Question

Consider the following statements:
(1) In proteins, only right handed helices are observed.
(2) In a polysaccharide chain, the right end is called the reducing end.
(3) B-DNA is generally coiled in left handed fashion.
Which of the statement(s) given above is/are incorrect?

• A. (3) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1) and (2) only

Answer 1

Answer: (A)

• In a polysaccharide chain, the right end is called the reducing end and the left end is called the non-reducing end.
• In proteins, only right handed helices are observed.
• The familiar Watson-Crick double helix of DNA, called B-DNA, winds in a right-handed direction. But like a screw, the helix can wind the other way: under certain conditions,
DNA adopts a left-handed form, called Z-DNA.