Chromosomes and DNA

Master high-yield MDCAT Biology MCQs on DNA replication, transcription, and genetics. Molecular Genetics Practice Test (PMDC test questions) to boost your entry test aggregate! MDCAT solved biology past paper questions, Molecular biology entry test preparation Pakistan, DNA structure and genetic code MCQs for MDCAT. Let us start the Online Molecular Genetics Practice Test now

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• Transcription starts at
• A molecule of tRNA has the anticodon sequence UAC. What will be the corresponding nucleotide sequence in the DNA?
• During transcription, the nucleotide sequence of the DNA strand that is being coded is ATACG; then the nucleotide sequence in mRNA would be
• Transcription occurs along a —————- template, forming an mRNA in the —————- direction
• When out of 64 codons, 61 codons code for 20 types of amino acids, it is called
• The model of DNA replication in which one strand is conserved, and the other is synthesized is
• If the genetic code is made up of three nucleotides, then the total possible genetic code will be
• In translation, the terminating codon is
• RNA polymerase attaches to the ————— site on RNA
• TATAAT box in eukaryotes is present —————- nucleotides before the start of transcription
• Who for the first time checked the 64 nucleotides genetic code in lab
• AUG is the start codon and carries ———— amino acid during translation of mRNA
• According to the Watson-Crick model, what is the distance between two consecutive base pairs in a DNA double helix?
• If a double-stranded DNA sample contains 28% Cytosine, what is the expected percentage of Adenine in the same sample?
• Which histone protein binds to the linker DNA outside the core nucleosome octamer?
• What is the approximate diameter of a nucleosome core particle without the linker DNA?
• A chromosome with a centromere positioned near one end, producing one extremely short arm (p) and one long arm (q), is classified as:
• Which chromosomal disorder results from non-disjunction leading to a trisomy of sex chromosomes with a karyotype of 47,XXY?
• In prokaryotic DNA replication, which enzyme removes RNA primers and fills the gaps with complementary DNA nucleotides?
• If $E.\ coli$ grown in heavy nitrogen ($^{15} N$) is transferred to light nitrogen ($^{14} N$) for two generations of replication, what percentage of DNA molecules will be hybrid ($^{15} N/^{14}N$)?

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Challenge your molecular biology knowledge with this 20-question quiz. Genetics MCQs MDCAT Quiz Covers DNA double helix structure, Okazaki fragments, genetic code degeneracy, mutations, and eukaryotic translation. Let us start with the online Molecular Biology Genetics MCQS MDCAT Quiz Preparation Quiz now

Online Molecular Biology & Genetics MCQs MDCAT Quiz

• UGA codon in mitochondria reads
• If the DNA in all of the cells of an adult human were lined up end to end, it would stretch nearly
• The number of stop codons that do not code for any amino acids is
• The number of triplet codons having all three bases the same in 64 triplet codons is
• In a nucleotide having a cytosine base and linked to sugar by a glycosidic bond at carbon number
• The DNA molecule had a shape of a helix with a diameter of
• The diameter of the DNA double helix remains constant because of
• Length of Okazaki fragments in eukaryotes is a bout
• Which of the following enzymes is present at the replication fork
• The codons which code for the same amino acid are called
• In RNA, thymine is replaced by
• Which of the following RNAs picks up a specific amino acid from the amino acid pool in the cytoplasm to the ribosome during protein synthesis
• Which of the following is non-genetic and is utilized for protein synthesis
• Each amino acid in a protein is specified by
• The three-nucleotide codon system can be arranged into ————— combinations
• What would happen if, in a gene encoding a polypeptide of 50 amino acids, the 25th codon UAU is mutated to UAA?
• The biological process shown in the diagram is
• The two polynucleotide chains in DNA are
• Which of the following is correct regarding the genetic code
• The new strand synthesized in small pieces and then joined together during DNA replication is called

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Prepare for MDCAT 2026 with this Chromosomes and DNA Quiz featuring 20 important Biology MCQs on DNA structure, RNA, genetic code, DNA replication, transcription, translation, nucleotide bonding, hydrogen bonding, DNA ligase, DNA polymerase, codons, tRNA, and protein synthesis. Test your conceptual understanding of molecular biology and identify areas that need further revision.

This MDCAT Biology quiz includes questions covering important concepts such as DNA and RNA bases, complementary base pairing, termination codons, genetic code, amino acids, mRNA processing, tRNA, DNA replication enzymes, nucleotide addition, DNA ligase, and hydrogen bonds between nitrogenous bases. It is suitable for students preparing for MDCAT 2026, medical college entrance tests, and Biology examinations.

Chromosomes and DNA Quiz for MDCAT with Answers

1. Which of the following factors is responsible for joining the small subunit to mRNA
2. Which of the following is a termination codon
3. In bacteria, newly synthesized mRNA is released in
4. The base sequence ATTG on DNA specifies the sequence for RNA
5. The number of amino acids commonly used to synthesize proteins in living things?
6. What is the effect of the enzyme DNA ligase?
7. Biochemical analysis of DNA shows that cytosine forms 40% of nitrogenous bases; what will be the percentage of adenine
8. Which of the following is present in both DNA and RNA
9. Which of the following bases is never found in RNA
10. The process of nucleotide addition is only done by
11. In centrifugation, the gel is used
12. Adenine forms how many hydrogen bonds with thymine
13. When two nucleotides join each other, what type of bond is formed
14. Which of the following bonds exists between the bases in the DNA helix
15. The enzyme controls the unwinding of the double helix
16. Human cells contain about ————— kinds of tRNA
17. Polymerase only adds nucleotides on 3 direction when —————— is attached to the parent strand
18. Which of the following is not a stop codon?
19. The cap and tail save the mRNA from a variety of
20. Genetic code is

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