Answer:
As DNA contain phosphorus in its structure in large amount, therefore, Harshey and Chase labeled DNA with radioactive phosphorus and because protein contains some amino acids which have sulfur so they labeled T2 bacteriophage protein with sulfur.
So after that they infected E.coli bacteria with radioactively labeled phages and after centrifugation, they have found that pellet which contains cells is showing the presence of radioactive phosphorus and supernatant which have T2 phage capsid protein showing the presence of radioactive sulfur.
Therefore by labeling viral protein and viral DNA they found that DNA is the genetic material not protein.
Answer:
B. Because weather is a complex interaction among many different variables that are constantly changing
Explanation:
Answer:
Watson and Crick proposed the double helical model of DNA.
Explanation:
- This model says that DNA exist as double helix. It has two polynucelotide strands running in opposite direction i.e the strands are anti-parallel.
- Each polynucleotide strand is made up of several nucleotide liknked together by phophodiester bonds.
- The two strands are not coiled upon each other but the double strand is coiled upon itself around a common axis like the spiral stair case. Here base pairs forms the stairs and backbone of two strands form railing. Back bone contains sugar and phosphate.
- The base pairing is specific, adenine always pairs with thymine and guanine always pairs with cytosine. Thus if we see any base pair, it consists of one purine and one pyrimidine.
- The two strands of DNA thus show complementary base pairing.
- The strands are held together because of hydrogen bonding between the bases in opposite strand.
- One full helical turn involves ten base pairs and the base pairs are stacked 3.4 A apart.
- This form is called as B-form of DNA.