Question

there are about 20 different kinds of amino acids that make up proteins. these amino acids consist of five separate parts. the first is a central carbon atom. second is a carboxyl group (-cooh). third is an amino group (-nh2). fourth is a hydrogen. the fifth group is a variable r group. the only difference in the 20 kinds of amino acids is the r group. some r groups are very small, others are large, and even others form chains and rings. the sequence and shapes of the r groups control the shape and function of the protein. nine amino acids are not synthesized by mammals and are therefore dietary essential or indispensable nutrients. these are commonly called the essential amino acids. 14. what part of the amino acid varies from one amino acid to another and determines the shape and function of the protein? 15. if nine essential amino acids are not made by the human body, then how do you get them? nucleic acids nucleic acids are biomolecules that involve the genetic material dna and rna. the building block of nucleic acids is the nucleotide. all nucleic acids are formed from a series of these nucleotides. dna is the blueprint of life because it contains instructions on how to make proteins in the body. each individuals dna is unique, which means that each individual has a unique set of proteins. that is why each of us looks and behaves differently. rna is made by copying dna. dna is found in the nucleus of cells. because dna cant leave the cells nucleus, and because proteins are constructed outside of the nucleus of the cell, rna is necessary to carry the instructions from dna to outside of the nucleus of the cell where proteins are made. 16. what are the two types of nucleic acids? 17. how does the role of rna differ from that of dna?

Explanation:

1. The text states that the 'R' group varies among amino - acids and controls protein shape and function.
2. Since the body doesn't make essential amino - acids, they must be obtained from food.
3. The text clearly mentions DNA and RNA as the two types of nucleic acids.
4. DNA contains instructions for making proteins and is in the nucleus, while RNA copies DNA and carries instructions from the nucleus to where proteins are made.

Answer:

1. The "R" group.
2. Through diet (by eating foods that contain them).
3. DNA and RNA.
4. DNA is the blueprint of life in the cell nucleus containing instructions for making proteins. RNA is made by copying DNA and carries these instructions from the nucleus to outside the nucleus where proteins are made.