TEKS B.6(A) - DNA Structure

Eight components present in nucleic acid are listed in the box.

Which components bond with adenine in a section of double stranded DNA?

• 1, 3, 5, & 6 only

• 3 & 5 only

• 2 & 4 only

• 3, 4, 7, & 8 only

A segment of a DNA strand is shown.

Which of these is the correct complementary DNA strand for the segment shown?

• AGGTCAGGT

• ACCUGAGGU

• TGGACTGGA

• TCCAGTCCA

Which part of a DNA molecule is responsible for the direct coding of specific traits in an organism?

• The number of hydrogen bonds that hold the strand of DNA together.

• The number of carbons in the DNA molecule.

• The sequence of nucleotides bases in the DNA molecule.

• The sequences of phosphates along each DNA strand.

Differences in traits such as hair texture are determined by differences in -

(a)  

• the location of sugar groups in DNA
• the sequence of nucleotides in DNA
• the number of nitrogenous bases in DNA
• the molecules attached to the phosphate in DNA

Nitrogenous bases are located on both strands of the DNA double helix. What is the significance of the nitrogenous bases?

• The number of adenines and cytosines determines the type of RNA that will be produced

• The order of nitrogenous bases determine the order of amino acids in the proteins synthesized

• The amount of thymine and guanine in the DNA molecules determines the length of the genes.

• The type of hydrogen bonding between the nitrogenous bases determines which amino acid will be added to the peptide chain.