DNA, Genes and Protein Synthesis

Nucleotide

A building block of nucleic acids, made of a sugar, a phosphate, and a base.

Pentose sugar

A five-carbon sugar molecule, either ribose (in RNA) or deoxyribose (in DNA).

Pyrimidines

Nitrogenous bases with a single-ringed structure, including Cytosine, Thymine, and Uracil.

Purines

Nitrogenous bases with a double-ringed structure, including Adenine and Guanine.

ATP (Adenosine Triphosphate)

The energy carrier molecule in cells, consisting of adenine, ribose sugar, and three phosphate groups.

Energy

The ability to work, existing in various forms such as chemical, light, and mechanical energy.

Metabolism

All the chemical reactions taking place in an organism.

Photophosphorylation

The synthesis of ATP occurring during photosynthesis.

Oxidative phosphorylation

ATP synthesis occurring in mitochondria during the transfer of electrons.

Substrate-level phosphorylation

ATP synthesis that occurs through the direct transfer of phosphate groups from donors to ADP.

Gene

A section of DNA that contains coded information for making polypeptides and functional RNA.

Triplet

A sequence of three nucleotide bases in DNA or RNA that codes for a specific amino acid.

mRNA (Messenger RNA)

Single-stranded RNA that carries instructions from DNA for protein synthesis.

tRNA (Transfer RNA)

Clover-shaped RNA that brings amino acids to the ribosome for protein synthesis.

Transcription

The process by which DNA is copied into mRNA.

Translation

The process by which mRNA is decoded into a polypeptide chain (protein).

Mutation

A change in the quantity or structure of DNA, which can affect genetic information.

Silent mutation

A mutation that does not result in a change to the primary sequence of a polypeptide.

Substitution mutation

A type of mutation where one nucleotide is replaced by another.

Deletion mutation

A mutation where a nucleotide is lost, potentially causing a frameshift.

Insertion mutation

A mutation where an additional nucleotide is added to the DNA sequence.

Polyploidy

A condition in which a cell has more than two paired (homologous) sets of chromosomes.

Non-disjunction

The failure of homologous chromosomes to separate properly during meiosis, leading to gametes with abnormal chromosome numbers.