MCQ Biology - Learning Biology through MCQs

Biology Multiple Choice Questions and Answers for Different Competitive Exams

Multiple Choice Questions on Mode of Action of Antibiotics

MCQ on Mode of Action of Antibiotics
1. Penicillin causes bacterial cell lyses by inhibiting the enzyme that catalyzes cross- linking of peptidoglycan chains of the bacterial cell wall. The enzyme is
a) enolpyruvyl transferase
b) transglycolase
c) transpeptidase
d) ribonuclease


2. Which of the following antibiotics blocks the first step of peptidoglycan cell wall synthesis by  inhibiting enzyme MurA?
a) Fosfomycin
b) Penicillin
c) Vancomycin
d) Bacitracin

3. Which of the following is a DNA gyrase inhibitor, thus disrupting bacterial DNA replication?
a) ciprofloxacin
b) Vancomycin
c) Chloramphenicol
d) Streptomycin

4. All the following drugs are bacterial cell wall synthesis inhibitors except
a)Vancomycin
b) Bacitracin
c) Fosfomycin
d) Rifamycin

5. All the following are protein synthesis inhibitors which binds to the 50S ribosomal subunit and blocks protein synthesis except
a) Streptomycin
b) Erythromycin
c) Cliindamycin
d) Chloramphenicol

6. Which of the following antibiotic inhibits transcription by binding DNA at the transcription initiation complex and preventing elongation of RNA chain by RNA polymerase?
a)Rifampicin
b) Streptomycin
c) Carbenicillin
d) Actinomycin D

7. This antibiotic binds to the D-ala residues preventing cross linking of cell wall strands by preventing the binding of cross linking enzyme. The antibiotic is  
a) Erythromycin
b) Vancomycin
c) Cephalosporin
d)Chloramphenicol

8. Which of the following is not a protein synthesis inhibitor by binding to 30 S small ribosomal subunit?
a) Kanamycin
b) Streptomycin
c) Erythromycin
d)Tetracycline

9. Which of the following antibiotic prevents bacterial transcription by directly binding to the bacterial RNA polymerase?
a) Rifampin
b) polymixin
c) Puromycin
d) Streptomycin

10. The antibiotic that prevents peptidoglycan synthesis by blocking the transport of peptidoglycan monomer is
a)Cephamycin
b) Cephalosporin
c) Bacitracin
d)Vancomycin
 Learn more:
Answers
1. c) transpeptidase
2. a) Fosfomycin
3. a) ciprofloxacin
4. d) Rifamycin
5. a) Streptomycin
6. d) Actinomycin D
7. b) Vancomycin
8. c) Erythromycin
9. a) Rifampin
10. c) Bacitracin
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Multiple Choice Questions on Cellular and Molecular Biology


1. What is the Best evidence that genes encode the amino acid sequence of proteins?
a) proteins are macromolecules
b) The amino acid sequence of polypeptide is changed by gene mutation
c) DNA serves as a template for RNA
d)mRNA is found in the ribosome

2. Which is not a characteristic of proteins?
a) waxes
b)albumins
c) carotenoids
d)Lecithin

3. The tRNA anticodon for the amino acid valine is CAA(reading 3’ to 5’). What is the mRNA codon for valine (reading 5’ to 3’)
a) TTG
b) GGU
c) CCA
d) UGG

4. The basis for the pairing of the two strand of DNA in the double helix is
Multiple Choice Questions on Cellular and Molecular Biology
a) covalent bonding
b) hydrogen bonding
c) hydrophobic interaction  
d) tertiary structure

5. Which of the following statements about the Krebs cycle is not true?
a) The Krebs cycle is linked to glycolysis by pyruvate
b) The Krebs cycle produces nucleotides such as NADH and FADH2
c) Citrate is an intermediate in the Krebs cycle
d) The Krebs cycle is the single greatest source of ATP in the cell

6. Which of the flowing is a correct association?
a)Polysome: group of Golgi complexes
b)Ribosome: electron transport chain
c)Lysosome: digestive enzyme for intracellular use
d)Mitochondria: transport materials from the nucleus to the cytoplasm

7. Which of the following statements about viruses is not true?
a)The protein coat of the virus does not enter a host bacterial cell
b)Their genetic material may be DNA or DNA
c)The virus may replicate in a bacterial host
d)The virus may replicate autonomously in the absence of a host

8.  Cells  that involved in active transport such as cells of the intestinal epithelium, utilize large quantities of ATP. In such cells, there are
a)many polyribosomes
b)many mitochondria
c)many lysosomes
d) high level of adenylate cyclise activity

9.  Which of the following statements regarding photosynthesis is not true?
a)The light cycle occurs only during exposure to light.
b)Red and blue are optimal for photosynthetic function
c)ATP is produced during the light cycle.
d)The dark cycle occurs only in the absence of light.

10. Which of the following process utilizes proofreading to increase its accuracy?
 a)transcription
b)DNA replication
c)recombination
d)electron transport
Answers
1. b) The amino acid sequence of polypeptide is changed by gene mutation
2. b)albumins
3. b) GGU
4. b) hydrogen bonding
5. d) The Krebs cycle is the single greatest source of ATP in the cell
6. c)Lysosome: digestive enzyme for intracellular use
7. d)The virus may replicate autonomously in the absence of a host
8. b)many mitochondria
9. d)The dark cycle occurs only in the absence of light.
10. b)DNA replication
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Multiple Choice Questions on Natural Resources


1. Which of the following is a non-renewable resource?
a) water
b) coal
c) soil
d) wildlife
2. Conventional energy refers to
a) Exhaustible energy sources in limited quantity
b) Inexhaustible energy sources in unlimited quantity
c) renewable energy resources
d)  none of these
3. Which of the following is an inorganic natural resource?
a) water
b) fossil fuels
c) plants
d) animals
4. Energy that is trapped in the form of organic matter is called
a) Conventional energy
b) Renewable energy
c) Biomass energy
d) Bioenergy
5. Which of the following is a renewable source of energy?
a) petroleum
b) nuclear fuel
c)  trees
d) coal
6. Which of the following is considered as conventional, inexhaustible source of energy?
a) thermal energy
b) hydropower
c) solar energy
d) wind energy
Multiple Choice Questions on Natural Resources

7. All are renewable resources except
a) soil fertility
b) rainfall
c) biological species
d) wildlife 
8. Fossil fuels include
a) coal and metals
b) coal, natural gas and oil
c) oil and minerals
d) oil, minerals and metals
9. Which of the following is not a conventional energy resource?
a) petrol
b) LPG
c) tidal energy
d) coal
10. Which of the following is an exhaustible renewable resource?
a) petroleum
b) tidal energy
c) coal
d) fresh water
Learn more:

Answers:
1. b) coal
2. a) Exhaustible energy sources in limited quantity
3. a) water
4. c) Biomass energy
5. c) trees
6. b) hydropower
7. c) biological species
8. b) coal, natural gas and oil
9. c) tidal energy
10. d) fresh water
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MCQ on Translocation of Water

1. Which of the following element is responsible for maintaining turgor?
a)Na
b)Ca
c)P
d)K
Show Answer


2. Why the tropical deciduous forest trees shed their leaves?
a)to prevent loss of water
b)to enhance the rate of absorption
c)to enhance rate of transpiration
d)to prevent loss of water

Show Answer
3. Which one of the following is produced during water stress and cause closure of stomata
a)Abscisic acid
b)cytokinin
c)Ethylene
d)Gibberellic acid

Show Answer
4. Which one of the following  plant would metabolism be hindered if the leaves are coated with wax on their upper surface?:
a) Hydrilla
b)Vallisnaria
c)Lotus
d)Pistia

Show Answer
5. Which one of the following is used for measuring the rate of transpiration
potometer
a)potometer
b)porometer
c)osmometer
d)None of these

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6. Stomata open at night and close during day time in
a) xerophytes
b)mesophytes
c)hydrophytes
d)epiphytes

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7. Phenyl Mercuric acetate (PMA) results in
a) killing of plants
b)reduced respiration
c)reduced transpiration
d)reduced transpiration

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8. Active K+ exchange mechanism for opening and closing stomata was given by:
a) Darwin
b)Levitt
c)Scarth
d)Khorana

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9. Which one explains ascent of sap
a)Cohesion theory
b)Mass flow
c)Malate hypothesis
d)Interfacial flow hypothesis

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10.The principal pathways by which water is translocated in angiosperms is
 a)xylem vessel system
b) sieve cells of phloem
c) xylem and phloem together
d)sieve tube members of phloem
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MCQ on Water Relations of Plants

1.The thin film of water covering the soil particles and held strongly by attractive forces, is called 
 a)hygroscopic 
 b)hydroscopic
 c)run away 
 d)capillary
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MCQ on Water Relations of Plants
2. Choose the correct sequence of events, when the plant wilts 
 a) endosmosis, deplasmolysis, temporary and permanent wilting
 b) exosmosis, deplasmolysis, temporary and permanent wilting 
 c) endosmosis, plasmolysis, temporary and permanent wilting 
 d) exosmosis, plasmolysis, temporary and permanent wilting
Show Answer
3. The term ‘water potential’ was coined by 
 a) Stephan Hales 
 b)Robert Hill 
 c)Lloyed 
 d)Slatyer and Taylor 
Show Answer
4. Osmotic pressure is highest in 
 a)mesophytes 
 b)halophytes 
 c)epiphytes 
 d)xerophytes
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5.Which one is semipermeable? 
 a)chloroplast 
 b)plasmalemma 
 c)Endoplasmic reticulam 
 d)cell wall
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6.Which one of the following is against concentration gradient?
 a)osmosis
 b)transpiration
 c)translocation 
 d)transpiration 
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7. DPD of a fully turgid cell is equal to 
 a)0
 b)2
 c)1 
 d)4
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8.The direction and the rate of water movement from cell to cell is based on
 a)diffusion pressure deficit(DPD) 
 b)plasmolysis 
 c)wall pressure 
 d)incipient plasmolysis
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9.The movement of water from one of the cortex cell to the adjacent one in roots is due to 
 a) chemical potential gradient 
 b) accumulation of inorganic salts in the cells 
 c) accumulation of organic compounds in the cells 
 d) water potential gradient
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10. DPD is equal to 
 a)OPX TP 
 b)OP+TP 
 c)OP-TP 
 d)TP-OP

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Multiple Choice Questions on Biomolecules

1.Number of essential elements in animals are
a)16
b)18
c)20
d)25
Multiple Choice Questions on Biomolecules - DNA
2. Cellular micromoleules are
a)amino acids, water, minerals, nucleotides and sugar
b) glycogen, amino acids, minerals and nucleotides
c)water, minerals, proteins and nucleotides
d)sugars, water, mineral, nucleotides an d proteins

3.The ratio between hydrogen and oxygen in a carbohydrate is
a)5:1
b)4:3
c)3:1
d)2:1

4.Which one is fat soluble vitamin?
a)vit A
b) vit D
c) vit E
d)All of these

5.A non reducing sugar is
a)glucose
b)sucrose
c)fructose
d)maltose

6.Which one is basic amino acid?
a)proline
b)arginine
c)proline
d)histidine

7. Which of the following protein has storage capacity?
a)glutenins
b)myosin
c)chondrin
d)keratin

8.Sweetest sugar is
a)frucose
b)glucose
c)mannose
d)lactose

9.Which one of the following is a reducing sugar?
a)galactose
b)gluconic acid
c)sucrose
d)b methyl galctoside

10.An organic substance bound to an enzyme and essential for its activity is called
 a)isoenzyme
b)coenzyme
c)holoenzyme
d)apoenzyme
Answers
1. d)25
2. a)amino acids, water, minerals, nucleotides and sugar
3. d)2:1
4.d)All of these
5. b)sucrose
6. b)arginine
7. a)glutenins
8. a)frucose
9. a)galactose
10. b)coenzyme
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MCQ on Dormancy and Seed germination

1. Dormancy is the
a) failure of a seed to germinate under favourable condition
b) failure of a seed to germinate under unfavourable condition
c) the ability of a seed to germinate under favourable condition
d) the ability of a seed to germinate under unfavourable condition
MCQ on Dormancy and Seed germination

2. Which of the following statement is true regarding dormancy?
a) Dormancy may be due to seed coats impermeability to CO2
b) Dormancy helps the seed to overcome unfavourable condition
c) Dormancy helps the seed to germinate during unfavourable condition
d) Dormancy may be due to soft fragile seed coat

3. Which of the following is a natural germination inhibitor that induces dormancy?
a) auxin
b) cytokinin
c) ABA
d) gibberellin

4. Some seeds enter dormancy when exposed to unfavourable condition for some time. Such dormancy is called  
a) immediate dormancy
b) primary dormancy
c) secondary dormancy
d) short term dormancy

5. Which of the following plant exhibit dormancy due to immature embryo?
a) Xanthium
b) Orchids
c) Hibiscus
d) Solanum

6. The process of weakening the seed coat to break dormancy is called
a) vernalization
b) scarification
c) photoperiodism
d) stratification

7. Photoblastic seeds are seeds
a) affected by light for germination
b) not affected by light for germination
c) independent of light for germination
d) affected by light and temperature for germination

8. Which is the pigment is involved in the germination of photoblastic seeds?
a) chlorophyll
b) carotenes
c) phytochromes
d) phaeophytin

9. Which of the following hormone is a dormancy inducer?
a) 2-4D
b) GA4
c) ABA
d) GA3
10. Which of the following is the structure in the seed coat that prevents water and O2 entry into seed thereby inducing dormancy?
a) strophiolar plug
b) pericarp
c) exocarp
d) epicarp
Answers:
1. b) failure of a seed to germinate under unfavourable condition
 2. b) Dormancy helps the seed to overcome unfavourable condition
3. c) ABA
4. c) secondary dormancy
5. b) Orchids
6. b) scarification
7.a) affected by light for germination
8. c) phytochromes
9. c) ABA
10. a) strophiolar plug
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