Topics-
Products +
     

DNA Questions and Answers (Q&A)

The correct answer is option A – Make it possible to create huge numbers of copies of tiny pieces of DNA. Polymerase Chain Reaction (PCR) is the most common lab technique that we use to amplify DNA. We use this technique mostly in molecular biology for creating multiple copies of DNA from a sample. The process of PCR occurs in 3 phases . The denaturation phase, annealing phase and the extension (elongation) phase. The first phase is the denaturation phase. In this phase; temperature is raised to 92 degree Celsius.

The heat helps breakdown hydrogen bonds in the strands. In the annealing phase, the temperature is lowered to about 50 to 60 degree Celsius. This will allow primers to attach to specific regions on the DNA through hydrogen bonding. The elongation step is the final step in polymerase chain reaction. The temperature is raised again to allow the synthesis of new DNA strands.

1 Answer

The correct answer to the question is option D – UGG. The stop codon is nucleotide triplets that are found in mRNA. Stop codon serve as signals for the termination of translation. These codons are also known as termination codons or nonsense codons. There are three standard stop codons found in mRNA.

They are UAG, UAA, and UGA. UAG is known as an amber stop codon, UAA is an ochre codon, and UGA is known as an umber stop codon. Stop codon work by binding to release factors. This causes dissociation of ribosomal subunits, and this will cause the release of the amino acid chain produced. Of all the options listed above, only option D (UGG) is not a stop codon.

1 Answer

The correct answer is option CA– Watson and Crick. The two scientists responsible for the discovery of the structure of DNA are James Watson and Francis Crick. The double helix structure was first described in 1953. James, Crick, and Wilkins were awarded a Noble Prize in Medicine in 1962 for this discovery. Maurice Wilkins also contributed to this discovery. However, there was someone else that contributed to the discovery of the double helix structure. In most cases, this person isn’t acknowledged.

Rosalind Franklin was not recognized for her contribution. She died before the Noble price was won. She died of ovarian cancer at the age of 37. This discovery is one of the most significant discoveries of mankind. The double helix structure of DNA shows the two linear strands of DNA that run opposite to each other and twisted together. These strands are held together by chemical bonds.

1 Answer

Polypeptide. Another name for protein is a polypeptide. Polypeptides are chains of amino acids that are held together by amine bonds. Proteins are made up of many polypeptides. Proteins perform various functions in the body. They function as transporting molecules, provide structural support to a cell, catalyze metabolic reactions (act as enzymes), cell signaling, immune response, and they play significant roles in the cell cycle.

Proteins are different from one another based on the sequence of amino acids they have. These amino acids are held together by peptide bonds. A peptide that contains two amino acid residues is termed dipeptide. A peptide with three amino acids is called tripeptide. Peptides with less than 20 to 30 residues are generally known as short polypeptides or oligopeptides.

1 Answer

The correct answer to the question is option C – To bring the DNA message to the ribosome. Messenger RNA, commonly referred to as mRNA, is produced during transcription. It carries genetic information from DNA to the ribosome. It acts as an intermediary between the genetic material in DNA and amino acids of proteins. It is synthesized by RNA polymerase II during transcription. mRNA is transported outside the nucleus where it meets with the ribosome (cellular machinery for assembling amino acids) and transfer RNA to begin the process of translation (protein synthesis). mRNA contains nucleotides known as codons that are complementary to the nucleotide sequence present on the template strand of the DNA transcribed. Transfer RNA (tRNA) binds to the specific codon on the mRNA, and this begins the process of translation.

1 Answer

The correct answer is option B – AUUCGUAAGGCUC The corresponding sequence to the DNA sequence (TAAGCATTCCGAG) mentioned above as a result of transcription is AUUCGUAAGGCUC. This question is testing your knowledge of base pairing specifically in transcription. Transcription is the process whereby the DNA sequence of a gene is copied to produce mRNA which is needed for protein synthesis.

DNA sequence uses complementary base paring of guanine (G) and cytosine (C), thymine (T) and adenosine (A) while on the mRNA produced you have nucleotides such as adenine, uracil, cytosine and guanine. Thymine is replaced by Uracil. Since DNA sequence is complementary to mRNA produced. A on the DNA on the DNA sequence will be matched by U on mRNA and G on DNA sequence is matched by C on MRNA.

1 Answer

The correct answer to this question is option B. Eukaryotes often express a significantly smaller percentage of their genes in gene expression because eukaryotic cells are specialized and they only need to express specific regions of the DNA to code for proteins. The process of controlling the gene in specific DNA region expressed is termed gene regulation.

The genes expressed largely depend on the chemical signal that binds to its receptors to cause a change in gene expression. These chemical signals will activate certain transcription factors that will bind to specific DNA sequence and this leads to transcription. In prokaryotes, the DNA is housed within one chromosome and by defaults all the genes present in the cell are on. Transcription and translation also occur simultaneously in the cytoplasm.

1 Answer

But not all organisms use DNA, some use RNA. This question is wrong

1 Answer

The correct answer to the question is option C – 23 pairs. In humans, our cells have 23 pairs of chromosomes and a total of 46 chromosomes. Twenty-two pairs of these chromosomes are known as autosomes, and the last pair of the chromosome is termed sex chromosomes. The autosomes look similar for males and females. For the sex chromosomes, females have two copies of X chromes, while males have one Y and one X chromosome.

We inherit 23 chromosomes from each parent, 22 autosomes and one X chromosomes from mother and 22 autosomes and either X or Y sex chromosomes from father. Option A (46 pairs) is wrong because the human body cell has 23 pairs, and not 46 pairs Option B (12 pairs) is wrong because the human cell does have more than 12 pairs chromosomes. Option D (8 pairs) is wrong because the human body cell has more than eight pairs of chromosomes.

1 Answer

Looking at the DNA sequence provided (5’ATGGTCAGT3’), we can tell what the complementary DNA sequence will be. This question is testing your knowledge on complementary base pairing in strands of DNA. Complementary base pairing in DNA is when guanine forms three hydrogen bonds with cytosine and adenine forms three hydrogen bonds with thymine.

This rule states that adenine can ONLY bind to thymine, and guanine can ONLY bind to guanine. Therefore, adenine on one strand will be complementary to thymine on the second strand, and the same goes for cytosine and guanine. If one strand is positioned in 5’ to 3’ direction, the other strand is positioned in 3’ to 5’ direction. Therefore, options A, B, and D are incorrect.

1 Answer

Loading, please wait...

Email Sent
We have sent an email to your address "" with instructions to reset your password.