(20 points) describe the structures of proteins and nucleic acids, and then explain the relationship between these two molecules within a cell.

Proteins are polymers, and they contain C, O, H, N, and sometimes S, depending on the R-group of the amino acid. The monomer of proteins are Amino acids. Amino acids have two functional groups, carboxyl and amine groups. The other one is the R-group, and there are 20 possible types of them. Proteins are important, and they can be used as biocatalysts, vital in cell membrane, etc.

There are two types of nucleic acids, DNA and RNA. DNA, or deoxyribonucleic acid, has a pentose sugar, deoxyribose which is covalently connected to a phosphorous (connected through phosphdiester bond), and a nitrogenous base. There are four possible nitrogenous base, and they can be purines (double ringed, A and G ) or pyrimidines (single ringed, C, T, and U in RNA). DNA has a phosphorus and carboxyl group. The monomer for any nucleic acid is called a nucleotide.

RNA has a few major differences from DNA. RNA's pyrimidine is uracil instead of thymine. Also, the pentose sugar for RNA is simply ribose. This means that there is a -OH in the pentose sugar.

Proteins and Nucleic acids work side-by-side in DNA replication. They also have many other uses too.

the correct answer is option b

behavioral response need communication and thus co-ordination at several levels such as interaction among cells, organ system and the entire organism.

behavioral response produces both internal and environmental stimulus.

the correct option is option d