CH16

Question 0

What was the experiment with Hershey and chase?

Answer 0

The experiment gave evidence tht DNA was the genetic material from virus’ tht infect bacteria. Bacteriophages or phages.
They found out tht the phage DNA entered the host cells but the phage protein did not.
They concluded tht DNA injected by the phage must b the molecule carrying the genetic info tht makes the cell produce more new viral DNA

Question 1

What was the transformation experiments of Griffith and subsequent work of avery?

Answer 1

He had 2 strains of bacterium, one disease causing the other harmless.
When he killed the pathogenic bacteria with heat thenmixed the cell remains with the bacteria some of the cells became pathogenic.
Griffiths called this transformation (avery and his team determined transformation was DNA)

Question 2

Chargaff’s did chargaff’s work find?

Answer 2

Chargaff found tht A =T and C = G
CHargaff’s rule: 1) the base composition of DNA varies between species and 2) for each species the % of A and T are = and C and G r =.

Question 3

define transformation

Answer 3

a change in genotype and phenotype due to the assimilation of external DNA

Question 4

Define Bacteriophage (phage)

Answer 4

Means bacteria eater

Question 5

Define pyrimidine

Answer 5

One or two types of nitrogenous bases found in nucleotides, characterized by a six-membrane ring. Cytosine (C) , Thymine (T), Uracil (U) are pyrimidines

Question 6

Define Purine

Answer 6

One or two types of nitrogenous bases found in nucleotides , characterized by six- membered ring fused to a five-membered ring
Adenine (A), Guanine(G) are purines