Question

Which of the following is/are correctly matched?

1. Chromosomes: Thread-like structures present in the nucleus

2. RNA: It is chemically similar to DNA but it contains ribose as its sugar and substitutes the nitrogenous base uracil for thymine.

1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2

Answer 1

Correct Answer - Option 3 : Both 1 and 2

The correct answer is Both 1 and 2.

RNA:

• RNA is the bridge between DNA and protein synthesis.
• RNA is chemically similar to DNA but it contains ribose as its sugar and substitutes the nitrogenous base uracil for thymine. Hence statement 2 is correct.
  • It is single-stranded rather than a double helix.
• To get from DNA requires two major stages, transcription and translation.
• The process from DNA to RNA is known as Transcription.
  • During transcription, a DNA strand provides a template for the synthesis of a complementary RNA strand.
  • Transcription of a gene produces a messenger RNA (mRNA) molecule.
• During translation, the information contained in mRNA is used to determine the amino acid sequence of a polypeptide.
  • Translation occurs at ribosomes.

Chromosomes:

• Chromosomes are thread-like structures present in the nucleus. Hence statement 1 is correct.
• These are nothing but DNA tightly coiled around a protein called histone.
• Chromosomes exist in pairs.
• Human cells contain 23 such pairs or 46 chromosomes.
• Each chromosome is comprised of one super-long DNA molecule.
• The DNA is coiled around histones and then many such histones are packed together to form a chromosome.