Lecture 1 - Nucleic Acids (Part I)

Molecular Biology

The study of biological phenomena at the molecular level, focusing on DNA, RNA, proteins, and other macromolecules involved in genetic information and cell function.

DNA

Deoxyribonucleic acid, a molecule that stores genetic information controlling cellular processes.

RNA

Ribonucleic acid, a molecule involved in the transfer of genetic information for the production of proteins.

Nucleic Acids

Polymers of nucleotides, including DNA and RNA, responsible for storing and transferring genetic information.

Nucleotides

Building blocks of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base.

DNA Primary Structure

Describes the sequence of nucleotides in each DNA strand, including dAMP, dGMP, dCMP, and dTMP.

DNA Secondary Structure

Refers to the double helix structure of DNA, with two antiparallel strands held together by complementary base pairing.

Complementary Base Pairing

Specific hydrogen bonding between adenine-thymine and guanine-cytosine base pairs in DNA.

Base Stacking

Stacking of base pairs in the DNA helix through Van der Waals forces and hydrophobic interactions for stability.

Double Helix

The spiral staircase-like structure of DNA, with 10.4 base pairs per turn and specific dimensions.

B-Form of DNA

The most common physiological form of DNA proposed by Watson and Crick, with specific structural characteristics.

Z-Form of DNA

A left-handed double helical DNA form with alternating cytosine and guanine bases, longer and thinner than B-DNA.

DNA Tertiary Structures

The higher-order structures of DNA, which can be linear or circular, and undergo supercoiling for packaging.

Supercoiling

The process of coiling DNA more tightly (positive supercoils) or less tightly (negative supercoils), influencing DNA functions.

Plasmids

Small, circular extrachromosomal DNA molecules found in bacteria, carrying genes that confer antibiotic resistance.

Mitochondrial DNA (mtDNA)

DNA found in the mitochondria, making up 0.3 to 1% of total cellular DNA, responsible for controlling the synthesis of rRNA, tRNA, and proteins involved in oxidative phosphorylation.

Denaturation of DNA

The process of heating DNA to break hydrogen bonds and separate the two strands, accompanied by increased UV light absorption and decreased viscosity.

Melting temperature (Tm)

The temperature at which 50% of DNA loses its helical form during denaturation.

Renaturation or Reannealing

The process of cooling denatured DNA to allow the reformation of the double helix structure.