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SUMMARY LIFE SCIENCES MATRIC IEB EXAM 2026 QUESTIONS
LATEST 2026 – 2027 VERSION SOLVED QUESTIONS &
ANSWERS
Summary Life Sciences Matric IEB Exam
Questions with Comprehensive Rationales
SECTION 1: DNA, RNA & PROTEIN SYNTHESIS (Questions 1-40)
1. The molecule that carries the genetic code from the nucleus to the cytoplasm for
protein synthesis is:
• A) DNA
• B) mRNA
• C) tRNA
• D) rRNA
Answer: B - Messenger RNA (mRNA) carries the genetic code from DNA in the nucleus
to the ribosomes in the cytoplasm for protein synthesis. DNA (A) remains in the
nucleus. tRNA (C) carries amino acids to the ribosome. rRNA (D) is a structural
component of ribosomes.
2. Which of the following correctly describes the structure of DNA?
• A) A single-stranded helix with uracil bases
• B) A double helix with adenine, guanine, cytosine, and thymine
• C) A double helix with adenine, guanine, cytosine, and uracil
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• D) A single-stranded helix with thymine bases
Answer: B - DNA is a double helix composed of two antiparallel strands held together
by hydrogen bonds between complementary base pairs: adenine-thymine and guanine-
cytosine. It contains thymine (not uracil). Option C describes RNA, and options A and D
are incorrect because DNA is double-stranded.
3. The process by which mRNA is synthesized from a DNA template is called:
• A) Translation
• B) Transcription
• C) Replication
• D) Transformation
Answer: B - Transcription is the process of synthesizing mRNA from a DNA template.
Translation (A) is the synthesis of proteins from mRNA. Replication (C) is the copying of
DNA. Transformation (D) is the uptake of foreign DNA by a cell.
4. The codon AUG on mRNA codes for which amino acid and also serves as the:
• A) Stop codon
• B) Start codon
• C) Anticodon
• D) Termination signal
Answer: B - AUG is the start codon that codes for methionine and initiates protein
synthesis. Stop codons (A) are UAA, UAG, and UGA. Anticodons (C) are found on tRNA.
Termination signals (D) are stop codons.
5. A mutation results in the substitution of one nucleotide in a gene. If the new
codon still codes for the same amino acid, this is called a:
• A) Missense mutation
• B) Nonsense mutation
• C) Silent mutation
• D) Frameshift mutation
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Answer: C - A silent mutation is a nucleotide substitution that does not change the
amino acid due to the degeneracy of the genetic code. Missense mutations (A) change
the amino acid. Nonsense mutations (B) create a stop codon. Frameshift mutations (D)
result from insertions or deletions.
6. The sequence of three nucleotides on tRNA that is complementary to a codon on
mRNA is called a(n):
• A) Codon
• B) Anticodon
• C) Exon
• D) Intron
Answer: B - The anticodon is the three-nucleotide sequence on tRNA that is
complementary to the mRNA codon. Codons (A) are on mRNA. Exons (C) are coding
regions of genes. Introns (D) are non-coding regions.
7. The enzyme responsible for unwinding the DNA double helix during replication
is:
• A) DNA polymerase
• B) Helicase
• C) Ligase
• D) RNA polymerase
Answer: B - Helicase unwinds the DNA double helix during replication. DNA polymerase
(A) synthesizes new DNA strands. Ligase (C) joins Okazaki fragments. RNA polymerase
(D) synthesizes RNA during transcription.
8. Which of the following statements about RNA is TRUE?
• A) RNA is double-stranded and contains thymine
• B) RNA is single-stranded and contains uracil
• C) RNA is double-stranded and contains uracil
• D) RNA is single-stranded and contains thymine
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Answer: B - RNA is typically single-stranded and contains uracil instead of thymine.
DNA is double-stranded and contains thymine. Options A, C, and D are incorrect
descriptions of RNA.
9. The number of chromosomes in a human somatic cell is:
• A) 23
• B) 46
• C) 44
• D) 22
Answer: B - Human somatic (body) cells contain 46 chromosomes (23 pairs). Gametes
(sperm and eggs) contain 23 chromosomes (A). There are 22 pairs of autosomes plus 1
pair of sex chromosomes.
10. The site of protein synthesis in a cell is the:
• A) Nucleus
• B) Ribosome
• C) Mitochondrion
• D) Golgi apparatus
Answer: B - Protein synthesis occurs at the ribosome. The nucleus (A) contains DNA
and is the site of transcription. Mitochondria (C) produce energy. The Golgi apparatus
(D) modifies and packages proteins.
11. The sequence of nucleotides in DNA that codes for a specific protein is called a:
• A) Chromosome
• B) Gene
• C) Genome
• D) Allele
Answer: B - A gene is a sequence of DNA nucleotides that codes for a specific protein.
Chromosomes (A) contain many genes. The genome (C) is the entire set of genetic
material. Alleles (D) are different versions of a gene.
SUMMARY LIFE SCIENCES MATRIC IEB EXAM 2026 QUESTIONS
LATEST 2026 – 2027 VERSION SOLVED QUESTIONS &
ANSWERS
Summary Life Sciences Matric IEB Exam
Questions with Comprehensive Rationales
SECTION 1: DNA, RNA & PROTEIN SYNTHESIS (Questions 1-40)
1. The molecule that carries the genetic code from the nucleus to the cytoplasm for
protein synthesis is:
• A) DNA
• B) mRNA
• C) tRNA
• D) rRNA
Answer: B - Messenger RNA (mRNA) carries the genetic code from DNA in the nucleus
to the ribosomes in the cytoplasm for protein synthesis. DNA (A) remains in the
nucleus. tRNA (C) carries amino acids to the ribosome. rRNA (D) is a structural
component of ribosomes.
2. Which of the following correctly describes the structure of DNA?
• A) A single-stranded helix with uracil bases
• B) A double helix with adenine, guanine, cytosine, and thymine
• C) A double helix with adenine, guanine, cytosine, and uracil
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• D) A single-stranded helix with thymine bases
Answer: B - DNA is a double helix composed of two antiparallel strands held together
by hydrogen bonds between complementary base pairs: adenine-thymine and guanine-
cytosine. It contains thymine (not uracil). Option C describes RNA, and options A and D
are incorrect because DNA is double-stranded.
3. The process by which mRNA is synthesized from a DNA template is called:
• A) Translation
• B) Transcription
• C) Replication
• D) Transformation
Answer: B - Transcription is the process of synthesizing mRNA from a DNA template.
Translation (A) is the synthesis of proteins from mRNA. Replication (C) is the copying of
DNA. Transformation (D) is the uptake of foreign DNA by a cell.
4. The codon AUG on mRNA codes for which amino acid and also serves as the:
• A) Stop codon
• B) Start codon
• C) Anticodon
• D) Termination signal
Answer: B - AUG is the start codon that codes for methionine and initiates protein
synthesis. Stop codons (A) are UAA, UAG, and UGA. Anticodons (C) are found on tRNA.
Termination signals (D) are stop codons.
5. A mutation results in the substitution of one nucleotide in a gene. If the new
codon still codes for the same amino acid, this is called a:
• A) Missense mutation
• B) Nonsense mutation
• C) Silent mutation
• D) Frameshift mutation
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Answer: C - A silent mutation is a nucleotide substitution that does not change the
amino acid due to the degeneracy of the genetic code. Missense mutations (A) change
the amino acid. Nonsense mutations (B) create a stop codon. Frameshift mutations (D)
result from insertions or deletions.
6. The sequence of three nucleotides on tRNA that is complementary to a codon on
mRNA is called a(n):
• A) Codon
• B) Anticodon
• C) Exon
• D) Intron
Answer: B - The anticodon is the three-nucleotide sequence on tRNA that is
complementary to the mRNA codon. Codons (A) are on mRNA. Exons (C) are coding
regions of genes. Introns (D) are non-coding regions.
7. The enzyme responsible for unwinding the DNA double helix during replication
is:
• A) DNA polymerase
• B) Helicase
• C) Ligase
• D) RNA polymerase
Answer: B - Helicase unwinds the DNA double helix during replication. DNA polymerase
(A) synthesizes new DNA strands. Ligase (C) joins Okazaki fragments. RNA polymerase
(D) synthesizes RNA during transcription.
8. Which of the following statements about RNA is TRUE?
• A) RNA is double-stranded and contains thymine
• B) RNA is single-stranded and contains uracil
• C) RNA is double-stranded and contains uracil
• D) RNA is single-stranded and contains thymine
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Answer: B - RNA is typically single-stranded and contains uracil instead of thymine.
DNA is double-stranded and contains thymine. Options A, C, and D are incorrect
descriptions of RNA.
9. The number of chromosomes in a human somatic cell is:
• A) 23
• B) 46
• C) 44
• D) 22
Answer: B - Human somatic (body) cells contain 46 chromosomes (23 pairs). Gametes
(sperm and eggs) contain 23 chromosomes (A). There are 22 pairs of autosomes plus 1
pair of sex chromosomes.
10. The site of protein synthesis in a cell is the:
• A) Nucleus
• B) Ribosome
• C) Mitochondrion
• D) Golgi apparatus
Answer: B - Protein synthesis occurs at the ribosome. The nucleus (A) contains DNA
and is the site of transcription. Mitochondria (C) produce energy. The Golgi apparatus
(D) modifies and packages proteins.
11. The sequence of nucleotides in DNA that codes for a specific protein is called a:
• A) Chromosome
• B) Gene
• C) Genome
• D) Allele
Answer: B - A gene is a sequence of DNA nucleotides that codes for a specific protein.
Chromosomes (A) contain many genes. The genome (C) is the entire set of genetic
material. Alleles (D) are different versions of a gene.
