTS

Which of the two displayed reagents (A and B) is used for the inversion test for sucrose? What is the use of other reagent?

A B


REAGENTS

Reagent B – Concentrated HCl is used for the inversion test, a confirmatory test for sucrose.Reagent A – Concentrated sulphuric acid is used for the Molisch test.


EQUIPMENT

A 34-year-old female has been admitted in the emergency department with Atrial fibrillation. Blood sample has been drawn for estimation of serum electrolytes. Which of the two displayed equipment (A or B)should be used for this estimation?What is the use of second equipment?


EQUIPMENT

• Equipment -A is a colorimeter and equipment B is a photo electric flame photometer.

• Equipment- B is used for measurement of electrolytes

A B


A

EQUIPMENTA 56- year -old chronic smoker has developed worsening cough with purulent sputum and has been admitted to the hospital because of difficulty in breathing. He is drowsy and cyanosedHis arterial blood gas analysis is as follows;p CO2 70 mm HgHCO3

- 26 mmol/LP O2 50 mm Hg The symptoms and blood gas analysis are suggestive of Respiratory acidosis. Blood pH levels remains to be confirmed. Which of the two displayed equipment (A or B)should be used for this estimation?What is the use of the second displayed equipment in the clinical laboratory?


EQUIPMENT

Equipment B- Digital pH meter can be used for the determination of pH.Equipment A is a spectrophotometer, commonly used for the measurement of transmittance or reflectance of solutions.

A B


SPOT QUESTION

The patients of diabetes mellitus are advised to supplement with dietary fiber. How does dietary fiber help these patients? What is the nutritive value of dietary fiber?


ANSWER - SPOT QUESTION

• Dietary fiber promotes utilization of glucose, inhibits absorption of dietary cholesterol and thus regulates blood glucose and serum cholesterol levels, which are high in diabetics.

• It promotes peristalsis, provides roughage , thus relieves constipation, and also protects from piles and colon cancers.

• It has no caloric value since it can not be digested.


SPOT QUESTION

A child develops chronic diarrhea and liver inflammation in the early infancy when the mother begins using formula that includes the corn syrup. Evaluation of the child demonstrates sensitivity to fructose in the diet. Most of the unutilized dietary fructose is either converted to glucose or is reduced to sugar alcohols in the body.Name the sugar alcohol/s obtained from reduction of fructose.Which dietary substance containing fructose should be avoided when feeding or treating this child? 04/11/23 26NAMRATA CHHABRA- BIOCHEMISTRY FOR

MEDICS

ANSWER- SPOT QUESTION• Fructose upon reduction

produces sorbitol and mannitol since a new asymmetric carbon atom is generated upon reduction at C-2. Sorbitol and mannitol are C-2 epimers.

• Fructose rich food items that can be avoided are Table sugar, honey, fruit, juices and corn syrup etc.


CASE STUDYA 16-year-old man hospitalized in a state of coma after an automobile accident, was started on intravenous hyper alimentation. Although a complete vitamin mixture was present in the solution, fat was omitted in the diet because of solubility problem.After 3 months, the patient developed skin lesions, hair loss and a fatty liver.Plasma lipid analysis revealed normal cholesterol level but a very low level of Arachidonic acid.24- Hour urine analysis indicated a low excretion of prostaglandin metabolites. What is the biochemical basis of clinical manifestations?What is the basis of low excretion of prostaglandin metabolites?


DISCUSSION- CASE STUDY• The patient has exhibited signs

of essential fatty acid deficiency since the fats are omitted in the diet.

• Low prostaglandins are due to low Arachidonic acid.

• Arachidonic acid is a precursor of Eicosanoids, since plasma arachidonic acid is low, there is les synthesis and hence there is less excretion of prostaglandins in the urine.


SPOT IDENTIFICATION

Identify the structure; mention the names of the biomolecules having this structure. 04/11/23 30NAMRATA CHHABRA- BIOCHEMISTRY FOR

MEDICS

ANSWER- SPOT IDENTIFICATION

• It is beta pleated sheet structure, a secondary structure of proteins.

• Beta keratin, silk fibroin, carbonic anhydrase and flavodoxin predominantly contain beta pleated sheet structure.


SPOT IDENTIFICATION

The individual reaction catalyzed by Enzyme E1 and E2 is shown below-

1) Comment on the class of enzyme and 2) Give examples of each of the class of enzymes (E1 and E2)

E1

E2


SPOT IDENTIFICATION

• E1- is a Hydrolase- All proteolytic enzymes are hydrolases

• E2 is a Transferase Example- Transaminase, Methyl transferase

04/11/23 NAMRATA CHHABRA- BIOCHEMISTRY FOR MEDICS 33

Identify and draw the crystals

State the clinical situation if the above said substance is excessively excreted in urine ?


OSAZONE CRYSTALS• These are lactosazone crystals

(powder puff).• Lactosuria is the term used to

denote excessive excretion of lactose in urine and that occurs in conditions of Lactose Intolerance.

• The undigested lactose is absorbed by pinocytosis that goes to systemic circulation to get excreted through urine.


CASE STUDY

A 54- year-old woman who was bed bound in a nursing home began to develop swelling of her left leg. She was evaluated with venous Doppler ultra sound and was found to have a deep vein thrombosis. She was immediately started on heparin to prevent the clot from further enlarging What is the chemical nature of heparin ? What is the mechanism of action of heparin ?


DEEP VEIN THROMBOSIS

04/11/23 NAMRATA CHHABRA- BIOCHEMISTRY FOR MEDICS 37

CASE STUDY- DISCUSSION

• Heparin is a sulfated mucopolysaccharide• It is an anticoagulant widely used in clinical

practice.• Binding of Heparin to antithrombin produces

conformational changes which promote the binding of the latter to “thrombin” which is inhibited, thus fibrinogen is not converted to fibrin and the coagulation is inhibited.


PLASMA PROTEIN ELECTROPHORESIS

Identify peak E and mention two important functions of the biomolecule that occupies this region


PLASMA PROTEIN ELECTROPHORESIS

• The “E” peak is of gamma globulins• The gamma globulins are increased in various

acute and chronic infections, liver diseases, multiple myeloma , HIV infection and various cancers.

• “A” peak is of Albumin• ‘B” alpha-1• “C” of Alpha-2• “D” is of Beta globulins.04/11/23 40NAMRATA CHHABRA- BIOCHEMISTRY FOR

MEDICS

CASE STUDY

A 48- year-old man presented with short history of severe low backache, loss of weight and diminished appetite. X-ray skull showed punched out lesions. Serum electrophoresis revealed an abnormal band between β globulins and γ globulin region.What is the probable diagnosis ?Which specific protein is detected in urine of such patients ?


CASE DISCUSSION

• It is a case of multiple myeloma, a cancer of plasma cells. The symptoms and electrophoretic pattern are typical of multiple myeloma.

• Bence jone’s proteins are excreted in a patient suffering from multiple myeloma.04/11/23 NAMRATA CHHABRA- BIOCHEMISTRY FOR

MEDICS42

FURTHER READING

• Follow the link- Biochemistry for medics- Lecture notes by -Professor(Dr.) Namrata Chhabra

http://www.namrata.co/


Education

Semester spotting