Biology Specimen Paper Sec-A 2023 Solved for ISC Class-12

Biology Specimen Paper Sec-A 2023 Solved for ISC Class-12.  Step by step solutions as council prescribe guideline of model sample question paper.  During solutions of Biology specimen paper we explain with figure , graph, table whenever necessary so that student can achieve their goal in next upcoming exam of council. Visit official website CISCE for detail information about ISC Board Class-12.

Biology Specimen Paper Sec-A 2023 Solved for ISC Class-12

Board ISC
Class  12th (xii)
Subject Biology (Section-A)
Topic ISC Specimen Paper Solved
Syllabus  on Revised syllabus
Session 2022-23

Biology Specimen Paper Sec-A 2023 Solved for ISC Class-12

Warning :- before viewing solution view Question Paper


Biology Paper 1 (Theory)

Maximum Marks: 70
Time Allowed: Three hours

(Candidates are allowed additional 15 minutes for only reading the paper. They must NOT start writing during this time).

  • This paper is divided into four sections – A, B, C and D.
  • Answer all questions.
  • Section A consists of one question having sub-parts of one mark each.
  • Section B consists of seven questions of two marks each.
  • Section C consists of nine questions of three marks each, and
  • Section D consists of three questions of five marks each.
  • Internal choices have been provided in two questions each in Section B, Section C and Section D.
  • The intended marks for questions are given in brackets [ ].


ISC Class-12 Biology Specimen Paper 2023 Solved sec-A

Question 1: Answer the following questions briefly.

(i) Name the type of bioreactor which provides greater surface area for oxygen transfer.

Ans:  Sparged stirred-tank bioreactor has increased surface area for oxygen transfer than simple stirred-tank.

(ii) Name the causative agent of genital warts.

Ans :  Causes: Human papillomavirus infection

(iii) If a segment of double-stranded DNA has 18% thymine, calculate the percentage of cytosine in the DNA.

Ans :  32%

(iv) A woman has normal vision, but her father is colourblind. If she marries a colourblind man, what is the probability of her son being colourblind?

Ans :  50%’.

(v) What are Ramsar sites?

Ans :  Ramsar Sites are wetlands of international importance that have been designated under the criteria of the Ramsar Convention on Wetlands for containing representative, rare or unique wetland types or for their importance in conserving biological diversity

(vi) Define standing state in an ecosystem.

Ans– Standing state can be defined as the amount of inorganic nutrients found in an ecosystem.  Represents the part of non-living matter And usually occurs in the growth medium of producers. It determines the productivity of the ecosystem.

(vii) Name the toxin which is responsible for causing the symptoms of malaria.

Ans:  toxins is hemozoin 

(viii) Name the bond which exists between chain-A and chain-B of human insulin.

Ans :  The insulin molecule consists of two peptide chains, the A-chain and the B-chain, linked by two disulfide bonds

(ix) Which row is correct with respect to the features of Neutrophils and B-lymphocytes?

Chart see in question paper.

Ans – (b) II

(x) How many ova and sperms would be produced from 50 primary oocytes and 50 primary spermatocytes during gametogenesis?

(a) 100 ova, 50 sperms
(b) 100 ova, 200 sperms
(c) 50 ova, 200 sperms
(d) 50 ova, 100 sperms

Ans:  (d) 50 ova, 100 sperms

(xi) Which one of the following is a palindromic sequence?

(a) 5’-CGTATG-3’ 3’-CGAATG-5’
(b) 5’-CGAATG-3’ 3’-GCATAC-5’
(c) 5’-GAATTC-3’ 3’-CTTAAG-5’
(d) 5’-CGAATG-3’ 3’-CTTAAG-5’

Ans– (c) 5’-GAATTC-3’ 3’-CTTAAG-5’

(xii) Assertion: Energy value of biogas is lower than that of organic matter.

Reason: Biogas minimises the chances of spread of faecal pathogens.

(a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

(b) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.

(c) Assertion is true but Reason is false.

(d) Both Assertion and Reason are false.

Ans:- (a) Both Assertion and Reason are true,

(xiii) Give one significant contribution of each of the following scientists:

(a) S. Cohen—first scientists to transplant genes from one living organism to another, a fundamental discovery for genetical engineering.

(b) H. Boyer—demonstrated the possibility of producing recombinant DNA in bacteria in 1973. This they did by combining a gene for frog ribosomal RNA with a bacterial plasmid which was then put into a strain of E-coli for expression

(xiv) Give a term for the following: 

(a) The technique used to amplify a gene.—Polymerase chain reaction (PCR)

(b) The technique used for early diagnosis of HIV infection–ELISA Test

(xv) Expand the following abbreviations:

(a) ICSI—Intracytoplasmic sperm injection

(b) IUCD—Intrauterine contraceptive device

(xvi) Give a reason for each of the following:

(a) A person with cuts and bruises following an accident is administered tetanus anti-toxin.

Ans:– Hence, a doctor administers antitoxin and not a tetanus vaccine to a child injured in a roadside accident with a bleeding wound because Clostridium tetani could enter his body through the wound.

(b) Origin of life is not possible under the present atmospheric conditions.

Ans:– Life cannot originate from inorganic materials at present due to the oxidising atmosphere. The earth is highly rich in oxygen today which does not provide the suitable environment for evolution.

–: End of Biology Specimen Paper Sec-A 2023 Solved for ISC Class-12 :–

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