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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#1. If a double-stranded DNA sample contains 28% Cytosine, what is the expected percentage of Adenine in the same sample?
By Chargaff’s rule, %C=%G=28%, total C+G=56%. The remaining 44% is split equally between Adenine and Thymine (44%/2=22%)
#2. Transcription occurs along a —————- template, forming an mRNA in the —————- direction
#3. The model of DNA replication in which one strand is conserved, and the other is synthesized is
#4. In translation, the terminating codon is
#5. AUG is the start codon and carries ———— amino acid during translation of mRNA
#6. If the genetic code is made up of three nucleotides, then the total possible genetic code will be
#7. What is the approximate diameter of a nucleosome core particle without the linker DNA?
The fundamental “beads-on-a-string” nucleosome fiber has a diameter of roughly 10–11 nm, which further condenses into a 30 nm fiber
#8. Transcription starts at
#9. Who for the first time checked the 64 nucleotides genetic code in lab
#10. During transcription, the nucleotide sequence of the DNA strand that is being coded is ATACG; then the nucleotide sequence in mRNA would be
#11. A molecule of tRNA has the anticodon sequence UAC. What will be the corresponding nucleotide sequence in the DNA?
#12. When out of 64 codons, 61 codons code for 20 types of amino acids, it is called
#13. 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 ($^{15} N/^{14}N$)?
#14. Which chromosomal disorder results from non-disjunction leading to a trisomy of sex chromosomes with a karyotype of 47,XXY?
47,XXY is caused by meiotic non-disjunction of sex chromosomes. Turner syndrome is 45,X, and Down syndrome is Trisomy 21
#15. According to the Watson-Crick model, what is the distance between two consecutive base pairs in a DNA double helix?
One full turn of DNA is 3.4 nm long and contains 10 base pairs, making the distance between adjacent base pairs 3.4 nm/10=0.34 nm
#16. A chromosome with a centromere positioned near one end, producing one extremely short arm (p) and one long arm (q), is classified as:
Acrocentric chromosomes have centromeres located near one end (forming tiny satellites/short arms). Telocentric chromosomes have centromeres at the absolute tip (not found in human karyotypes)
#17. TATAAT box in eukaryotes is present —————- nucleotides before the start of transcription
#18. Which histone protein binds to the linker DNA outside the core nucleosome octamer?
The nucleosome octamer consists of two copies each of H2A, H2B, H3, and H4. H1 sits externally on the linker DNA to seal the wrapped DNA
#19. RNA polymerase attaches to the ————— site on RNA
#20. In prokaryotic DNA replication, which enzyme removes RNA primers and fills the gaps with complementary DNA nucleotides?
DNA Polymerase I exhibits 5′→3′exonuclease activity to chew away the RNA primer and replace it with DNA. DNA Polymerase III performs the main bulk of elongation.
Online Molecular Genetics Practice Test for MDCAT Preparation
- 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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