A1.2 (Nucleic Acids)

DNA

a molecule that carries the genetic instructions for all known living organisms and many viruses. It is structured as a double helix, a twisted ladder-like shape, and is composed of nucleotides that incluse deoxyrobose sugar

RNA

a molecule that plays a crucial role in transmitting genetic information, directing protein synthesis, and regulating cellular processes. It is a single-stranded nucleic acid, composed of nucleotides containing ribose sugar

Nucleotides

the fundamental building block of nucleic acids like DNA and RNA. It consists of three main components: a pentose sugar, a phosphate group, and a nitrogenous base.

Phosphate

an inorganic molecule composed of a phosphorus atom bonded to four oxygen atoms. It plays a crucial role in various biological processes, including DNA structure.

Deoxyribose

a pentose sugar that is a fundamental component of DNA. It has one less oxygen than ribose

Ribose

a pentose sugar that is a fundamental component of RNA. It also has many other uses as a monosaccharide.

Nitrogenous base

a nitrogen-containing organic compound that forms part of nucleotides. There are 5 types: Adenine, Thymine, Cytosine, Guanine, & Uracil.

Genetic code

the set of rules that defines how the four nucleotide bases in DNA or RNA are translated into the 20 standard amino acids that make up proteins

Polymer

a large molecule, or macromolecule, composed of many smaller, repeating units called monomers

Condensation Reaction

a process where two molecules combine to form a larger molecule, with the release of water

Complementary base pairs

the specific pairings of nitrogenous bases in DNA and RNA, where adenine (A) always pairs with thymine (T) in DNA, and with uracil (U) in RNA, while guanine (G) always pairs with cytosine (C).

Polynucleotide

a biopolymer composed of nucleotide monomers linked together by covalent bonds, forming a chain

Antiparallel

the arrangement of two strands, such as those in a DNA double helix, where they run parallel to each other but in opposite directions

DNA Replication

the biological process of producing two identical copies of a single DNA molecule

Gene expression

the process by which the information encoded in a gene is turned into a functional molecule eg. protein

Virus

an infectious agent that replicates only inside the living cells of an organism.

Homeostasis

the body's ability to maintain a stable internal environment despite external changes

Metabolism

the sum of all enzyme-controlled chemical reactions that occur within a living organism to sustain life

Purines

a type of nitrogenous base. In DNA and RNA they are adenine and guanine. It is an organic compound consisting of two fused rings that contain nitrogen.

Pyrimidines

a type of nitrogenous base. In DNA and RNA they are cytosine, thymine & uracil. It is an organic compound consisting of a single-ring structure that contains nitrogen.

Nucleosome

a structure that consists of DNA wrapped twice around 8 histone proteins. It helps with DNA organisation & supercoiling.

Histones

basic proteins that are the primary structural components of chromosomes and are involved in packaging DNA in the nucleus

Tetranucleotide hypothesis

proposed by Phoebus Levene in 1909, suggested that DNA structure was based on repeating sequences of four nucleotides, with each nucleotide present in approximately equal amounts

Radioisotopes

radioactive isotopes of an element, meaning they are unstable and undergo radioactive decay, emitting radiation. This is able to be visualised by certain technologies.

5’ to 3’

refers to the directionality of DNA and RNA strands. The 5' end is the phosphate end of the sugar-phosphate backbone, while the 3' end is the hydroxyl end.

Chargaff’s rule

in DNA, the number of adenine (A) bases is equal to the number of thymine (T) bases, and the number of guanine (G) bases is equal to the number of cytosine (C) bases. These ratios will be identical within a specied, but differ between them.

Induction

making a general conclusion based on specific observations or instances. It's often called "bottom-up" reasoning because it starts with specific details and moves towards a broader generalization

Falsification

To perform a test showing that a particular claim or scientific idea is false