GSEB 2021 Biology Question Paper with Answer and Solution

34 QuestionsEnglishWith Solutions

BiologyQ134 of 34 questions

Page 1 of 1 · English

1
BiologyEasyMCQGSEB · 2021
What specialized photosynthetic pathway do some desert plants have?
A
$CAM$ pathway
B
$C_4$ pathway
C
$C_3$ pathway
D
$C_3$ and $C_4$ pathway

Solution

(A) The correct answer is $A$.
Desert plants,such as succulents,utilize the Crassulacean Acid Metabolism $(CAM)$ pathway.
This specialized photosynthetic pathway allows these plants to open their stomata at night to take in $CO_2$ and store it as organic acids,which helps in minimizing water loss through transpiration during the hot,dry day.
2
BiologyEasyMCQGSEB · 2021
The medicinal plant $Rauwolfia$ $vomitoria$ produces which chemical?
A
Dopamine
B
Ethylene
C
Serotonin
D
Reserpine

Solution

(D) The medicinal plant $Rauwolfia$ $vomitoria$ is well-known for producing a potent chemical substance called $Reserpine$.
$Reserpine$ is an alkaloid that has been used medicinally to treat high blood pressure and certain mental disorders.
This plant is a classic example of chemical diversity in nature, which is a significant aspect of biodiversity.
3
BiologyEasyMCQGSEB · 2021
Amazon forest is estimated to produce . . . . . . % of total oxygen in earth's atmosphere through photosynthesis.
A
$20$
B
$40$
C
$25$
D
$10$

Solution

(A) The Amazon rainforest is often referred to as the 'lungs of the planet'. It is estimated that the Amazon forest contributes approximately $20\%$ of the total oxygen in the earth's atmosphere through the process of photosynthesis. Therefore,the correct option is $A$.
4
BiologyEasyMCQGSEB · 2021
Which catfish has become a threat to the indigenous catfish in our rivers?
A
European catfish
B
African catfish
C
Asian catfish
D
American catfish

Solution

(B) The $Clarias$ $gariepinus$ (African catfish) was introduced illegally for aquaculture purposes in India. This species has become a major threat to the indigenous catfish species in our rivers because it is highly invasive, aggressive, and competes for food and habitat, leading to the decline of native populations.
5
BiologyEasyMCQGSEB · 2021
$ELISA$ method works on which of the following principles?
A
Gel electrophoresis
B
Antigen-antibody interaction
C
$R$-$DNA$ technology
D
$PCR$

Solution

(B) The $ELISA$ $(Enzyme-Linked Immunosorbent Assay)$ method is a diagnostic technique used to detect the presence of specific antigens or antibodies in a sample.
It is based on the principle of $Antigen-Antibody$ interaction,where an enzyme-linked antibody binds to a specific antigen,and the subsequent enzymatic reaction produces a detectable signal (usually a color change).
Therefore,the correct principle is $Antigen-Antibody$ interaction.
6
BiologyEasyMCQGSEB · 2021
Which peptide is not present in mature insulin?
A
$A$-peptide
B
$B$-peptide
C
$C$-peptide
D
Glycosidic bond

Solution

(C) In mammals,including humans,insulin is synthesized as a pro-hormone called pro-insulin.
Pro-insulin consists of three polypeptide chains: $A$,$B$,and $C$.
The $C$-peptide is an extra stretch of amino acids that is removed during the maturation process of pro-insulin into mature insulin.
Therefore,mature insulin consists only of $A$ and $B$ polypeptide chains linked by disulfide bridges,and the $C$-peptide is absent.
7
BiologyEasyMCQGSEB · 2021
Which process is useful in pest resistance plant?
A
Protein Interference
B
$DNA$ Interference
C
Enzyme Interference
D
$RNA$ Interference

Solution

(D) $RNA$ Interference $(RNAi)$ is a biological process in which $RNA$ molecules inhibit gene expression or translation,by neutralizing targeted $mRNA$ molecules. This method is used in biotechnology to develop pest-resistant plants,such as tobacco plants resistant to the nematode $Meloidegyne$ $incognitia$. By introducing $RNAi$ constructs,the plant produces double-stranded $RNA$ that silences specific genes essential for the pest's survival,thereby protecting the plant.
8
BiologyEasyMCQGSEB · 2021
From where is agarose gel derived?
A
Fungi
B
Bryophytes
C
Bacteria
D
Sea weed

Solution

(D) Agarose is a natural polymer extracted from sea weeds (marine red algae such as $Gelidium$ and $Gracilaria$). It is a polysaccharide used in gel electrophoresis to separate $DNA$ fragments based on their size.
9
BiologyEasyMCQGSEB · 2021
By which process is a fragment of $DNA$ transferred into a bacterial host cell?
A
Translation
B
Transformation
C
Transcription
D
Transportation

Solution

(B) The correct answer is $B$. Transformation is the process by which a bacterial cell takes up foreign genetic material $(DNA)$ from its surroundings. In biotechnology,this is a fundamental technique used to introduce recombinant $DNA$ into host cells like $E. coli$ to produce desired proteins or clones.
10
BiologyEasyMCQGSEB · 2021
Which was the first restriction endonuclease isolated and identified?
A
Hind $II$
B
Ligase
C
Palindrome
D
Hind $I$

Solution

(A) The first restriction endonuclease to be isolated and identified was $Hind \ II$. It was discovered by Hamilton Smith and his colleagues in $1970$. It was found to always cut $DNA$ molecules at a particular point by recognizing a specific sequence of $6$ base pairs.
11
BiologyEasyMCQGSEB · 2021
. . . . . . fish eat mosquito eggs.
A
Perambia
B
Gambusia
C
Tiger fish
D
Silfer fish

Solution

(B) $Gambusia$ fish are known as larvivorous fish. They are introduced into water bodies to control the population of mosquitoes because they feed on mosquito larvae and eggs,thereby helping to prevent diseases like malaria and dengue.
12
BiologyEasyMCQGSEB · 2021
The use of . . . . . . is very effective as an emergency contraceptive.
A
Volts
B
Natural methods
C
Prevention
D
Progesterone-estrogen combinations

Solution

(D) The use of $Progesterone-estrogen$ combinations or their administration with $IUDs$ within $72$ hours of coitus has been found to be very effective as emergency contraceptives. These are used to avoid possible pregnancy due to rape or casual unprotected intercourse.
13
BiologyEasyMCQGSEB · 2021
After getting into the body of the person,$HIV$ enters into . . . . . . .
A
Neurons
B
Epithelial cells
C
Muscle cells
D
Macrophages

Solution

(D) After entering the human body,the $HIV$ virus first infects macrophages. These macrophages act as a factory for the virus,producing more viral particles. Subsequently,the virus spreads to helper $T$-lymphocytes ($T_H$ cells) in the blood,where it continues to replicate and cause a progressive decrease in the number of helper $T$-lymphocytes,leading to the weakening of the immune system. Therefore,the correct option is $D$.
14
BiologyEasyMCQGSEB · 2021
Which of the following is an example of an auto-immune disease?
A
Rheumatoid Arthritis
B
Malaria
C
Cancer
D
$AIDS$

Solution

(A) An auto-immune disease occurs when the immune system mistakenly attacks the body's own healthy cells and tissues.
Rheumatoid Arthritis is a classic example of an auto-immune disease where the immune system attacks the joints,causing inflammation and pain.
Malaria is an infectious disease caused by protozoa.
Cancer is a disease characterized by uncontrolled cell division.
$AIDS$ is an immunodeficiency disease caused by the $HIV$ virus.
15
BiologyEasyMCQGSEB · 2021
Pneumonia and common cold are . . . . . . diseases.
A
Insect induced
B
Food induced
C
Air induced
D
Water induced

Solution

(C) Pneumonia is caused by bacteria like $Streptococcus \text{ } pneumoniae$ and $Haemophilus \text{ } influenzae$, while the common cold is caused by rhinoviruses.
Both of these diseases are primarily transmitted through droplets released by an infected person during coughing or sneezing, or by sharing contaminated objects.
Since these pathogens are spread through the air, these are classified as air-borne or air-induced diseases.
Therefore, the correct option is $C$.
16
BiologyEasyMCQGSEB · 2021
$ . . . . . . $ hormone is associated with parturition.
A
$FSH$
B
$hCG$
C
$Oxytocin$
D
$LTH$

Solution

(C) The correct answer is $Oxytocin$.
$Oxytocin$ is a hormone released by the posterior pituitary gland that plays a critical role in parturition (childbirth).
It acts on the uterine muscles and causes stronger uterine contractions,which helps in the expulsion of the fetus from the uterus.
17
BiologyEasyMCQGSEB · 2021
After spermiogenesis,sperm head is embedded in . . . . . . .
A
Sertoli cells
B
Interstitial cells
C
Leydig cells
D
Corpus luteum

Solution

(A) After the process of spermiogenesis,the transformation of spermatids into spermatozoa occurs.
Following this,the sperm heads become embedded in the $Sertoli$ cells to receive nourishment.
Finally,they are released from the seminiferous tubules by the process called spermiation.
18
BiologyEasyMCQGSEB · 2021
The puffed-up appearance of dough is due to the production of . . . . . . gas.
A
Nitrogen
B
Oxygen
C
Carbon dioxide
D
Hydrogen

Solution

(C) The puffed-up appearance of dough used for making foods such as dosa and idli is due to the production of $CO_2$ gas.
This process occurs during fermentation,where microorganisms like bacteria (e.g.,Leuconostoc and Streptococcus species) break down carbohydrates present in the dough.
As a byproduct of this anaerobic respiration,$CO_2$ is released,which gets trapped in the dough,causing it to rise and appear puffed up.
19
BiologyEasyMCQGSEB · 2021
Traditional drinks like toddy are obtained from which plant?
A
Palm
B
Dates
C
Coconut
D
Mango

Solution

(A) The traditional drink known as 'toddy' is a fermented beverage produced from the sap of various species of palm trees,such as the Palmyra palm ($Borassus$ $flabellifer$). The sap is collected by tapping the inflorescence of the palm,which then undergoes natural fermentation by yeasts and bacteria present in the environment to produce the alcoholic drink.
20
BiologyEasyMCQGSEB · 2021
Which microbes are responsible for making curd from milk?
A
Propionibacterium sharmanii
B
Lactic acid bacteria
C
Saccharomyces cerevisiae
D
Staphylococcus bacteria

Solution

(B) Lactic acid bacteria $(LAB)$,such as $Lactobacillus$,are responsible for converting milk into curd. These bacteria grow in milk and produce acids that coagulate and partially digest the milk proteins,thereby converting it into curd.
21
BiologyEasyMCQGSEB · 2021
Which insect helps to get rid of aphids?
A
Dragonflies
B
Fly
C
Ladybird
D
Cockroaches

Solution

(C) The correct answer is $C$. Ladybirds (beetles with red and black markings) are well-known biological control agents that feed on aphids. They are used in agriculture to naturally control aphid populations,which are pests that damage crops by sucking plant sap.
22
BiologyEasyMCQGSEB · 2021
Which bacteria are responsible for biogas production?
A
Acetobacter
B
Rhizobium
C
Lactobacillus
D
Methanobacterium

Solution

(D) The correct answer is $D$. Methanogens,such as $Methanobacterium$,are anaerobic bacteria that grow in anaerobic conditions on cellulosic material. They produce large amounts of methane along with $CO_2$ and $H_2$,which is collectively known as biogas.
23
BiologyEasyMCQGSEB · 2021
Which of the following is used as a clot buster from patient blood vessels?
A
Streptokinase
B
Pectinase
C
Proteases
D
Nucleases

Solution

(A) Streptokinase,produced by the bacterium $Streptococcus$ and modified by genetic engineering,is used as a 'clot buster' for removing clots from the blood vessels of patients who have undergone myocardial infarction (heart attack).
$1$. $Streptokinase$: Acts as a clot buster.
$2$. $Pectinase$: Used for clearing fruit juices.
$3$. $Proteases$: Used in detergent formulations.
$4$. $Nucleases$: Enzymes that cleave the phosphodiester bonds between nucleotide subunits of nucleic acids.
Therefore,the correct option is $A$.
24
BiologyEasyMCQGSEB · 2021
The coding sequences of genes are known as . . . . . . .
A
Regulator
B
Introns
C
Promotor
D
Exons

Solution

(D) In eukaryotic genes,the coding sequences that appear in mature $mRNA$ are called $Exons$.
$Introns$ are the intervening,non-coding sequences that are removed during the process of $RNA$ splicing.
$Promoters$ and $Regulators$ are sequences involved in the control of gene expression,not the coding sequences themselves.
Therefore,the correct answer is $D$.
25
BiologyEasyMCQGSEB · 2021
In the haploid content of human $DNA$,how many base pairs are observed?
A
$3.3 \times 10^9 \text{ bp}$
B
$4.6 \times 10^6 \text{ bp}$
C
$6.6 \times 10^9 \text{ bp}$
D
$9.6 \times 10^6 \text{ bp}$

Solution

(A) The human genome consists of approximately $3.3 \times 10^9$ base pairs in its haploid content.
This value represents the total number of nucleotide base pairs present in a single set of human chromosomes $(n)$.
In contrast,the diploid content $(2n)$ of human $DNA$ is approximately $6.6 \times 10^9$ base pairs.
26
BiologyEasyMCQGSEB · 2021
The unequivocal proof that $DNA$ is the genetic material was given by whom?
A
Mathew Meselson and Franklin Stahl
B
Watson and Crick
C
Colin Macleod and Maclyn-McCarty
D
Alfred Hershey and Martha Chase

Solution

(D) The unequivocal proof that $DNA$ is the genetic material came from the experiments of Alfred Hershey and Martha Chase in $1952$.
They worked with bacteriophages,which are viruses that infect bacteria.
By using radioactive isotopes ($^{32}P$ to label $DNA$ and $^{35}S$ to label proteins),they demonstrated that only the $DNA$ entered the bacterial cell,while the protein coat remained outside.
This confirmed that $DNA$ is the hereditary material that carries genetic information.
27
BiologyEasyMCQGSEB · 2021
$5$-Methyl uracil is . . . . . . .
A
Thymine
B
Cytosine
C
Adenine
D
Uracil

Solution

(A) The chemical name for $5$-Methyl uracil is Thymine.
Thymine is a pyrimidine nitrogenous base found in $DNA$.
It is structurally similar to Uracil,which is found in $RNA$,but with a methyl group $(-CH_3)$ attached at the $5^{th}$ position of the pyrimidine ring.
Therefore,the correct option is $A$.
28
BiologyEasyMCQGSEB · 2021
Brood parasitism is found in what?
A
Amphibians
B
Reptiles
C
Aves
D
Fish

Solution

(C) Brood parasitism is a phenomenon in which a parasitic bird lays its eggs in the nest of a host bird and lets the host incubate them. This is a classic example of parasitism observed in birds $(Aves)$. $A$ well-known example is the cuckoo ($Cuculus$ $canorus$) laying its eggs in the nest of a crow.
29
BiologyEasyMCQGSEB · 2021
The Mendel dihybrid phenotypic ratio is . . . . . . .
A
$1$ : $3$ : $3$ : $9$
B
$3$ : $9$ : $1$ : $3$
C
$9$ : $3$ : $3$ : $1$
D
$6$ : $3$ : $3$ : $4$

Solution

(C) In a dihybrid cross,Mendel studied the inheritance of two pairs of contrasting traits simultaneously. For example,when crossing a plant with round and yellow seeds $(RRYY)$ with a plant having wrinkled and green seeds $(rryy)$,the $F_1$ generation produces all round and yellow seeds $(RrYy)$. Upon self-pollination of the $F_1$ generation,the $F_2$ generation exhibits four different phenotypes in the ratio of $9 : 3 : 3 : 1$. These represent:
$1$. Round-Yellow $(9)$
$2$. Round-Green $(3)$
$3$. Wrinkled-Yellow $(3)$
$4$. Wrinkled-Green $(1)$
30
BiologyEasyMCQGSEB · 2021
What do the genes responsible for skin color indicate?
A
Pleiotropy
B
Linkage
C
Polygenic inheritance
D
Co-dominance

Solution

(C) Skin color in humans is a classic example of polygenic inheritance. In this type of inheritance,a single phenotypic trait is controlled by two or more genes,and each allele has a cumulative or additive effect on the phenotype. This results in a continuous range of skin tones rather than distinct categories.
31
BiologyEasyMCQGSEB · 2021
The principle that alleles live together without showing any blending is known as . . . . . . .
A
Co-dominance
B
Law of Segregation
C
Law of Dominance
D
Chromosomal Theory

Solution

(B) The $Law$ $of$ $Segregation$ (also known as the $Law$ $of$ $Purity$ $of$ $Gametes$) states that although the two alleles of a gene pair live together in an individual, they do not blend or mix with each other. During the formation of gametes, these alleles separate (segregate) so that each gamete receives only one of the two alleles. This ensures that the traits remain distinct and pure in subsequent generations.
32
BiologyEasyMCQGSEB · 2021
In . . . . . . pollen grains cause allergy.
A
Water hyacinth
B
Common pansy
C
Oxalis
D
Parthenium (Carrot grass)

Solution

(D) $Parthenium$,also known as carrot grass,is an invasive weed that was introduced into India as a contaminant with imported wheat. Its pollen grains are a major cause of respiratory allergies and hay fever in humans.
33
BiologyEasyMCQGSEB · 2021
In . . . . . . ,pollen grains are long and ribbon-like.
A
Sea grasses
B
Vallisneria
C
Commelina
D
Hibiscus

Solution

(A) The correct answer is $A$. In many aquatic plants,such as sea grasses (e.g.,$Zostera$),the pollen grains are long and ribbon-like. This specific shape helps them to be carried passively by water currents to reach the stigma of the female flower.
34
BiologyEasyMCQGSEB · 2021
In plants,the ovule is transformed into which of the following structures after fertilization?
A
Endosperm
B
Seed
C
Embryo
D
Fruit

Solution

(B) After fertilization in angiosperms,the ovule undergoes significant developmental changes. The integuments of the ovule harden to form the seed coat,and the entire ovule matures into a seed. Meanwhile,the ovary develops into the fruit.

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