Lecture 1

Question 1

What did they know about genetics in 1940?

Answer 1

1. Enzymes catalyse cellular reactions
2. Mutations affect phenotypes
3. Genes are on chromosomes

Question 2

What didn’t they know about genetics in 1940?

Answer 2

That DNA is the genetic material

Question 3

What organism was used in the experiment?

Answer 3

Neurosproa (fungus)
Bread mould
Eukaryotic
Haploid

Question 4

Explain the experiments conducted by George Beadle and Edward Tatum

Answer 4

1. Found number of loci where mutations causes arginine autotrophy. They identified 3x genes on 3x different chromosomes
2. Studied compounds that would enable the auxotrophs to grow

Question 5

What compounds allowed the auxotrophs to grow

Answer 5

1. Ornithine
2. Citrulline
3. Arginine

Question 6

What compounds did Arg - 1 grow under?

Answer 6

Ornithinine, Citrulline, and Arginine

Question 7

What compounds did Arg - 2 grow under?

Answer 7

Citrulline and Arginine, not Ornithine

Question 8

What compounds did Arg - 3 grow under?

Answer 8

Arginine, not Ornithine or Citrulline

Question 9

What hypothesis was formed from this, explain

Answer 9

The basis of the one-gene-one-enzyme hypothesis

Hypothesises that each gene in an organism corresponds to a single enzyme, vice versa

Question 10

What does the one-gene-one-enzyme hypothesis apply to?

Answer 10

Proteins and enzymes

Question 11

What is the classical view of mutations?

Answer 11

Heritable change in a gene resulting in a phenotypic change

Question 12

What is the modern view of mutations?

Answer 12

Heritable change to the sequence of a DNA molecule