Concept explainers
The experiments with nutritional mutants in Neurospora by Beadle and Tatum provided evidence that
a. bread mold can be grown in a lab on minimal media.
b. X-rays can damage DNA.
c. cells need enzymes.
d. genes specify enzymes.
Introduction:
To identify the working nature of genes, scientists from all over the world conducted various experiments. The results revealed by them include, the functions controlled by the genes and the enzymes specified by the genes.
Answer to Problem 1U
Correct answer:
The experiments with nutritional mutants in Neurospora by Beadle and Tatum provided evidence that genes specify enzymes. Therefore, option d. is correct.
Explanation of Solution
Reason for the correct statement:
Beadle and Tatum showed that genes specify enzymes. In neurospora, each enzyme of the arginine pathway was encoded by a separate gene. The mutant species of neurospora were unable to synthesize arginine. Beadle and Tatum found that specific enzymes controlled by specific genes were absent in the mutant neurospora. They proposed the one gene-one enzyme hypothesis.
Option d. is given as "genes specify enzymes".
As, “the experiments with nutritional mutants in Neurospora by Beadle and Tatum provided evidence that genes specify enzymes”, it is the right answer.
Hence, the option d. is correct.
Reasons for the incorrect statements:
Option a. is given as “bread mold can be grown in a lab on minimal media”.
In the experiments conducted by Beadle and Tatum, bread mold was grown to determine the enzymes specific for the growth. So, it is a wrong answer.
Option b. is given as “X-rays can damage DNA”.
The experiments conducted by Beadle and Tatum to determine the limiting factors for specific enzymes and not to determine what X-rays do to the DNA. So, it is a wrong answer.
Option c. is given as “cells need enzymes”.
The experiments conducted by Beadle and Tatum were performed to determine the limiting factors, which control synthesis of enzymes responsible for specific functions. So, it is a wrong answer.
Hence, the options a., b., and c. are incorrect.
The experiments with nutritional mutants in Neurospora by Beadle and Tatum provided evidence that genes specify enzymes.
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Chapter 15 Solutions
EBK BIOLOGY
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