Question

1. which nitrogen bases pair together in dna? 5. which base is found only in rna? 6. what is the \sugar - phosphate backbone\ in a nucleic acid? 7. why is dna referred to as the \code of life\? 8. how does rna contribute to protein synthesis? 9. explain how genetic information is inherited through dna.

Explanation:

1. In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G) through hydrogen - bonding.
2. Uracil (U) is the base found only in RNA. It replaces thymine in RNA.
3. The sugar - phosphate backbone in a nucleic acid is formed by alternating sugar (deoxyribose in DNA, ribose in RNA) and phosphate groups. Phosphodiester bonds link the 3' - hydroxyl group of one sugar to the 5' - phosphate group of the next sugar.
4. DNA is referred to as the "code of life" because it contains the genetic instructions for the development, functioning, growth, and reproduction of all known living organisms and many viruses. The sequence of its nitrogen - bases encodes information for making proteins and other cellular components.
5. RNA contributes to protein synthesis in several ways. Messenger RNA (mRNA) carries the genetic code from DNA to the ribosomes. Transfer RNA (tRNA) brings amino acids to the ribosomes according to the codons on the mRNA. Ribosomal RNA (rRNA) is a component of ribosomes, which are the sites of protein synthesis.
6. Genetic information is inherited through DNA as DNA replicates before cell division. Each new cell receives a copy of the DNA. During sexual reproduction, gametes (sperm and egg) carry half of the DNA from each parent, and when fertilization occurs, the resulting zygote has a complete set of DNA, combining genetic information from both parents.

Answer:

1. Adenine (A) pairs with thymine (T), cytosine (C) pairs with guanine (G).
2. Uracil (U).
3. Alternating sugar (deoxyribose in DNA, ribose in RNA) and phosphate groups linked by phosphodiester bonds.
4. It contains genetic instructions for life processes.
5. mRNA carries the code, tRNA brings amino - acids, rRNA is part of ribosomes.
6. DNA replicates before cell division and is combined during sexual reproduction.