Aptitude MCQ Quiz Hub

1. Enzymes _________ the activation energy of a chemical reaction
Increases
Decreases
Does not effect
Increases or decreases depending upon individual enzyme

2. A three dimensional dcavity bearing a specific charge by which the enzyme reacts with its substrate is called
Active site
Binding site
Catalytic site
Allosteric site

3. Which step causes activation of catalytic site of an enzyme?
Change in pH of the surroundings.
Formation of Enzyme Susstrate complex.
Change in the charge of the active site.
Change in temperature

4. Lock and Key model was proposed by
Emil Fischer
Koshland
Robin Williams
Rudolph Virchow

5. Which statement is incorrect about Lock and Key Model?
Specific enzyme can transform only a specific substrate
Active site of an enzyme is a non flexible structure.
Active site does not change before during or even after the reaction.
It explains the mechanism of every chemical reaction.

6. The rate of reaction is directly proportional to the concentration of an enzyme which statement is incorrect in this respect:
Increase in enzyme molecule increases the available active sites.
This relation is for unlimited time period with unlimited enzyme concentration
If the concentration is doubled the rate will become two fold.
None of these.

7. If the concentration of enzyme is kept constant and amount of substrate is increased a point is reached where increase in substrates concentration does not affect the reaction rate because of
Enzymes get denatured at higher substrate conc.
Rate of reaction is indirectly proportional to substrate concentration at this point.
All the active sites on enzyme molecule are occupied.
None of these.

8. If more substrate to already occurring enzymatic reaction is added more enzyme activity is seen because:
There is probably more substrate present than there is enzyme.
There is probably more enzayme available than there is substrate.
There is probably more product present than there is either substrate or enzyme.
The enzyme substrate complex is probably failing to form during the reaction.

9. If more substrate to already occurring enzymatic reaction is added and there is no effect on the rate of the reaction what is the form given to this situation:
Saturation
Denaturation
Composition
Inhibition

10. The active site of an enzyme:
Never changes
Forms no chemical bond with substrate
Determined by structure and the specificity of the enzyme.
They are non specific in their action.

11. Excessive increase in temperature of medium causes the enzyme molecule to
Activate
Unaffected
Denatured
None of these.

12. Extreme change in pH results in:
Change in ionization of amino acids at the active site of the enzyme.
Change in the ionization of the substrate.
Denaturation of the enzyme
Increase in the reaction rate

13. Optimal temperature of enzymes present in human body is
27?C
37?C
47?C
30?C

14. A chemical substance which can react (in place of substrate) with the enzyme but is not transformed into product/s and thus blocks the active site temporarily or permanently is called
Co-enzyme
Blocker
Inhibitor
Cofactor

15. Inhibitors which block the enzyme by forming weak bond are called
Competitive inhibitors.
Non-competitive inhibitors
Irreversible inhibitors.
Both a and b

16. A substance which binds at the active site of the enzyme but does not result in the formation of the products is called:
Irreversible inhibitor
Reversible inhibitor
Competitive inhibitor
Non-competitive inhibitor

17. The structure of an enzyme is altered by:
Irreversible inhibitor
Reversible inhibitor
Competitive inhibitor
Non-competitive inhibitor

18. Malonic acid is an example of:
Irreversible inhibitor
Reversible inhibitor
Competitive inhibitor
Non-competitive inhibitor

19. If enzyme concentration is low than substrate pH and temperature values are equal to requirement then which of the following will increase rate of reaction.
increase in concentration of enzyme
increase in concentration of substrate
increase in pH
increase in temperature

20. The word Archaeobacteria (a division of bacteria) derived from Greek means
True bacteria
False bacteria
Recent bacteria
Ancient bacteria

21. Who coined the term Animalcules for microorganisms like Bacteria and protozoa?
Robert Koch
Louis Pasteur
Alexander Fleming
Leeuwenhoek

22. Who discovered the bacteria causing tuberculosis and also developed various techniques of media preparation and maintenance of pure culture?
Robert Koch
Louis Pasteur
Alexander Fleming
Leeuwenhoek

23. Which of the following statement is incorrect regarding germ theory of diseases postulated by Robert Koch?
A specific organism can always be found in association with a given disease
The organism can be isolated and grown in pure culture in the laboratories
The pure culture cannot produce the disease when inoculated into susceptible animal however the causative organism isolated from pure culture can do so.
It is possible to recover the organism in pure culture from the experimentally infected animals.

24. Which of the following structure is not present in all the bacteria?
Cell membrane
Chromatin bodies
Ribosomes
Capsule

25. The size of Spirochete is
0.1 -600 um
100-200 nm
500 um
0.75-1.25 um

26. E. coli and example of entrobacteriace is important for causing diarrheal diseases its size is:
0.1-600 um
100-200 nm
1.1-1.5 um (width) 2.0-6.0 um (length)
0.75-1.25 um

27. In bacterial categories the bacteria smaller in number are
Gram-ive bacteria
Gram-ive bacteria
Ancient bacteria
Gram +ive bacteria

28. Germ theory of disease has ______ postulates
3
5
4
6

29. Some bacteria ranging occasionally a size of 500 ?m in length are
Escherichia coli
Spirochetes
Mycoplasma
Epulopiscuim

30. Coccobacillus has a shape similar to
Diplobacillus
Sarcina
Egg
None of these

31. The first bacterium isolated was
Coccus
Bacillus
Vibrio
Spirochete

32. Which of the following bacteria are thick rigid and spiral?
Vibrio
Spirillum
Spirochete
Coccus

33. Coccus
Diplococci
Octococci
Tetrad
Sarcina

34. Which of the following has a chain arrangement?
Streptobacillus
Streptococci
Staphylococci
Both A and B

35. Which of the following bacteria do not have flagella commonly?
Cocci
Bacilli
Streptobacilli
Vibrio

36. Flagella originate from
Cell membrane
Cell wall
Capsule
Basal body

37. A bacterium with tuft of flagella at both poles is called
Lophotrichus
Monotrichous
Peritrichous
Amphitrichous

38. Which of the following structure primarily helps in attachment of bacteria on various surfaces?
Flagella
Pili
Both of these
None of these

39. Which of the following structure provides greater pathogenicity to the bacteria?
Capsule
Slime
Cell Wall
Cell membrane

40. Cell wall is absent in
Cocci
Bacilli
Mycobacterium
Mycoplasma

41. Cell wass of Archaeobacteria does not contain
Peptidoglycan
Proteins
Glycoproteins
Polysaccharides

42. Gram positive bacteria appear
Purple
Red
Pink
Blue

43. Extremely long molecule of DNA that is tightly folded to fit inside the cell component is called
Nucleus
Chromosome
Chromatid
Chromatin body

44. Which of the following contains genes for drug and disease resistance in bacteria?
Necleotide
Plasmid
Mesosome
Ribosome

45. The common waste material in bacteria is
Glycogen
Lactic acid
Ammonia
Urea

46. Example of bacteria requiring low concentration of oxygen is
Campylobactor
spirocheta
E-coli
Pseudomonas

47. Purple non-sulphur bacteria is an example of
Heterotrophic bacteria
Chemosynthetic bacteria
Photosynthetic bacteria
Saprotrophic bacteria

48. Those bacteria which are fully dependent upon their host for nutrition are called
Heterotrophic bacteria
Chemosynthetic bacteria
Saprophytic bacteria
Parasitic bacteria

49. Nitrifying bacteria are the examples of
Hetrotrophic bacteria
Chemosynthetic bacteria
Saprophytic bacteria
Parasitic bacteria

50. E. coli and example of
Aerobic bacteria
Anaerobic bacteria
Facultative bacteria
Microaerophilic