Biology Mcqs Test Preparation for ECAT & MCAT - Set 2

1)   Sebum produced from sebaceous glands in a mammal helps in

a. Protection against micro organisms
b. Temperature regulation
c. Excretion
d. All of these
Answer  Explanation 

ANSWER: Protection against micro organisms

Explanation:
No explanation is available for this question!


2)   Biological molecules (proteins) which catalyze a biochemical reaction and remain unchanged after completion of reaction are called

a. Cofactor
b. Coenzymes
c. Activator
d. Enzymes
Answer  Explanation 

ANSWER: Enzymes

Explanation:
No explanation is available for this question!


3)   Which statement about enzyme is incorrect:

a. Some of them consist solely of protein with no non protein part.
b. They catalyze a chemical reaction without being utilized.
c. All enzymes are fibrous Proteins.
d. They without their cofactor are called apoenzyme.
Answer  Explanation 

ANSWER: All enzymes are fibrous Proteins.

Explanation:
No explanation is available for this question!


4)   In which of the following location enzymes controlling cellular respiration are present?

a. Nucleus
b. Chlorophast
c. Milochondria
d. Ribosome
Answer  Explanation 

ANSWER: Milochondria

Explanation:
No explanation is available for this question!


5)   An activated enzyme consisting of polypeptide chain and a cofactor is called:

a. Apoenzyme
b. Holoenzyme
c. Activated enzyme
d. Both b and c
Answer  Explanation 

ANSWER: Both b and c

Explanation:
No explanation is available for this question!


6)   Which one forms the raw material for coenzymes?

a. Vitamins
b. Carbohydrates
c. Proteins
d. Metals
Answer  Explanation 

ANSWER: Vitamins

Explanation:
No explanation is available for this question!


7)   A cofactor made of inorganic ion which is detachable is called

a. Prosthetic group
b. Coenzyme
c. Activator
d. Cofactor
Answer  Explanation 

ANSWER: Activator

Explanation:
No explanation is available for this question!


8)   Enzymes _________ the activation energy of a chemical reaction

a. Increases
b. Increases
c. Does not effect
d. Increases or decreases depending upon individual enzyme
Answer  Explanation 

ANSWER: Increases

Explanation:
No explanation is available for this question!


9)   A three dimensional dcavity bearing a specific charge by which the enzyme reacts with its substrate is called

a. Active site
b. Binding site
c. Catalytic site
d. Allosteric site
Answer  Explanation 

ANSWER: Active site

Explanation:
No explanation is available for this question!


10)   Which step causes activation of catalytic site of an enzyme?

a. Change in pH of the surroundings.
b. Formation of Enzyme Susstrate complex.
c. Change in the charge of the active site.
d. Change in temperature
Answer  Explanation 

ANSWER: Formation of Enzyme Susstrate complex.

Explanation:
No explanation is available for this question!


11)   Lock and Key model was proposed by

a. Emil Fischer
b. Koshland
c. Robin Williams
d. Rudolph Virchow
Answer  Explanation 

ANSWER: Emil Fischer

Explanation:
No explanation is available for this question!


12)   Which statement is incorrect about Lock and Key Model?

a. Specific enzyme can transform only a specific substrate
b. Active site of an enzyme is a non flexible structure.
c. Active site does not change before during or even after the reaction.
d. It explains the mechanism of every chemical reaction.
Answer  Explanation 

ANSWER: It explains the mechanism of every chemical reaction.

Explanation:
No explanation is available for this question!


13)   The rate of reaction is directly proportional to the concentration of an enzyme which statement is incorrect in this respect:

a. Increase in enzyme molecule increases the available active sites.
b. This relation is for unlimited time period with unlimited enzyme concentration
c. If the concentration is doubled the rate will become two fold.
d. None of these.
Answer  Explanation 

ANSWER: This relation is for unlimited time period with unlimited enzyme concentration

Explanation:
No explanation is available for this question!


14)   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

a. Enzymes get denatured at higher substrate conc.
b. Rate of reaction is indirectly proportional to substrate concentration at this point.
c. All the active sites on enzyme molecule are occupied.
d. None of these.
Answer  Explanation 

ANSWER: All the active sites on enzyme molecule are occupied.

Explanation:
No explanation is available for this question!


15)   If more substrate to already occurring enzymatic reaction is added more enzyme activity is seen because:

a. There is probably more substrate present than there is enzyme.
b. There is probably more enzayme available than there is substrate.
c. There is probably more product present than there is either substrate or enzyme.
d. The enzyme substrate complex is probably failing to form during the reaction.
Answer  Explanation 

ANSWER: There is probably more enzayme available than there is substrate.

Explanation:
No explanation is available for this question!


16)   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:

a. Saturation
b. Denaturation
c. Composition
d. Inhibition
Answer  Explanation 

ANSWER: Saturation

Explanation:
No explanation is available for this question!


17)   The active site of an enzyme:

a. Never changes
b. Forms no chemical bond with substrate
c. Determined by structure and the specificity of the enzyme.
d. They are non specific in their action.
Answer  Explanation 

ANSWER: Determined by structure and the specificity of the enzyme.

Explanation:
No explanation is available for this question!


18)   Excessive increase in temperature of medium causes the enzyme molecule to

a. Activate
b. Unaffected
c. Denatured
d. None of these.
Answer  Explanation 

ANSWER: Denatured

Explanation:
No explanation is available for this question!


19)   Extreme change in pH results in:

a. Change in ionization of amino acids at the active site of the enzyme.
b. Change in the ionization of the substrate.
c. Denaturation of the enzyme
d. Increase in the reaction rate.
Answer  Explanation 

ANSWER: Denaturation of the enzyme

Explanation:
No explanation is available for this question!


20)   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

a. Co-enzyme
b. Blocker
c. Inhibitor
d. Cofactor
Answer  Explanation 

ANSWER: Inhibitor

Explanation:
No explanation is available for this question!


21)   Inhibitors which block the enzyme by forming weak bond are called

a. Competitive inhibitors.
b. Non-competitive inhibitors
c. Irreversible inhibitors.
d. Both a and b
Answer  Explanation 

ANSWER: Both a and b

Explanation:
No explanation is available for this question!


22)   A substance which binds at the active site of the enzyme but does not result in the formation of the products is called:

a. Irreversible inhibitor
b. Reversible inhibitor
c. Competitive inhibitor
d. Non-competitive inhibitor
Answer  Explanation 

ANSWER: Competitive inhibitor

Explanation:
No explanation is available for this question!


23)   The structure of an enzyme is altered by:

a. Irreversible inhibitor
b. Reversible inhibitor
c. Competitive inhibitor
d. Non-competitive inhibitor
Answer  Explanation 

ANSWER: Irreversible inhibitor

Explanation:
No explanation is available for this question!


24)   Malonic acid is an example of:

a. Irreversible inhibitor
b. Reversible inhibitor
c. Competitive inhibitor
d. Non-competitive inhibitor
Answer  Explanation 

ANSWER: Competitive inhibitor

Explanation:
No explanation is available for this question!


25)   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.

a. increase in concentration of enzyme
b. increase in concentration of substrate
c. increase in pH
d. increase in temperature
Answer  Explanation 

ANSWER: increase in concentration of enzyme

Explanation:
No explanation is available for this question!


26)   The word Archaeobacteria (a division of bacteria) derived from Greek means

a. True bacteria
b. False bacteria
c. Recent bacteria
d. Ancient bacteria
Answer  Explanation 

ANSWER: Ancient bacteria

Explanation:
No explanation is available for this question!


27)   Who coined the term Animalcules for microorganisms like Bacteria and protozoa?

a. Robert Koch
b. Louis Pasteur
c. Alexander Fleming
d. Leeuwenhoek
Answer  Explanation 

ANSWER: Leeuwenhoek

Explanation:
No explanation is available for this question!


28)   Who discovered the bacteria causing tuberculosis and also developed various techniques of media preparation and maintenance of pure culture?

a. Robert Koch
b. Louis Pasteur
c. Alexander Fleming
d. Leeuwenhoek
Answer  Explanation 

ANSWER: Robert Koch

Explanation:
No explanation is available for this question!


29)   Which of the following statement is incorrect regarding germ theory of diseases postulated by Robert Koch?

a. A specific organism can always be found in association with a given disease
b. The organism can be isolated and grown in pure culture in the laboratories
c. The pure culture cannot produce the disease when inoculated into susceptible animal however the causative organism isolated from pure culture can do s
d. It is possible to recover the organism in pure culture from the experimentally infected animals.
Answer  Explanation 

ANSWER: The pure culture cannot produce the disease when inoculated into susceptible animal however the causative organism isolated from pure culture can do s

Explanation:
No explanation is available for this question!


30)   Which of the following structure is not present in all the bacteria?

a. Cell membrane
b. Chromatin bodies
c. Ribosomes
d. Capsule
Answer  Explanation 

ANSWER: Capsule

Explanation:
No explanation is available for this question!


31)   The size of Spirochete is

a. 0.1 -600 um
b. 100-200 nm
c. 500 um
d. 0.75-1.25 um
Answer  Explanation 

ANSWER: 500 um

Explanation:
No explanation is available for this question!


32)   E. coli and example of entrobacteriace is important for causing diarrheal diseases its size is:

a. 0.1-600 um
b. 100-200 nm
c. 1.1-1.5 um (width) 2.0-6.0 um (length)
d. 0.75-1.25 um
Answer  Explanation 

ANSWER: 1.1-1.5 um (width) 2.0-6.0 um (length)

Explanation:
No explanation is available for this question!


33)   In bacterial categories the bacteria smaller in number are

a. Gram-ive bacteria
b. Eubacteria
c. Ancient bacteria
d. Gram +ive bacteria
Answer  Explanation 

ANSWER: Ancient bacteria

Explanation:
No explanation is available for this question!


34)   Germ theory of disease has ______ postulates

a. 3
b. 5
c. 4
d. 6
Answer  Explanation 

ANSWER: 4

Explanation:
No explanation is available for this question!


35)   Coccobacillus has a shape similar to

a. Diplobacillus
b. Sarcina
c. Egg
d. None of these
Answer  Explanation 

ANSWER: Egg

Explanation:
No explanation is available for this question!


36)   The first bacterium isolated was

a. Coccus
b. Bacillus
c. Vibrio
d. Spirochete
Answer  Explanation 

ANSWER: Bacillus

Explanation:
No explanation is available for this question!


37)   Which of the following bacteria are thick rigid and spiral?

a. Vibrio
b. Spirillum
c. Spirochete
d. Coccus
Answer  Explanation 

ANSWER: Spirillum

Explanation:
No explanation is available for this question!


38)   A group of 8 cocci is called

a. Diplococci
b. Octococci
c. Tetrad
d. Sarcina
Answer  Explanation 

ANSWER: Sarcina

Explanation:
No explanation is available for this question!


39)   Which of the following has a chain arrangement?

a. Streptobacillus
b. Streptococci
c. Staphylococci
d. Both A and B
Answer  Explanation 

ANSWER: Both A and B

Explanation:
No explanation is available for this question!


40)   Which of the following bacteria do not have flagella commonly?

a. Cocci
b. Bacilli
c. Streptobacilli
d. Vibrio
Answer  Explanation 

ANSWER: Cocci

Explanation:
No explanation is available for this question!


41)   Flagella originate from

a. Cell membrane
b. Cell wall
c. Capsule
d. Basal body
Answer  Explanation 

ANSWER: Basal body

Explanation:
No explanation is available for this question!


42)   A bacterium with tuft of flagella at both poles is called

a. Lophotrichus
b. Monotrichous
c. Peritrichous
d. Amphitrichous
Answer  Explanation 

ANSWER: Amphitrichous

Explanation:
No explanation is available for this question!


43)   Which of the following structure primarily helps in attachment of bacteria on various surfaces?

a. Flagella
b. Pili
c. Both of these
d. None of these
Answer  Explanation 

ANSWER: Pili

Explanation:
No explanation is available for this question!


44)   Which of the following structure provides greater pathogenicity to the bacteria?

a. Capsule
b. Slime
c. Cell Wall
d. Cell membrane
Answer  Explanation 

ANSWER: Slime

Explanation:
No explanation is available for this question!


45)   Cell wall is absent in

a. Cocci
b. Bacilli
c. Mycobacterium
d. Mycoplasma
Answer  Explanation 

ANSWER: Mycoplasma

Explanation:
No explanation is available for this question!


46)   Cell wass of Archaeobacteria does not contain

a. Peptidoglycan
b. Proteins
c. Glycoproteins
d. Polysaccharides
Answer  Explanation 

ANSWER: Peptidoglycan

Explanation:
No explanation is available for this question!


47)   Gram positive bacteria appear

a. Purple
b. Red
c. Pink
d. Blue
Answer  Explanation 

ANSWER: Purple

Explanation:
No explanation is available for this question!


48)   Extremely long molecule of DNA that is tightly folded to fit inside the cell component is called

a. Nucleus
b. Chromosome
c. Chromatid
d. Chromatin body
Answer  Explanation 

ANSWER: Chromatin body

Explanation:
No explanation is available for this question!


49)   The common waste material in bacteria is

a. Glycogen
b. Lactic acid
c. Ammonia
d. Urea
Answer  Explanation 

ANSWER: Lactic acid

Explanation:
No explanation is available for this question!


50)   Example of bacteria requiring low concentration of oxygen is

a. Campylobactor
b. spirocheta
c. E-coli
d. Pseudomonas
Answer  Explanation 

ANSWER: Campylobactor

Explanation:
No explanation is available for this question!