Biological Molecules: Proteins and Nucleic Acids

These flashcards cover key concepts about proteins, their structure, and nucleic acids, which are essential for understanding biological molecules.

What are the monomer subunits of proteins?

Amino acids.

What is the primary structure of a protein?

The linear sequence of amino acids, determined by the genetic code.

How are proteins held together?

By peptide bonds formed via dehydration synthesis between adjacent amino acids.

What is the difference between essential and non-essential amino acids?

Essential amino acids must be obtained from the diet, as the body cannot synthesize them, whereas non-essential amino acids can be synthesized by the body.

What defines the specific amino acid?

The unique R group, or side chain, attached to the central asymmetric carbon, which determines the amino acid's chemical properties and function.

What types of structures do proteins have?

Proteins have hierarchical structures: primary (amino acid sequence), secondary (local folding like alpha-helices and beta-sheets), tertiary (overall 3D shape), and some have quaternary (multiple polypeptide subunits).

What are the secondary structures of proteins formed by?

Hydrogen bonding between carbonyl (C=O) and amino (N-H) groups in the peptide backbone, leading to stable conformations like alpha-helices and beta-pleated sheets.

What is protein denaturation?

A process where a protein loses its specific three-dimensional structure and biological activity, often caused by disruptions in temperature, pH, or exposure to certain chemicals.

What are the two types of nucleic acids?

RNA (ribonucleic acid) and DNA (deoxyribonucleic acid), which are essential macromolecules for storing and transmitting genetic information.

What is the structure of a nucleotide?

A nucleotide is composed of a phosphate group, a 5-carbon sugar (ribose in RNA, deoxyribose in DNA), and a nitrogenous base. Nucleotides link via phosphodiester bonds to form nucleic acid polymers.

How are the strands of a DNA molecule arranged?

The strands are oppositely oriented (antiparallel), complementary to each other, and twisted into a double helix. Specific base pairing occurs where Adenine (A) pairs with Thymine (T), and Guanine (G) pairs with Cytosine (C).

What is the significance of the sequence of nitrogenous bases in DNA?

The precise sequence of nitrogenous bases on a DNA strand encodes the genetic information for building and maintaining an organism, and also dictates the sequence of the complementary strand.

What nitrogenous bases are found in RNA?

Adenine (A), Uracil (U), Cytosine (C), and Guanine (G). Uracil replaces Thymine found in DNA.

What nitrogenous bases are found in DNA?

Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).

What is the role of mRNA?

Messenger RNA (mRNA) carries genetic information copied from DNA in the nucleus to the ribosomes in the cytoplasm, where it serves as a template for protein synthesis.

How does the sequence of one DNA strand relate to the other?

If you know the sequence of one DNA strand, you can accurately deduce the sequence of the complementary strand due to consistent base pairing rules: Adenine (A) with Thymine (T), and Guanine (G) with Cytosine (C).