Question

1. eight components present in nucleic acids are listed in the box. components of nucleic acids 1. phosphate 2. ribose sugar 3. deoxyribose sugar 4. uracil 5. thymine 6. adenine 7. guanine 8. cytosine which components pair with adenine in a section of double - stranded dna? a. 1, 3, 5 and 6 only b. 3 and 5 only c. 2 and 4 only d. 3, 4, 7 and 8 only 4. characteristics such as a widows peak or attached earlobes are determined by the genetic code. which components of dna are referred to as the genetic code? a. phosphate groups b. nitrogenous bases c. deoxyribose sugars d. hydrogen bonds 5. the diagram shows important structures found in a cell. two structures, w and z, are labelled. which statement best describes structure w and structure z? a. structure w is a gene and structure z is a chromosome. b. structure w is a chromosome and structure z is a gene. c. structure w is an amino acid and structure z is a nucleic acid. d. structure w is a nucleic acid and structure z is an amino acid. 6. the sequence of nitrogenous bases in dna varies widely. the sequence of the bases in dna is most important for which of the following? a. providing the instructions for the traits of an organism b. preventing mutations from occurring during dna replication c. allowing the dna to have the shape necessary for replication d. helping form the sugar - phosphate backbone of dna molecules

Explanation:

1. In DNA, adenine (A) pairs with thymine (T). Deoxyribose sugar and phosphate are part of the DNA backbone, and uracil is in RNA not DNA. So the components that pair with adenine in double - stranded DNA are thymine (5), deoxyribose sugar (3) which is part of the nucleotide structure that pairs with adenine.
2. The genetic code is determined by the sequence of nitrogenous bases in DNA. Phosphate groups, deoxyribose sugars and hydrogen bonds are important for the structure of DNA but do not constitute the genetic code.
3. Chromosomes are made of DNA and proteins. Genes are segments of DNA on chromosomes. So if W is a part of the coiled structure and Z is the long - chain molecule, W is a chromosome and Z is a gene.
4. The sequence of nitrogenous bases in DNA is most important for providing the instructions for the traits of an organism as it codes for proteins which determine traits.

Answer:

1. B. 3 and 5 only
2. B. Nitrogenous bases
3. B. Structure W is a chromosome and Structure Z is a gene.
4. A. Providing the instructions for the traits of an organism