Question

How many base pairs are in a haploid set of human chromosomes :

• A. 3 million
• B. 3 billion
• C. 3 trillion
• D. 1 trillion

Hint:

Just remember: Human = 3 Billion base pairs (per haploid genome) = 23 chromosomes. E. coli (a typical bacterium) has about 4.6 Million base pairs.

Answer 1

The Correct Option is B

Step 1: Concept:
This is a factual question regarding the size of the human genome. The human genome is the complete set of nucleic acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei.

Step 2: Step-by-step Explanation:

• A single, haploid set of human chromosomes consists of 23 chromosomes (22 autosomes and 1 sex chromosome).

• The total length of the human reference genome (representing a haploid set) was mapped during the Human Genome Project.

• The total number of DNA base pairs in this haploid set is approximately 3.2 billion base pairs ($3.2 \times 10^9$ bp).

• A full diploid somatic cell contains roughly twice that amount (about 6.4 billion base pairs).

• Among the given choices, 3 billion is the correct order of magnitude for a haploid set.

Step 3: Final Answer:
The haploid human genome contains approximately 3 billion base pairs. This matches option (B).