There are called Amino Acids.
Answer:
b. Even though the DNA sequence changed, the sequence still codes for the same amino acid, so no change in phenotype will occur.
Explanation:
There is redundancy in the genetic code. That means that different codons can code for the same amino acids, so some mutations do not change the amino acid sequence of the protein.
Here, the amino acid is unchanged with the mutation.
If the amino acid sequence of the protein is the same, then the protein is not changed, so there will be no change in the phenotype
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.
