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Home Questions & Answer Science Questions & Answers Biology Questions & Answers

Biology Questions & Answers (Compiled from UPSC, SSC ,PSC ,IBPS previous question papers)

Choose the correct statement.
AReceptors do not produce graded potentials.
BNociceptors respond to changes in pressure.
CMeissner's corpuscles are thermoreceptors.
DPhotoreceptors in the human eye are depolarized during darkness and become hyperpolarized in response to the light stimulus.

Explanation:

Photoreceptors in the human eye are depolarized during darkness and become hyperpolarized in response to the light stimulus.

The partial pressure of oxygen in the alveoli of the lungs is
Aless than that of carbon dioxide
Bequal to that in the blood
Cmore than that in the blood

Dless than that in the blood
Explanation:

pO2 in Alveoli is 104, while in oxygenated blood, it is 95.

Which hormones do stimulate the production of pancreatic juice and bicarbonate?
AInsulin and glucagon
BAngiotensin and epinephrine
CGastrin and insulin
DCholecystokinin and secretin

Explanation:

Pancreatic juice rich in enzymes is secreted under influence of cholecystokinin, while pancreatic juice rich in bicarbonates is secreted under influence of secretin.

Match the stages of meiosis in Column-I to their characteristic features in Column-II and select the correct option using the codes given below :

Column-I Column-II

a. Pachytene (i) Pairing of homologous chromosomes

b. Metaphase I (ii) Terminalization of chiasmata -

c. Diakinesis (iii) Grossing-over takes place

d. Zygotenev (iV) Chromosomes align at equatorial plate
A(iv) (iii) (ii) (i)
B(iii) (iv) (ii) (i)

C(i) (iv) (ii) (iii)
D(ii) (iv) (iii) (i)

When cell has stalled DNA replication fork, which checkpoint should be predominantly activated?
ABoth G₂/M and M
BG₁/S
CG₂/M

DM
Explanation:

G2/M check point ensures that DNA Replication is complete and no error is left.

Which of the following describes the given graph correctly?
AExothermic reaction with energy A in absence of enzyme and B in presence of enzyme
BEndothermic reaction with energy A in presence of enzyme and B in absence of enzyme
CExothermic reaction with energy A in presence of enzyme and B in absence of enzyme

DEndothermic reaction with energy A in absence of enzyme and B in presence of enzyme.

Which of the following is the least likely to be involved in stabilizing the three-dimensional folding of most proteins?
AEster bonds

BHydrogen bonds
CElectrostatic interaction
DHydrophobic interaction
Explanation:

Ester bonds are formed in nucleic acids and lipids, but not proteins.

Oxidative phosphorylation is
Aformation of ATP energy released from electrons removed during substrate oxidation

Bformation of ATP by transfer of phosphate group from a substrate to ADP.
Coxidation of phosphate group in ATP
Daddition of phosphate group to ATP
Explanation:

Oxidative phosphorylation occurs when NADH⁺ + H⁺ or FADH₂ are oxidized and their electron enters in ETC creating proton gradient which finally produce ATP in F_0-F₁ particle.

Smooth muscles are
Avoluntary, spindle-shaped, uninucleate
Binvoluntary, fusiform, non-striated

Cvoluntary, multinucleate, cylindrical
Dinvoluntary, cylindrical, striated

In male cockroaches, sperms are stored in which part of the reproductive system?
AVas deferens
BSeminal vesicles

CMushroom glands
DTestes

Choose the correct statement.
AAll Pisces have gills covered by an operculum.
BAll mammals are viviparous.
CAll cyclostomes do not possess jaws and paired fins.

DAll reptiles have a three-chambered heart.

Match Column-I with Column-II for housefly classification and select the correct option using the codes given below :

Column-I Column-II

a. Family (i) Diptera

b. Order (ii) Arthropoda

c. Clsass (iii) Muscidae

d. Phylum (iv) Insecta
A(iv) (ii) (i) (iii)
B(iii) (i) (iv) (ii)

C(iii) (ii) (iv) (i)
D(iv) (iii) (ii) (i)

Which of the following sets of diseases is caused by bacteria?
AHerpes and influenza
BCholera and tetanus

CTyphoid and smallpox
DTetanus and mumps

The highest DDT concentration in aquatic food chain shall occur in
Aeel
Bphytoplankton
Cseagull

Dcrab
Explanation:

Bioamplification of nondegradable chemicals is seen as we move upwards in trophic level and thus in Sea gull (bird) level of DDT will be maximum.

A lake which is rich in organic waste may result in
Amortality of fish due to lack of oxygen

Bincreased population of aquatic organisms due to minerals
Cdrying of the lake due to algal bloom
Dincreased population of fish due to lots of nutrients
Explanation:

Lake with large amount of organic waste will increase BOD of water since microbes will use more Dissolved Oxygen to degrade organic matter

Which of the following National Parks is home to the famous musk deer or hangul?
ADachigam National Park, jammu & Kashmir

BKeibul Lamjao National Park, Manipur
CBandhavgrah National Park, Madhya Pradesh
DEaglenest Wildlife Sanctuary, Arunachal Pradesh

The principle of competitive exclusion was stated by
AVerhulst and Pear
BC. Darwin
CG. F. Gause

DMacArthur

Biochemical Oxygen Demand (BOD) may not be good index for pollution for water bodies receiving effluents from
Asugar industry
Bdomestic sewage
Cdairy industry
Dpetroleum industry

Match Column-I with Column-II and select the correct option using the codes given below:

Column-I Column-II

a. Citric acid (i) Trichoderma

b. Cyclosporin A (ii) Clostridium

c. Statins (iii) Aspergillus

d. Butyric (iv) Monascus
A(iii) (iv) (i) (ii)
B(iii) (i) (ii) (iv)
C(iii) (i) (iv) (ii)

D(i) (iv) (ii) (iii)

Among the following edible fishes, which one is a marine fish having rich source of omega-3 fatty acids?
AMackerel

Which of the following is correct regarding AIDS causative HIV?
AHIV does not escape but attacks the acquired immune response.

BHIV is enveloped virus containing one molecule of single-stranded RNA and one molecule of reverse transcriptase.
CHIV is enveloped virus that contains two identical molecules of single-stranded RNA and two molecules of reverse transcriptase.
DHIV is unenveloped retrovirus.
Explanation:

HIV attacks helper T cells and not try to hide from them

Interespecific hybridization in the mating of
Amore closely related individuals within same breed for 4-6 generations
Banimals within same breed without having common ancestors
Ctwo different related species

Dsuperior males and females of different breeds

DNA- dependent RNA polymerase catalyzes transcription on the strand of the DNA which is called the
Aantistrand
Btemplate strand

Ccoding strand
Dalpha strand

A molecule that can act as a genetic material must fulfill the traits given, except
Ait should provide the scope for slow changes that are required for evolution
Bit should be able to express itself in the form of 'Mendelian characters'
Cit should be able to generate its replica
Dit should be unstable structurally and chemicpally

Stirred-tank bioreactors have been designed for
Aensuring anaerobic conditions in the culture vessel
Bpurification of product
Caddition of preservatives to the product
Dailability of oxygen throughout the process

Which of the following rRNAs acts as structural RNA as well as ribozyme in bacterial
A5·8s rRNA
B5S rRNA
C18 S rRNA
D23S rRNA

A true breeding plant is
AAlways homozygous recessive in its genetic constitution
BOne that is able to bred on its own
CProduced due to cross pollination among unrelated plants
Dnear homozygous and produces offsspiring of its kind

The equivalent of a structural gene is A true breeding plant is
Arecon
Bmuton
Ccistron

Doperon

The mechanism that causes a gene to move from one linkage group to another is called
ACorossing-over
Binversion
Cduplication
Dtranslocation

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