Sindh MDCAT 2026 Past Paper

1- The structure of Tobacco Mosaic Virus (TMV) is:

A. Helical
B. Tadpole
C. Polyhedral
D. Circular

Answer : A. Helical

2- The genetic material of the causative agent of AIDS is:

A. Single-stranded RNA
B. Double-stranded RNA
C. Single-stranded DNA
D. Double-stranded DNA

Answer : A. Single-stranded RNA

3- Glycerol, a component of fats, enters cellular respiration at the level of:

A. Glycolysis
B. Krebs cycle
C. Electron transport chain
D. Glycogenolysis

Answer : A. Glycolysis

4- During hot temperatures, we feel cool mainly because water has:

A. Low heat capacity
B. High heat of vaporization
C. Polarity
D. Ionization property

Answer : B. High heat of vaporization

5- An organic compound that is insoluble in water but soluble in organic solvents such as acetone is:

A. Lipid
B. Nucleic acid
C. Protein
D. Carbohydrate

Answer : A. Lipid

6- The primary role of proteins in living organisms is to:

A. Act only as digestive enzymes
B. Perform structural and functional roles
C. Store genetic information
D. Provide the main source of genetic material

Answer : B. Perform structural and functional roles

7- Which of the following nitrogenous bases is present in DNA?

A. Adenine, Cytosine, Uracil and Thymine
B. Guanine, Cytosine, Uracil and Thymine
C. Adenine, Guanine, Cytosine and Uracil
D. Adenine, Guanine, Cytosine and Thymine

Answer : D. Adenine, Guanine, Cytosine and Thymine

8- A decrease in enzyme activity with a decrease in pH is mainly due to:

A. Increase in enzyme concentration
B. Increase in substrate concentration
C. Alteration of the active site
D. Ionization of amino acid side chains

Answer : C. Alteration of the active site

9- With an increase in temperature, enzyme activity initially increases because of an increase in:

A. Concentration of enzyme and substrate
B. pH of the solution
C. Motion of only substrate molecules
D. Motion of enzyme and substrate molecules

Answer : D. Motion of enzyme and substrate molecules

10- A non-competitive inhibitor generally acts by:

A. Binding to the active site
B. Binding to a site other than the active site and altering enzyme structure
C. Increasing enzyme concentration
D. Binding directly to the substrate

Answer : B. Binding to a site other than the active site and altering enzyme structure

11- Which structure is characteristic of animal cells and generally absent in higher plant cells?

A. Microtubules
B. Cell membrane
C. Centrosome
D. Mitochondria

Answer : C. Centrosome

12- Which structure appears cylindrical under an electron microscope?

A. Centriole
B. Mitochondrion
C. Endoplasmic reticulum
D. Golgi apparatus

Answer : A. Centriole

13- Identify the correctly matched structure and function:

A. Chloroplast — Aerobic respiration
B. Mitochondria — Digestion
C. Ribosome — Photosynthesis
D. Golgi body — Packaging of materials

Answer : D. Golgi body — Packaging of materials

14- Which of the following represents the correct pathway for secretion of a protein from a cell?

A. Nucleus -> Ribosome on rough ER -> Golgi apparatus -> Secretory vesicle
B. Nucleus -> Golgi apparatus -> Ribosome -> Secretory vesicle
C. Golgi apparatus -> Nucleus -> Rough ER -> Secretory vesicle
D. Ribosome -> Nucleus -> Golgi apparatus -> Lysosome

Answer : A. Nucleus -> Ribosome on rough ER -> Golgi apparatus -> Secretory vesicle

15- The movement of food through the gastrointestinal tract is mainly due to:

A. Osmosis
B. Diffusion
C. Gravity
D. Peristalsis

Answer : D. Peristalsis

16- Deoxygenated blood from the liver is carried to the:

A. Vena cava
B. Aorta
C. Kidney
D. Intestine

Answer : A. Vena cava

17- The primary role of semilunar valves in the heart is to:

A. Increase blood pressure in arteries
B. Separate the right and left ventricles
C. Prevent backflow of blood into the ventricles 
D. Prevent backflow of blood into the atria

Answer : C. Prevent backflow of blood into the ventricles

18- The second heart sound ("dub") is produced mainly due to the:

A. Closure of atrioventricular valves
B. Opening of atrioventricular valves
C. Closure of semilunar valves
D. Opening of semilunar valves

Answer : C. Closure of semilunar valves

19- The major cardiac muscle tissue of the heart is present in the:

A. Endocardium
B. Myocardium
C. Pericardium
D. Epicardium

Answer : B. Myocardium

20- The layer of the heart that contains cardiac muscle and conducting fibres is the:

A. Epicardium
B. Pericardium
C. Myocardium
D. Endocardium

Answer : C. Myocardium

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