12 Biology Answer Key Paper Code 57/7/1
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Now We are bringing to you CBSE Class 12 Biology Answer Key Paper Code 57/7/1. These answer keys have been prepared by expert with years of teaching experience to Class 12 students. Though they are unofficial keys, they have been prepared with due care, in order to give you an estimate for your score in the exam. These answer keys of paper code 57/7/1 focus on MCQs appeared in the exam.
So, let’s start.
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Q.1 What are minisatellites?
ANSWER
Answer: Option (C) is correct – Short non-coding repetitive sequences forming a large portion of eukaryotic genome.
Q.2 Identify the incorrect statement regarding PCR.
ANSWER
Answer: Option (C) is correct – Annealing is required to separate both the strands of template DNA
Q.3 The following information is about drugs and tobacco. Select the correct statement from the options given below:
ANSWER
Answer: Option (D) is correct – Morphine is often given to persons who have undergone surgery as a painkiller.
Q.4 Given below are the events that are observed in an artificial hybridization programme. Arrange them in the correct sequential order:
i.Re-bagging
ii.Selection of parents
iii.Bagging
iv.Dusting the pollens on stigma
v.Emasculation
vi.Collection of pollens from male parents.
ANSWER
Answer: Option (A) is correct – ii,v,iii, vi,iv,i
Q.5 Which of the following conditions correctly describes the manner of determining the sex in the given options?
ANSWER
Answer: Option (B) is correct – XO type of chromosomes determine male sex in grasshoppers
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Q.6 Choose the option that correctly describes the gynoecium of Michelia.
ANSWER
Answer: Option (A) is correct – Multicarpellary, Apocarpous
Q.7 The given graph shows the range of variation among population members, for a trait determined by multiple genes. If this population is subjected to disruptive selection for several generations, which of the following distribution is most likely to result?
ANSWER
Answer: Option C is correct.
Q.8 Which of the following immune system components does not correctly match with its respective role?
ANSWER
Answer: Option (B) is correct – Macrophages – Mucus-secreting cells that trap microbes entering into the body.
Q.9 Which one of the following is not the product of transgenic experiments?
ANSWER
Answer: Option (D) is correct = production of insulin by rDNA technique
Q.10 A biologist studied the population of rats in a granary. He found the average natality was 280, average mortality was 200, immigration was 40 and emigration was 50. The net increase in population is:
ANSWER
Answer: Option (B) is correct – 70
Q.11 India has only 2.4% of the world’s land area but its share of the global species diversity is:
ANSWER
Answer: Option (A) is correct – 8.1%
Q.12 Out of the following, select the correct match:
ANSWER
Answer: Option (B) is correct
ELISA – Antigen antibody interaction
Q.13 Assertion (A): Swiss cheese is characterized by large holes due to C02 production.
Reason (R): It is ripened by growing a specific fungi.
ANSWER
Answer: Option (C) is correct – Assertion is true but Reason is false.
Q.14 Assertion (A): Replication of DNA takes place in S phase of the cell cycle.
Reason (R): DNA replication and cell division cycle should be highly coordinated.
ANSWER
Answer: Option (A) is correct – Both Assertion and Reason are true and Reason is correct explanation of Assertion.
Q.15 Assertion (A): A male individual always inherits haemophilia from his mother.
Reason (R): The gene for haemophilia lies on X-chromosome.
ANSWER
Answer: Option (A) is correct – Both Assertion and Reason are true and Reason is correct explanation of Assertion.
Q.16 Assertion (A): A piece of DNA inserted into an alien organism generally does not replicate, if not inserted into a chromosome.
Reason (R): Chromosomes have specific sequences called ori region, where DNA replication is initiated.
ANSWER
Answer: Option (A) is correct – Both Assertion and Reason are true and Reason is correct explanation of Assertion.
We hope that the above answer key will help you estimate your marks in your exam for the time being. These answer keys are without explanation for now as we are providing them in very less time. The explanation will be added in coming days.
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