Nucleic acids (DNA and RNA)

"DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid) are nucleic acids first discovered in the nuclei of cells.

They are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen and phosphorus.

DNA – Deoxyribonucleic Acid

RNA – Ribonucleic Acid

NUCLEIC - reffering to the nucleus

NUCLEI (pl of NUCLEUS)

Nucleic acids consist of repeating building blocks called nucleotides. Each nucleotide comprises one of four different nitrogenous bases, a five-carbon sugar (in DNA deoxyribose and in RNA ribose) and a phosphate group.

The four nitrogenous bases are adenine (A), thymine (T), cytosine (C) and guanine (G). In RNA thymine (T) is replaced by uracile (U).

Adenine always pairs with thymine (or uracil in RNA) and cytosine always pairs with guanine. Paired bases are held together by hydrogen bonds.

NITROGENOUS - containing nitrogen

A BASE - a chemical that dissolves in water and combines with an acid to create a salt

A FIVE-CARBON SUGAR = DEOXYRIBOSE, RIBOSE

A PHOSPHATE - a chemical compound that contains phosphorus

TO PAIR WITH - to go together

A (CHEMICAL) BOND - the force holding atoms together in a molecule

DNA is a double helix, i.e. “a ladder“ that is comprised of two upright strands twisted and linked with each other with crossbars.

DNA was first discovered by James Watson and Francis Crick in 1953 and it is a primary component of a gene. Around 1000 rungs of DNA create a gene and humans have about 30,000 genes. Genes determine which traits we inherit and they control all the activities that take place in our cells throughout a lifetime.

A HELIX - a curve that goes around a central tube or cone shape in the form of a spiral

UPRIGHT - straight up, vertical

A STRAND - a thin thread twisted around sth

A CROSSBAR - a horizontal bar

A RUNG - any of the short bars that form the steps of a ladder

Any change that occurs in the sequence of nitrogenous bases of a gene is called a mutation.

RNA is copied from DNA and it is single and not double-stranded. Cells contain three different kinds of RNA: messenger RNA, ribosomal RNA and transfer RNA. Each has a specific role to perform in carrying out the instructions encoded in DNA for protein synthesis."

ENCODED - converted into a code

Reference: Tortora Gerard J., Derrickson Bryan “Essentials of Anatomy and Physiology” (2013)