Molecular Genetics

Question 1

discovered NUCLEIN in the cell nucleus

Answer 1

Friedrich Miescher

Question 2

The major component of nuclein is

Answer 2

DNA.

Question 3

basic structure of DNA

Answer 3

• Phosphate backbone
• Deoxyribose sugar
• Nitrogen bases

Question 4

noticed that alkaptonuria seemed to behave like a Mendelian recessive trait. Alkaptonuria is a disease caused by deficiency of the enzyme, Homogentisate 1,2-dioxygenase (HGD) leading to failure of tyrosine to be metabolized which in turn leads to accumulation of Homogentisic acid, leading to a black urine. He postulated, that a defective gene is responsible for a defective enzyme.

Answer 4

Archibald Garrod

Question 5

proved the relationship of genes and proteins from their experiments on a mold known as Neurospora. They induced mutagens to a specific gene of the mold, which can block the metabolic pathway. Adding the intermediate product of the disrupted pathway restored normal growth of the mold.
They discovered where the defective gene was. This experiment led to the “one gene, one enzyme hypothesis which means that a gene is responsible for synthesizing a protein called enzyme.

Answer 5

George Beadle & E.L. Tatum

Question 6

built the model of DNA

Answer 6

James Watson and Francis Crick

Question 7

built the model of DNA

Answer 7

James Watson and Francis Crick

Question 8

James Watson and Francis Crick built the model of DNA based on the X-ray photos collected by

Answer 8

Rosalind Franklin and Maurice Wilkins.

Question 9

believed that ribosomes are nonspecific translation machines that can make unlimited number of proteins, according to the instructions in the mRNAs that visit the ribosomes

Answer 9

Francois Jacob and Sydney Brenner

Question 10

cracked the genetic code. They independently discovered that three bases constitute a codon, which coded for an amino acid. Out

Answer 10

Marshal Nirenberg and Gobind Khorana