EASY PSC | 022/2023 - Junior Scientific Assistant Answer Key

Question 1

According to quantum mechanics, it is impossible to precisely and simultaneously specify both the linear momentum and position of a particle. This principle is known as :

A

Pauli’s antisymmetric principle

B

Hund’s principle of maximum spin multiplicity

C

Heisenberg’s uncertainty principle

D

Aufbau principle

Question 2

The Schrödinger equation consists of an energy operator known as :

A

Hermitian

B

Hamiltonian

C

Wave function

D

Legendre

Question 3

The energy required to remove the outermost or valence electron from the isolated gaseous atom is called the first ionization energy. Which of the following elements has the lowest ionization energy?

A

Li

B

Be

C

D

F

Question 4

Which of the following is in correct order of electro negativity values in Pauling’s scale?

A

Cl > Br > I > F

B

F > Cl > I > Br

C

F > Cl > Br > I

D

I > Br > F > Cl

Question 5

In quantitative chemical analysis, the term precision refers to :

A

Accurate result

B

Theoretical result

C

Abnormal result

D

Reproducible result

Question 6

Which of the following radiation is employed to study vibrational spectrum of a molecule?

A

Infrared radiation

B

Microwave radiation

C

Ultraviolet radiation

D

X-ray

Question 7

In order to record the proton NMR spectrum, which of the following compound is used as reference :

A

Tetramethylsilane

B

Dimethyl sulphoxide

C

D₂O

D

CDCl₃

Question 8

Paper chromatography is an example of :

A

Adsorption chromatography

B

Ion exchange chromatography

C

High Performance liquid chromatography

D

Partition chromatography

Question 9

The analytical technique that involves observing the change in weight of the substance as a function of temperature is called :

A

Mass spectrometry

B

Differential scanning calorimetry

C

Thermogravimetry

D

Differential thermal analysis

Question 10

For the coagulation of negatively charged sol As₂S₃ , which of the following species will be more effective?

A

Na⁺

B

Cl⁻

C

Al³⁺

D

Au

Question 11

Gold number of A, B, C, and D are 0.13, 0.013, 0.003 and 0.31. The order of protective power of these is :

A

A > B > C > D

B

C > B > A > D

C

D > A > B > C

D

None of the above

Question 12

Considering various theories of adsorption of gases on solids, which of the following is incorrect :

A

Langmuir isotherm is based on monolayer adsorption

B

BET isotherm is based on multilayer adsorption

C

Freundlich isotherm is of empirical nature

D

Langmuir isotherm is of empirical nature

Question 13

The gas that is known to damage the ozone layer in stratosphere is :

A

HCl

B

CN₃CH

C

CF₂Cl₂

D

Pb(C₂H₅)₄

Question 14

The disease itai-itai is caused by pollution due to :

A

Hg

B

Cd

C

Pb

D

DDT

Question 15

Eutrophication causes :

A

Air pollution

B

Water pollution

C

Soil pollution

D

Noise pollution

Question 16

Among the following, the main pollutant of leather tanneries is :

A

Mercury

B

Lead

C

Cadmium

D

Chromium

Question 17

Which one of the following is a greenhouse gas?

A

O₂

B

N₂

C

He

D

O₃

Question 18

The common scientific acoustic unit of sound measurement to study noise pollution is :

A

Candela

B

Decibel

C

Lumen

D

Hertz

Question 19

Which of the following species attacks haemoglobin to form carboxyhaemoglobin thereby causing poisoning effect?

A

CO₂

B

HCOOH

C

CO

D

C₂H₅OH

Question 20

The polycyclic aromatic hydrocarbon, benzo (α) pyrene is known for its :

A

Medicinal use as a chelating agent

B

Carcinogenic activity

C

Radioactivity

D

Use in artificial photosynthesis

Question 21

The organic load of the water body can be expressed in terms of BOD, which refers to :

A

The degree of microbially mediated oxygen consumption in water

B

The degree of chemically mediated oxygen consumption in water

C

The total organic carbon content in water

D

The total dissolved oxygen in water

Question 22

The commonly called black lung disease is also known as :

A

Byssinosis

B

Silicosis

C

Asbestosis

D

Pneumoconiosis

Question 23

Which one of the following is not matching with the principles of green chemistry?

A

It is better to prevent waste than to clean up waste after it is formed during a chemical reaction

B

Chemical products should be designed to preserve efficacy of the function while reducing toxicity

C

The use of auxiliary substances like solvents, separating agents is highly recommended

D

Synthetic methods should be designed to maximise the incorporation of all materials used in the process into the final product

Question 24

Which one of the following statements on water is wrong?

A

Water is regarded as a green solvent

B

Heavy metal containing chemicals cannot be dissolved in water

C

Water molecule has polar nature with a net dipole moment

D

Hydrogen bonding is important that helps to hold water molecules together in its liquid and solid state

Question 25

Microwave assisted organic reactions have the advantage of :

A

Faster reaction rates

B

Can be easily Scaled-up

C

Prevention of solvent evaporation

D

Any type of containers can be used

Question 26

The dye which is commonly used as a fixative in an electron microscope :

A

Ethidium bromide

B

Osmium tetroxide

C

Acridine orange

D

Safranin

Question 27

Which type of chromatographic technique is employed for the purification of large biomolecules of nucleic acids and proteins?

A

FPLC

B

HPLC

C

TLC

D

None of the above

Question 28

RNA can be analyzed by which of the following blotting technique?

A

Northern blotting

B

Western blotting

C

Southern blotting

D

None of the above

Question 29

Which staining method is used to identify DNA in specimens?

A

Volutin staining

B

Feulgen staining

C

Negative staining

D

Both A) and C)

Question 30

The annealing temperature in a PCR reaction usually ranges from :

A

75-80°C

B

35-45°C

C

55-60°C

D

90-100°C

Question 31

Identify the correct statement among the following :
(i) Addition of Lactobacillus cremoris in Swiss cheese results in eye formation and flavor enhancement
(ii) Kimchi is a fermented fish product
(iii) Idli batter fermentation is favoured by Leuconostoc mesenteroides and streptococcus faecalis
(iv) Shrikhand is a fermented milk product produced by Rhizopus oryzae

A

(iii)

B

(i) and (ii)

C

(i) and (iv)

D

(iv)

Question 32

The intestinal bacteria in infants commonly used as probiotic :

A

Streptococcus thermophilus

B

Helicobacter

C

Bifidobacteria

D

Bacillus pumilus

Question 33

Which among the statement is correct?

A

The codex guidelines for HACCP has eight principles

B

Critical control point aims at preventing physical chemical and biological hazards in food

C

National academy of sciences is an authority on food safety

D

All the above

Question 34

Bacillus coagulans causes –––––––––– type of spoilage in canned foods.

A

Hydrogen swell

B

TA spoilage

C

Sulfide spoilage

D

Flat sour spoilage

Question 35

“Sweating” is a type of food preservation in which?

A

Moisture is readded to a desired level

B

Moisture is reduced

C

Moisture is increased

D

None of the above

Question 36

Which among the following is an example for enveloped virus?

A

Herpes virus

B

Adeno virus

C

Tobacco mosaic virus

D

All the above

Question 37

Which among the following is a method for cultivation of anaerobic bacteria?

A

Lawn culture

B

Roll tube method

C

Stab culture

D

All the above

Question 38

Which genera of archaea lacks cell wall and resembles like mycoplasma?

A

Methanopyrus

B

Thermoplasma

C

Ferroplasma

D

Both B) and C)

Question 39

An example for endospore forming bacteria :

A

Bacillus

B

Sporosarcina

C

Thermoactinomyces

D

All the above

Question 40

Which among the following is an example for chemolithotrophic microbe?

A

Nitrosomonas

B

Halobacterium salinarum

C

Prochloron

D

All the above

Question 41

Which among the following is an example for sulphur reducing bacteria?

A

Archaeoglobus

B

Thiobacillus

C

A) and D)

D

Desulfococcus

Question 42

The production of antibiotics by one microorganism that inhibit or kill a susceptible microbe is an example for which types of microbial interaction:

A

Amensalism

B

Parasitism

C

Competition

D

None of the above

Question 43

Which algae causes Florida red tide bloom?

A

Spirogyra

B

Karenia brevis

C

Palmaria palmata

D

Ulothrix

Question 44

Biological removal of dissolved organic matter is done in which stage of waste water treatment?

A

Primary

B

Secondary

C

Tertiary

D

A) and B)

Question 45

––––––––––– is an airborne pathogen uniquely adapted to internal environment.

A

Puccinia triticina

B

Salmonella enteritidis

C

Salmonella typhimurium

D

Legionella pneumophila

Question 46

Which type of bioremediation technique is commonly used for removal of gaseous pollutants?

A

Bioventing

B

Biofilters

C

Biopiles

D

None of the above

Question 47

Which of the following indicates the steps in biogas production?

A

Hydrolysis – acetogenesis – acidogenesis – methanogenesis

B

Hydrolysis – acidogenesis – acetogenesis – methanogenesis

C

Acidogenesis – hydrolysis – acetogenesis – methanogenesis

D

Acidogenesis – acetogenesis – hydrolysis – methanogenesis

Question 48

Which species of earthworm is commonly employed in vermicomposting?

A

Eisenia foetida

B

Perionyx excavates

C

Lumbricus terrestris

D

Both A) and B)

Question 49

Which among the following is a hydrocarbon degrading bacteria?

A

Alcanivorax

B

Oleispira

C

Marinobacter

D

All the above

Question 50

Which among the following is a genetically engineered super bug utilized in petroleum biodegradation?

A

Pseudomonas putida

B

Bacillus cereus

C

Acetobacter

D

None of the above

Question 51

A Non-protein amino acid :

A

Ornithine

B

Tyrosine

C

Arginine

D

Proline

Question 52

Purity of isolated proteins is checked by :

A

Column chromatography

B

Mass spectrometry

C

Ammonium sulphate precipitation

D

Dialysis

Question 53

Nature of peritrichous flagella:

A

A single flagella located at one polar end

B

Flagella distributed all over body

C

A Bunch of flagella at two polar ends

D

A bunch of flagella at one end

Question 54

A plant geneticist observed a white branch on an otherwise green plant and on crossing the flowers produced on the white branch with pollen produced on the green branch all the progeny was found to be white. On reciprocal crosses all progeny were found to be green. Then, which among the statements are true :

A

The white branch was the result of a mutation in the chloroplast DNA

B

The white branch is the result of a mutation in the nuclear DNA

C

White mutation is dominant to green

D

Green and white are co dominant

Question 55

Which one is soil borne bacterial disease?

A

Leptospirosis

B

Brucellosis

C

Cholera

D

Salmonellosis

Question 56

Immunity obtained through colostrum is :

A

Natural passive immunity

B

Natural active immunity

C

Artificial passive immunity

D

Artificial active

Question 57

Which among is a neuromuscular autoimmune disease?

A

Rheumatoid arthritis

B

Pernicious anemia

C

Crohn’s disease

D

Myasthenia gravis

Question 58

Which of the following radiation have longest wavelength?

A

IR radiation

B

X-rays

C

Micro waves

D

Radio waves

Question 59

A researcher isolated amylase from the pancreas of an experimental rat and 20 μl of the enzyme preparation showed an activity of 0.5 Units when allowed to react for 1 minute. The concentration of the protein in the enzyme preparation was 0.25 mg/ml. Find out the specific activity of the enzyme preparation?

A

0.1 Units/mg

B

1 Unit/mg

C

10 Units/mg

D

100 Units/mg

Question 60

Atmospheric pressure is measured by :

A

Polarography

B

Fluorimetry

C

Densitometry

D

Manometry

Question 61

Carnegie 20 is :

A

Transposon vector of Saccharomyces

B

Transposon vector of E.coli

C

Transposon vector of Bacillus spp

D

Transposon vector of Drosophila

Question 62

Kleonw fragment of DNA polymerase I lack :

A

3’-5’ exonuclease activity

B

3’-5’ polymerase activity

C

5’-3’ exonuclease activity

D

5’-3’ polymerase activity

Question 63

Which among the following is an expression vector?

A

pUC 18

B

pBR 322

C

pCambia

D

pET

Question 64

T4 DNA ligase is capable of :

A

Stick end ligation only

B

Blunt end ligation only

C

Both stick and blunt end ligation

D

None of the above

Question 65

Two statements are given below. Analyse the statements and select the correct answer :
(a) Blue white colony selection using pUC recombinants work by alpha complementation
(b) Blue white colony selection requires a medium with X gal and IPTG

A

Both (a) and (b) are correct and (a) is the correct reason of (b)

B

Both (a) and (b) are correct and (b) is the correct reason of (a)

C

(a) is correct and (b) is wrong

D

(a) is wrong and (b) is correct

Question 66

First amino acid commercially produced by fermentation :

A

Glutamic acid

B

Phenyl alanine

C

L-Lysine

D

Aspartic acid

Question 67

Which among is considered as GRAS status?

A

Bacillus

B

E. coli

C

Lactobacillus

D

Penicillium

Question 68

BOD used for the measurement of :

A

Atmospheric pollution

B

Nuclear pollution

C

Sewage pollution

D

Thermal pollution

Question 69

The gas that combines with water to form acid rain :

A

Sulphur dioxide

B

Carbon dioxide

C

Carbon monoxide

D

Hydrogen sulphide

Question 70

Microorganisms indigenous to a given ecosystem are called :

A

Zymogenous

B

Autochthonous

C

Allochthonous

D

Autogenous

Question 71

The term ecosystem was proposed by :

A

Carl Mobino

B

A. Tansley

C

E. Odum

D

E. Clement

Question 72

An animal viral vector :

A

CMV

B

TMV

C

SV40

D

Gemini

Question 73

An edible vaccine for foot and mouth disease :

A

Banana

B

Tomato

C

Potato

D

Sugar beet

Question 74

In which format sequences submitted in Blast server?

A

FASTA

B

FISTA

C

MmCIF

D

PDB file format

Question 75

Which of the following is a protein data base?

A

DDBJ

B

EMBL

C

Gen Bank

D

PIR

Question 76

Which of the following will exhibit Tyndall effect?

A

Copper Sulphate solution

B

Water

C

Sugar Solution

D

Milk

Question 77

What is an Isotonic solution?

A

Solutions with different osmotic pressure

B

Solutions with same vapour pressure

C

Solutions with same osmotic pressure

D

Solutions with different vapour pressure

Question 78

The semi-permeable membrane used for carrying reverse osmosis is made up of –––––––––– material.

A

Potassium nitrate

B

Cellulose acetate

C

Parchment membrane

D

Cell membrane

Question 79

If 125mL of water is added to 250mL of 0.5M potassium sulphate solution, what will be the molarity of the diluted solution :

A

0.65M

B

0.75M

C

0.50M

D

0.33M

Question 80

Mole fraction is expressed as :

A

N/n

B

n/N

C

n(n+N)

D

N(n+N)

Question 81

Name the primary substance used in the vulcanization of rubber :

A

Sulphur

B

Phosphorus

C

Isoprene

D

Lead

Question 82

When you perform Fehling’s test, which among the following will give a positive result?

A

Sucrose

B

Glucose

C

Lipids

D

Proteins

Question 83

–––––––––– is the sugar molecule present in fruits.

A

Sucrose

B

Lactose

C

Fructose

D

Galactose

Question 84

Which of the following will influence Protein folding?

A

pH

B

Solvent

C

Salt Concentration

D

All the above

Question 85

–––––––––– is the base not present in DNA.

A

Adenine

B

Uracil

C

Thymine

D

Guanine

Question 86

Which bacterial cell wall has a huge percentage of Teichoic acid?

A

Gram positive

B

Gram negative

C

Both Gram positive and Gram negative

D

Gram Neutral

Question 87

Which of the following is not an indicator of water pollution?

A

Shigella dysenteriae

B

Streptococcus pyogenes

C

Clostridium difficile

D

Salmonella enteriditis

Question 88

Food preservation is carried out through cold sterilization, this involves :

A

Radiation

B

Lyophilization

C

Dehydration

D

Refrigeration

Question 89

Pasteurization is the process of heating milk :

A

Above 500 degree Celsius

B

Above 1000 degree Celsius

C

Above boiling point

D

Below boiling point

Question 90

Name the equipment used for the sterilization of the media after its preparation :

A

Incubator

B

Autoclave

C

Laminar air flow chamber

D

Inoculum needle

Question 91

Which of the following is called the particulate pollutant?

A

Ethylene

B

Flyash

C

Radon

D

Ozone

Question 92

–––––––––– contaminations lead to Mina Mata disease.

A

Mercury

B

Lead

C

Copper

D

Cadmium

Question 93

Which of the following can significantly control global warming?

A

Increasing Solid waste

B

Increasing fossil fuel consumption

C

Burning human generated waste

D

Reducing fossil fuel consumption

Question 94

Which of the following is an exsitu conservation method for endangered species?

A

Cryopreservation

B

Biosphere reserves

C

Wildlife sanctuaries

D

National Parks

Question 95

Which of the following happens naturally due to aging of lakes?

A

Biomagnification

B

Mesotrophic

C

Eutrophication

D

Oligotrophic

Question 96

–––––––––– described cell in a dead cork tissue.

A

Louis Pasteur

B

Anton Von Leeuwenhoek

C

Hans Jensen

D

Robert Hook

Question 97

Electron Microscope can provide magnification upto :

A

40X

B

4,000X

C

40,000X

D

400,000X

Question 98

Which chromatography method involves a technique in which the stationary phase is held in a narrow tube and the mobile phase is forced through it under pressure?

A

Planar

B

Gas

C

Thin layer

D

Column

Question 99

Burning of wastes is not an acceptable practice of Solid waste management because :

A

It is not cost effective

B

It involves lots of space

C

It requires modern technology

D

It causes environmental issues

Question 100

Enzymes used to cut DNA molecule in rDNA technology is :

A

Phosphatase

B

Ligase

C

Ribonuclease

D

Restriction enzymes