Biochemistry mcqs for first year mbbs

Biochemistry MCQs for first year mbbs:

1. Signaling in which a molecule is produced by one cell and acts on a neighboring target cell is known as A. Endocrine signaling
2. Direct cell to cell signaling
3. Paracrine signaling
4. Autocrine signaling
5. Transduction

 

 

2. Steroids are derived from

-Cholesterol

-Phospholipid

-Carbohydrate

-Fatty acids

-Triglycerides..

 

3. Michaelis constant Km is:-

-Numerically equal to ½ Vmx

-Dependent on enzyme Conc.

-Independent of pH

-Numerically equal to substrate conc. That gives half the value of maximal velocity

-Increased in the presence of non-competitive inhibitor

 

4. AST and ALT belong to which class?

-Transaminase

 

5. A sulphydryl (SH) bond is present in which compound?

-Cystein

-Tryptophan

-Histidine

-Alanine

-proline

-methionine

 

6. The rate-limiting step in heme synthesis is formation of 1.Gamma ALA 2.Porphobilinogen 3.Uorporphyrinogen 4.Coproporphyrinogen

 

7. The enzyme responsible for conjugation of Bilirubin.

-A. Bilirubin oxidase,

-B. Bilirubin carboxylase,

-C. Bilirubin conjugase,

-D. Bilirubin glucosyl transferase,

-E. Bilirubin phosphorylase

 

8 The first porphyrin ring synthesized during heme synthesis.

-Coproporphyrinogen

-Uroporphyrinogen

-Porphobilinogen

-Porphyrinogen

-Protoporphyrinogen

-None of above

 

 

9. Which one is non-reducing disaccharide ??

-Maltose

-Trehalose

-Galactose

-None of these

 

10. Metabolic alkalosis linked with vomiting or gastric aspiration is due to loss of

Hydrogen

– Chlorine.

– Sodium.

– Potassium.

– Bicarbonate.

– None

MCQs From 11 – 20:

11. Steroid hormone are synthesized

a. Cholesterol

b. Phospholipid

c. both

d. none

 

12. The child in prolong vomiting n gastric aspiration! Back before he on bottle feed since birth! Which immunoglobin is in excessive

-Igi

-Ig

-Igm

-None

 

13. Which of the following is involved in the formation of proline and hydroxy proline in synthesis of collagen A.Pridoxy phosphate

B.biotin

C.vitamin A

D.ascorbic acid

E.cytocine

 

14.Which of the following statement about vitamin D is correct:

-In chronic renal failure, oral administration of 1,25-dihydroxy cholecalciferol is given.

-Vitamin D is required in the iet for the people exposed to sunlight.

-25-hydroxycholecalciferol is the active form of vitamin D.
-Vitamin D decreases serum calcium level.

-None of the above is correct.

 

15. Which of the following is correct…. 1.Chymotripsin acts in stomach on peptide bonds 2.Trypsin is an exo peptidase that liberates free amino acids 3.Pepsinogen is activated by entero peptidase 4.Pepsin is an endo peptidase secreted by pancreas 5.Trypsin act as activator for all zymogen of pancreatic proteases

 

16. surfactant for lungs 1.dipalmitoil lecithin 2.niacin 3.pentothenic acid 4.nicotinic acid 6.none

 

17. A patient presented with severe anterior abdominal pain radiating through his back. Laboratory examination revealed elevated serum amylase. What is the condition patient is suffering from? A) MI B) acute pancreatitis C) stroke D) acute hepatitis

 

18. How are nucleotides linked?
    – >3′-5′ Phosphodiester linkage

– Peptide bond

-Glycosidic linkage

-Hydrophobic linkage

 

19. which one these is a homopolysachride 1.Dextrin 2.Hyaluronic acid 3.Cellulose 4.Heparin 5.Cheratin

 

20. Hypokalcimea about concentration <35 nmol is due to A.renal loss B. GI loss C.Diuretics D.Insulin administration E.All of above

MCQs From 21 – 30:

21. Mucopolysacharides are also called

-glycoproteins

-homopolysachrides

-glycosaminoglycans

-heteropolysachrides

-glycogen

-mucoprotiens

-glycoprotiens

 

22. Which of the following cannot cross cell membrane to interact with intracellular receptors: A. Insulin B. Vitamin D

 

 

25. Which of the statements about lipids/fatty acids is incorrect

-Most unsaturated fatty acids exist in trans form

-The more unsaturated the fat is the more the melting point decreases

-Membrane lipids mostly contain unsaturated F.A.

-Lipids in tissue that are subjected to cooling are more unsaturated.

-Naturally occuring unsaturated long chain F.A are nearly all of trans configuration.

-Linoleic acid is an essential F.A.

 

26. Nitrogenous base absent in DNA but not present in RNA

-Uracil

-Adenine

-Guanine

-Cytosine

-Thymine

 

 

27.Niemman Pick’s disease is due to reduced action of

-Sphingomyelinase

 

28.Vit. A deficiency causes

-Night Blindness

 

29. Denaturation of Protein involves breakage of which two bonds

-Hydrogen and Hydrophobic

 

30. Respiratory chain reaction occurs in.. a. Cell membrane b. Mitochondria

 

MCQs From 31 – 35:

31. Phosholipid present in the lungs is:A ) CardiolipinB) PlasmalogenC) CephalinD) Dipalmitoyl lecithin

 

32. Antibody which can cross the placenta to fetus is (A) IgG (B) IgM (C) IgE (D) IgA

 

33. Respiratory chain is present in

-Mitochondria

-Endoplasmic reticulum

-Ribosome

-Golgi apparatus

 

34. A person having allergic infection will have

– IgE

– IgG

– IgA

– IgD

 

35. Which of the following antibody id the largest?

– IgG

– IgE

– IgM

– IgA