Chapter 13, Problem 25A

Summary Introduction

Introduction:

The Human Genome Project (HGP) was undertaken to determine the sequence of nucleotides in human DNA and to identify all its genes. Though the project was over in 2003, the data obtained from the project is still being analyzed. The scientists had to decode the genetic code in the human genome.

Answer to Problem 25A

Correct answer :

The correct answer is option D. The human genome contains nucleotide sequences that all code for proteins

Explanation of Solution

Explanation/justification for the correct answer:

Option D. The human genome contains nucleotide sequences that all code for proteins − After sequencing the entire human genome, the scientists found that less than two percent of all the nucleotides in the human genome code for all the proteins in the body. Hence, there are long stretches of DNA that have no direct function. These regions are called noncoding sequences. So this statement about human genome is wrong. Hence, this is the correct option.

Explanation for incorrect answer:

Option A. The human genome contains approximately 25,000 genes− The goal of HGP was to determine the nucleotide sequences that make the human DNA and to identify all of the approximately 20,000 to 25,000 human genes. This is true of human genome. Hence, this is not the correct option.

Option B. The human genome contains long stretches of DNA with no known function- After sequencing the entire human genome, the scientists found that there are long stretches of DNA that have no direct function. These regions are called noncoding sequences.

Hence, this is not the correct option.

Option C. The human genome was sequenced by scientists from around the world− The HGP was an international project that was sequenced by scientists from around the world. Hence, this is not the correct option.