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Biology: CUET Mock Test - 10 - Class 12 MCQ


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30 Questions MCQ Test - Biology: CUET Mock Test - 10

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Biology: CUET Mock Test - 10 - Question 1

According to the law of dominance, what are the discrete units that control the characters?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 1

The law of dominance states characters encoded by discrete units. Mendel called these factors, which he believed transferred from parents during progeny during fertilization. These are now known as genes.

Biology: CUET Mock Test - 10 - Question 2

What does the given diagram show?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 2

The given diagram shows the process of transcription in Eukaryotes. This process is characterized by several steps including initiation, elongation, and termination, followed by post-transcriptional modifications such as splicing, capping, and polyadenylation.

Key Points

  • Transcription in Eukaryotes is complex and involves the modification of the pre-mRNA transcript including splicing out introns, adding a 5' cap, and a poly-A tail at the 3' end.
  • The process ensures that the mRNA is mature and ready to be exported from the nucleus for translation.

Additional Information

  • Post-transcriptional processing of RNA in Prokaryotes (Option 1) is incorrect because prokaryotes generally do not undergo extensive post-transcriptional modifications like eukaryotes do.
  • Termination of translation (Option 2) refers to the process that occurs at the end of protein synthesis in the ribosome, not related to RNA processing.
  • The process of transcription in Prokaryotes (Option 3) is simpler and does not involve the same level of RNA processing as seen in eukaryotes.
Biology: CUET Mock Test - 10 - Question 3

Match List - I with List - II.

Choose the correct answer from the options given below:

Detailed Solution for Biology: CUET Mock Test - 10 - Question 3

The correct option is 'A - III, B - II, C - IV, D - I​'.

Key Points

  • Methyl Guanosine Triphosphate (mGTP) is related to the cap structure of mRNA.
    • The cap structure, found at the 5' end of mRNA, is crucial for mRNA stability and the initiation of translation. It is formed by the addition of a methylated guanosine triphosphate (mGTP).
    • This modification is known as the 5' cap and is denoted as (A) - III in the matching, representing its role in mRNA processing and function.
  • Introns are non-coding sequences within a gene.
    • Introns are sequences within a gene that are transcribed into RNA but are removed during RNA splicing before translation into protein. Thus, they do not encode part of the protein.
    • This process is a key aspect of gene expression in eukaryotes, making (B) - II the correct match.
  • The Poly A tail is added to mRNA at the 3' end.
    • The Poly A tail is a stretch of adenine nucleotides added to the 3' end of pre-mRNA molecules. This modification is crucial for mRNA stability and the regulation of translation.
    • Therefore, (C) - IV correctly matches the Poly A tail with its role in mRNA maturation.
  • Fully processed hnRNA (heterogeneous nuclear RNA) is essentially mature mRNA.
    • hnRNA refers to the initial RNA transcript that includes both introns and exons. After processing, which includes splicing out introns, adding a 5' cap, and a 3' Poly A tail, it becomes mature mRNA ready for translation.
    • Thus, (D) - I is the correct match, indicating the final processed form of hnRNA, ready for protein synthesis.

Therefore the correct pairing is:
A - III: Methyl Guanosine Triphosphate - mRNA cap structure
B - II: Intron - Non-coding sequence within a gene
C - IV: Poly A tail - Added to mRNA at the 3' end
D - I: Fully processed hnRNA - Mature mRNA

Biology: CUET Mock Test - 10 - Question 4

RNA polymerase III is responsible for the transcription of which of the following?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 4

Key Points

  • RNA polymerase III is responsible for the transcription of tRNA, 5srRNA, and snRNA.
  • This enzyme plays a crucial role in the synthesis of transfer RNAs (tRNAs), small nuclear RNAs (snRNAs), and the 5S ribosomal RNA (5srRNA).

Additional Information

  • Option 1 (tRNA, rRNA, mRNA) is incorrect because RNA polymerase III does not transcribe mRNA. That task is primarily associated with RNA polymerase II.
  • Option 3 (5srRNA, tRNA, mRNA) is incorrect as it mistakenly includes mRNA, which is not synthesized by RNA polymerase III.
  • Option 4 (snRNA, rRNA, 5srRNA) is partially incorrect because although RNA polymerase III transcribes snRNA and 5srRNA, it does not transcribe the majority of rRNA. The transcription of rRNA is mainly the function of RNA polymerase I.
  • It's important to note that the specific roles of RNA polymerases can slightly vary across different organisms, but the general functions described here are consistent for eukaryotic cells
Biology: CUET Mock Test - 10 - Question 5

Identify the correct sequence of events occurring in the process shown in the figure.
(A) Tailing and Splicing
(B) Transport of the molecule out of the nucleus
(C) Transcription of precursor RNA by RNA polymerase II
(D) Capping

Choose the correct answer from the options given below:

Detailed Solution for Biology: CUET Mock Test - 10 - Question 5

Key Points

  • The correct sequence of events in the process of RNA maturation and transport is: Transcription of precursor RNA by RNA polymerase II (C), Capping (D), Tailing and Splicing (A), Transport of the molecule out of the nucleus (B).
  • This sequence reflects the correct chronological order of RNA processing and transport in eukaryotic cells.

Additional Information

  • Option 1 and Option 2 are incorrect because they suggest that the transport of the molecule out of the nucleus occurs before the critical steps of capping, tailing, and splicing, which is not accurate. These modifications need to occur before RNA can be transported out of the nucleus.
  • Option 4 incorrectly places tailing and splicing before capping, which is not the correct order of events. Capping occurs immediately after the initiation of transcription and is followed by tailing and splicing.
  • The process of transcription (C) by RNA polymerase II produces a precursor RNA molecule, which then undergoes capping (D) at its 5' end, a modification essential for mRNA stability and initiation of translation.
  • After capping, the precursor RNA undergoes tailing and splicing (A), where a poly(A) tail is added to the 3' end, and non-coding sequences (introns) are removed, respectively.
  • Finally, the mature RNA molecule is transported out of the nucleus (B) to the cytoplasm where it can be translated into a protein.
Biology: CUET Mock Test - 10 - Question 6

Transcription can be coupled with translation in bacteria because:

Detailed Solution for Biology: CUET Mock Test - 10 - Question 6

Key Points

  • In bacteria, transcription and translation can occur simultaneously because there is no physical barrier separating the cytosol and nucleus, as bacteria lack a nucleus.
  • This allows the newly synthesized mRNA to be immediately available for translation into proteins, facilitating a rapid response to environmental changes.

Additional Information

  • Option 2: While it's true that post-transcriptional processing in bacteria is simpler than in eukaryotes, this is not the reason why transcription can be coupled with translation. The key factor is the lack of a nuclear membrane.
  • Option 3: The statement is incorrect as it mistakenly claims transcription is faster than itself. Even if it meant to compare transcription and translation speeds, this is not the reason for their coupling in bacteria.
  • Option 4: The complexity of the RNA molecule does not influence the coupling of transcription and translation. This option is irrelevant to the concept of spatial and temporal coupling of these processes in bacteria.
Biology: CUET Mock Test - 10 - Question 7

Vectors from which of the following species were used here?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 7

Concept:

  • Plasmid vector: Plasmid are extrachromosomal DNA, circular DNA molecule. It is widely used as a tool for cloning in genetic engineering.
  • T-DNA: The transfer DNA or T-DNA is the transferred DNA of the tumor-inducing (Ti) plasmid of species such as Agrobacterium tumefaciens
  • To prevent the infection of the roots by the nematode Meloidegyne incognita a strategy was developed which was based on the process of RNA interference (RNAi).
  • In all eukaryotic organisms RNAi takes place as a method of cellular defense.
  • This process is based on suppression of gene expression by complementary dsRNA molecule. It silences specific mRNA that binds to and prevents translation of the mRNA (silencing).
  • The complementary RNA source could be from an infection by viruses having RNA genomes or mobile genetic elements (transposons) that replicate via an RNA intermediate.
  • Nematode-specific genes were introduced into the host plant using Agrobacterium vectors.
  • It produced both sense and anti-sense RNA in the host cells after the introduction of DNA in the vector .
  • The sense and anti-sense RNA are complementary to each other that forms a double stranded RNA(dsRNA). It initiates RNAi and helps in silencing the specific mRNA of the nematode.
  • As a result, the parasite could not survive in a transgenic host expressing specific interfering RNA.
  • Thus, the transgenic plant protected itself from the parasite.

Explanation:

Statement 1) Agrobacterium tumifaciens -CORRECT

  • Vectors from Agrobacterium tumifaciens were used.
  • This option is correct.

Statement 2) Bacillus thuringiensis -INCORRECT

  • Bacillus thuringiensis is used for Bt cotton
  • This option is incorrect.

Statement 3) Thermus aquaticus -INCORRECT

  • Thermus aquaticus is a bacterium that is able to tolerate high temperature and vectors from this specie was not used.
  • This option is incorrect.

Statement 4) Meloidegyne incognita-INCORRECT

  • The nematode Meloidegyne incognita is the parasite that infects the roots.
  • This option is incorrect

So, the correct statement is Statement 1) Agrobacterium tumifaciens

Biology: CUET Mock Test - 10 - Question 8

Choose the INCORRECT statement regarding the technique involved in producing the above transgenic plant:

Detailed Solution for Biology: CUET Mock Test - 10 - Question 8

Concept:

  • To prevent the infection of the roots by the nematode Meloidegyne incognita a strategy was developed which was based on the process of RNA interference (RNAi).
  • In all eukaryotic organisms, RNAi takes place as a method of cellular defense.
  • This process is based on the suppression of gene expression by complementary dsRNA molecules. It silences specific mRNA that binds to and prevents translation of the mRNA (silencing).
  • The complementary RNA source could be from infection by viruses having RNA genomes or mobile genetic elements (transposons) that replicate via an RNA intermediate.
  • Nematode-specific genes were introduced into the host plant using Agrobacterium vectors,
  • It produced both sense and anti-sense RNA in the host cells after the introduction of DNA in the vector.
  • The sense and anti-sense RNA are complementary to each other and form a double-stranded RNA(dsRNA). It initiates RNAi and helps in silencing the specific mRNA of the nematode.
  • As a result, the parasite could not survive in a transgenic host expressing specific interfering RNA.
  • Thus, the transgenic plant protected itself from the parasite.

Explanation:

Statement 1) It was based on RNA interference -CORRECT

  • The process was based on RNA interference that helps in gene suppression
  • So, this option is correct.

Statement 2) It involves silencing of host mRNA INCORRECT

  • It involves silencing the parasite or nematode mRNA.
  • So, this option is incorrect.

Statement 3) A complementary ds-RNA binds and prevents translation of mRNA -CORRECT

  • This process is based on the suppression of gene expression by complementary dsRNA molecules.
  • It silences specific mRNA that binds to and prevents translation of the mRNA (silencing).
  • So, this option is correct.

Statement 4) Both sense and anti-sense RNA are required in this process-CORRECT

  • The sense and anti-sense RNA are complementary to each other and form a double-stranded RNA(dsRNA).
  • It initiates RNAi and helps in silencing the specific mRNA of the nematode.
  • So, this option is correct.

So, the incorrect statement is Statement 2) It involves silencing of host mRNA

Biology: CUET Mock Test - 10 - Question 9

The plasmid containing T-DNA is known as:

Detailed Solution for Biology: CUET Mock Test - 10 - Question 9

Concept:

  • GMO: GMO or genetically modified organism is a plant or animal that has been genetically modified through the insertion of genes from other organisms through molecular biology techniques. Genetic modification is a useful tool as it helps in the development of crops that can tolerate abiotic stress, are insect resistant and pest-resistant, has high nutritional value, etc.
  • Transgenic plants: Plants whose DNA is modified using genetic engineering techniques are known as transgenic plants. They are also known as genetically modified organisms.
  • Plasmid vector: Plasmids are extrachromosomal DNA, circular DNA molecules. It is widely used as a tool for cloning in genetic engineering.
  • T-DNA: The transfer DNA or T-DNA is the transferred DNA of the tumor-inducing (Ti) plasmid of species such as Agrobacterium tumefaciens

Explanation:

Statement 1) pBR322 -INCORRECT

  • pBR322 is a plasmid cloning vector in E.coli used for cloning and recombinant DNA technology purpose.
  • This option is incorrect

Statement 2) BAC-INCORRECT

  • A bacterial artificial chromosome (BAC) is an engineered DNA molecule used to clone DNA sequences in bacterial cells (for example, E. coli).
  • This option is incorrect

Statement 3) Ti-plasmid -CORRECT

  • Ti-plasmid or tumor-inducing plasmid is a plasmid found in pathogenic species of Agrobacterium species.
  • The plasmid containing T-DNA or transfer DNA is Ti plasmid.
  • So, this option is correct.

Statement 4) YAC -INCORRECT

  • The yeast artificial chromosome is a cloning vector used for yeast cells.
  • This option is incorrect

So, the incorrect statement is Statement 3) Ti-plasmid

Biology: CUET Mock Test - 10 - Question 10

Identify the plant 'A' in the given case:

Detailed Solution for Biology: CUET Mock Test - 10 - Question 10

Concept:

  • Plasmid vector: Plasmids are extrachromosomal DNA, circular DNA molecules. It is widely used as a tool for cloning in genetic engineering.
  • T-DNA: The transfer DNA or T-DNA is the transferred DNA of the tumor-inducing (Ti) plasmid of species such as Agrobacterium tumefaciens
  • To prevent the infection of the roots of plant tobacco by the nematode Meloidegyne incognita a strategy was developed which was based on the process of RNA interference (RNAi).
  • In all eukaryotic organisms, RNAi takes place as a method of cellular defense.
  • This process is based on the suppression of gene expression by complementary dsRNA molecules. It silences specific mRNA that binds to and prevents translation of the mRNA (silencing).
  • The complementary RNA source could be from infection by viruses having RNA genomes or mobile genetic elements (transposons) that replicate via an RNA intermediate.
  • Nematode-specific genes were introduced into the host plant using Agrobacterium vectors.
  • It produced both sense and anti-sense RNA in the host cells after the introduction of DNA in the vector.
  • The sense and anti-sense RNA are complementary to each other and form a double-stranded RNA(dsRNA). It initiates RNAi and helps in silencing the specific mRNA of the nematode.
  • As a result, the parasite could not survive in a transgenic host expressing specific interfering RNA.
  • Thus, the transgenic plant protected itself from the parasite.

Explanation:

Statement 1) Cotton -INCORRECT

  • This option is incorrect

Statement 2) Tobacco CORRECT

  • The nematode Meloidegyne incognita infects the roots of plant tobacco and reduces its yield
  • This option is correct

Statement 3) Corn -INCORRECT

  • This option is incorrect

Statement 4) Tomato -INCORRECT

  • This option is incorrect

So, the correct statement is Statement 2) Tobacco

Biology: CUET Mock Test - 10 - Question 11

Transgenic plants can also be produced by other methods and for other purposes. Which of the following is a correct example?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 11

Concept:

  • GMO: GMO or genetically modified organism is a plant or animal that has been genetically modified through the insertion of genes from other organisms through molecular biology techniques. Genetic modification is a useful tool as it helps in the development of crops that can tolerate abiotic stress, are insect-resistant and pest-resistant, has high nutritional value etc.
  • Transgenic plants: Plants whose DNA is modified using genetic engineering techniques are known as transgenic plants. They are also known as genetically modified organisms.
  • Plasmid vector: Plasmids are extrachromosomal DNA, circular DNA molecules. It is widely used as a tool as a vector for cloning in genetic engineering.
  • T-DNA: The transfer DNA or T-DNA is the transferred DNA of the tumor-inducing (Ti) plasmid of species such as Agrobacterium tumefaciens

Explanation:

Statement 1) Golden rice - Disease resistance - INCORRECT

  • Golden rice is produced by genetic engineering and is a variety of rice (Oryza sativa).
  • It is produced to enrich the nutritional value by biosynthesizing beta-carotene, a precursor of vitamin A, in the edible parts of the rice.
  • It is generally produced to meet the needs of areas with a shortage of dietary vitamin A.
  • This option is incorrect.

Statement 2) Bt-corn - High nutritional value - INCORRECT

  • Bt-corn is a type of genetically modified organism which is created as an insect resistance crop.
  • This option is incorrect

Statement 3) Bt-cotton - Insect resistance – correct

  • Bt cotton is a genetically engineered plant by insertion of one or more genes from a common soil bacterium, Bacillus thuringiensis.
  • Bacillus thuringiensis produces proteins that act as insecticides.
  • So, this is the correct option

Statement 4) Both 1 and 2

  • This option is incorrect

So, the correct statement is Statement 3) Bt-cotton - Insect resistance

Biology: CUET Mock Test - 10 - Question 12

Which of the following is not a statement of the principle of dominance?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 12

The principle of dominance does not state the segregation of factors. This is stated by the law of segregation or separation.

Biology: CUET Mock Test - 10 - Question 13

A homozygous parent produces gametes that are ______; while the heterozygous parent produces gametes that are _______

Detailed Solution for Biology: CUET Mock Test - 10 - Question 13

The law of segregation states that the factors separate during gamete formation. Thus a homozygous parent will produce gametes that have similar factors while the heterozygous parent would produce gametes with dissimilar alleles.

Biology: CUET Mock Test - 10 - Question 14

What generation of Mendelian cross has a phenotypic ratio of 3:1?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 14

The phenotypic ratio is the ratio of different phenotypes observed in the progeny. In the F2 generation of a Mendelian cross, there are 75% plants with dominant phenotype and 25% plants with a recessive phenotype. This gives a phenotypic ratio of 3:1.

Biology: CUET Mock Test - 10 - Question 15

The ratio of genotypes observed in progeny after a cross has been performed is called ________

Detailed Solution for Biology: CUET Mock Test - 10 - Question 15

The genotypes of a progeny can be studied using Punnett square. The ratio of different genotypes is called the genotypic ratio.

Biology: CUET Mock Test - 10 - Question 16

What is represented in the boxes of the Punnett square?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 16

In the Punnett square, the boxes are filled with the offsprings that can be produced, in principle, from the combinations of gametes of both parents. This can be used to determine the genotypic and phenotypic ratios of the progeny.

Biology: CUET Mock Test - 10 - Question 17

Who deserves the credit to discover Punnett square?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 17

The Punnett square was discovered by a British scientist named Reginald Punnett. Its importance was recognized by Gregor Mendel, who used it to study the patterns of inheritance and thus formulate the laws of inheritance.

Biology: CUET Mock Test - 10 - Question 18

What is the process of removal of anthers termed?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 18

Emasculation is the process of removal of anthers. This is carried out to carry out pollination in a controlled manner and avoid self-pollination.

Biology: CUET Mock Test - 10 - Question 19

What is the generation of plants produced by the crossing of true-breeding plants called?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 19

True-breeding plants are taken as parental plants in crosses. Hence offsprings produced by the crossing of these true-breeding plants are F1 progeny.

Biology: CUET Mock Test - 10 - Question 20

What should be the phenotype of the F1 progeny produced by a cross between tall and dwarf true-breeding garden pea plants?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 20

Tall plants are dominant over dwarf plants. Being true-breeding parents, the offsprings will all be heterozygous. Moreover, hence phenotypically, all of them will be tall.

Biology: CUET Mock Test - 10 - Question 21

What should be the phenotype of a cross between violet and white-flowered true-breeding garden pea plants?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 21

Violet is the dominant factor over white in pea flowers. Hence violet can express even in the presence of white. The cross of violet true-breeding and white true-breeding pea plants will produce all heterozygous offsprings. Thus, all of them will have violet flowers.

Biology: CUET Mock Test - 10 - Question 22

The factor which expresses in homozygous and heterozygous states is called _______

Detailed Solution for Biology: CUET Mock Test - 10 - Question 22

A dominant factor masks the expression of its recessive counterpart. Thus, it can express in both homozygous and heterozygous states.

Biology: CUET Mock Test - 10 - Question 23

During meiosis, what happens to the parental alleles?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 23

Based on his studies on pea plants, he observed that the parental recessive traits were observed again only in the F2 progeny without any form of blending in F1 generation. This points out that the factors segregate or separate during the process of meiosis.

Biology: CUET Mock Test - 10 - Question 24

The presence of two different alleles at a particular locus results in _________

Detailed Solution for Biology: CUET Mock Test - 10 - Question 24

The presence of two different alleles at a particular locus results in _________
a) Homozygosity
b) Heterozygosity
c) Hemizygosity
d) Nullizygosity

Biology: CUET Mock Test - 10 - Question 25

A plant that exhibits two alleles for only one trait is called ________

Detailed Solution for Biology: CUET Mock Test - 10 - Question 25

Monohybrid refers to a hybrid that differs at only one gene. Thus, a plant that exhibits two alleles for one trait is a monohybrid.

Biology: CUET Mock Test - 10 - Question 26

 If VV produces violet flowers and vv produces white flowers, what will be the phenotype and genotype of the F1 progeny?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 26

The VV and vv upon crossing will produce all progeny with genotype Vv. This is the heterozygous state. Violet being dominant over white, all the progeny will have violet flowers.

Biology: CUET Mock Test - 10 - Question 27

With green pods as a dominant trait over yellow, which of the following crosses will result in all progeny having yellow pods?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 27

Yellow being recessive will express only when both alleles are present. That occurs only when both parents can contribute an allele encoding for the yellow pod. For all progeny to have yellow pods, both parents have to be homozygous for yellow pods.

Biology: CUET Mock Test - 10 - Question 28

I = Inflated, i = constricted. Given that the phenotype of F1 progeny is inflated pods and that the parents are true-breeding, which of the following is not a possible genotype of parents?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 28

Inflated is the dominant phenotype. Hence it can be expressed in two genotypes: II and Ii. The F1 progeny can have it in all the mentioned cases except when both parents are recessive ii.

Biology: CUET Mock Test - 10 - Question 29

What does F in “F1 progeny” stand for?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 29

F1 progeny refers to the first generation of offsprings. This is also termed as the first Filial generation, thereby stating their filial relationship with the true-breeding plants.

Biology: CUET Mock Test - 10 - Question 30

What process needs to be avoided for carrying of efficient crosses?

Detailed Solution for Biology: CUET Mock Test - 10 - Question 30

Self-pollination leads to fertilization by the pollen from the same flower. A cross desires pollination and fertilization by pollen from a different plant. Hence self-pollination needs to be avoided.

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