Tag: structure of dna and rna

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Multiple choice structure of dna and rna nucleic acids and polynucleotides nucleic acids and protein synthesis molecular biology biology

Select the correct option

  1. Direction of RNA Synthesis ----- Direction of reading of template DNA Strand

    3 5------5 3

  2. Direction of RNA Synthesis ----- Direction of reading of template DNA Strand

    5 3------5 3

  3. Direction of RNA Synthesis---- Direction of reading of template DNA Strand

    3 5------3 5

  4. Direction of RNA Synthesis - ---- Direction of reading of template DNA Strand

    5 3 ----- 3 5
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

RNA synthesis occurs in the 5' to 3' direction, and the template DNA strand is read in the 3' to 5' direction to ensure antiparallel alignment.

Multiple choice structure of dna and rna nucleic acids and polynucleotides nucleic acids and protein synthesis molecular biology biology

Identify the DNA segment which is not pallindromic

  1. 5'-GAATTC -3'

    3'-CTTAAG-5'

  2. 5'-CCCGGG-3'

    3'-GGGCCC-5'

  3. 5-GGATCC-3'

    3' GGTACC-5'

  4. 5'-GCGGCCGC-3'

    3-CGCCGGCG-5'
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A palindromic DNA sequence reads the same in the 5' to 3' direction on both strands. Option C is not palindromic because the complementary strand of 5'-GGATCC-3' is 3'-CCTAGG-5', which does not match the provided sequence.

Multiple choice structure of dna and rna nucleic acids and polynucleotides nucleic acids and protein synthesis molecular biology biology

The terminator/stop codons UGA, UAG and UAA

  1. Initiate translation

  2. Do not code for any amino acid

  3. Code for only one amino acid

  4. Code for more than one amino acid

  5. Initiate transcription
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

UGA, UAG, and UAA are known as stop or nonsense codons. They signal the termination of protein synthesis and do not code for any amino acid.

Multiple choice structure of dna and rna nucleic acids and polynucleotides nucleic acids and protein synthesis molecular biology biology

Which one of the following alternations in DNA is likely to be lethal?

  1. Substitution of adenine for cytosine

  2. Substitution of methyl cytosine for cytosine

  3. Deletion of thee nucleotides

  4. Insertion of one nucleotide
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Insertion or deletion of a single nucleotide shifts the reading frame of the entire downstream genetic sequence, resulting in a frameshift mutation that drastically alters all subsequent amino acids and is usually lethal or severely dysfunctional. Substitutions or deletions of three nucleotides affect only single amino acids or remove a single codon.

Multiple choice structure of dna and rna nucleic acids and polynucleotides nucleic acids and protein synthesis molecular biology biology

An increased melting temperature for duplex DNA results from a high content of _________________.

  1. Adenine$+$ guanine
  2. Cytosine$+$thymine
  3. Cytosine$+$guanine
  4. Adenine$+$ cytosine
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cytosine and guanine base pairs are held together by three hydrogen bonds, whereas adenine and thymine pairs have only two. Consequently, DNA strands with a higher G-C content require more thermal energy to break the hydrogen bonds, resulting in an increased melting temperature.

Multiple choice structure of dna and rna nucleic acids and polynucleotides nucleic acids and protein synthesis molecular biology biology

The successive nucleotides of RNA are covalently linked through ______________.

  1. Glycoside bonds

  2. Hydrogen bonds

  3. Phosphodiester bonds

  4. Peptide bonds
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Successive nucleotides in both RNA and DNA chains are covalently joined together by phosphodiester bonds, which form between the 3 prime carbon of one sugar and the 5 prime carbon of the next. Glycoside bonds link bases to sugars, and hydrogen bonds hold complementary strands together non-covalently.

Multiple choice structure of dna and rna nucleic acids and polynucleotides nucleic acids and protein synthesis molecular biology biology

In nematode resistance by RNA interference , some specific genes were introduced which form ds RNA these were introduced in ?

  1. Nematode

  2. Host plant

  3. Agrobacteroum

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

To protect plants from parasitic nematodes via RNA interference, transgenic host plants are engineered to express specific double-stranded RNA matching nematode genes. When the nematode feeds on the host plant, the ingested dsRNA triggers RNAi and silences the essential parasite genes.

Multiple choice structure of dna and rna nucleic acids and polynucleotides nucleic acids and protein synthesis molecular biology biology

Okazaki segments develop in

  1. Newly synthesised leading strand

  2. Newly synthesised lagging strand

  3. Master strand

  4. Template strands of DNA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During DNA replication, the lagging strand is synthesized discontinuously in short segments known as Okazaki fragments because DNA polymerase can only synthesize in the 5 prime to 3 prime direction. The leading strand, by contrast, is synthesized continuously.