DNA - The Code of Life and RNA Flashcards

A comprehensive set of vocabulary flashcards covering the structure of DNA and RNA, protein synthesis, mutations, and DNA technology based on the lecture notes.

Nucleoplasm

A jelly-like liquid enclosed by the nuclear membrane within the nucleus.

Chromatin network

A mass of thread-like structures in the nucleus that coils and thickens into chromosomes during cell division.

Chromosomes

Long, thin, thread-like structures composed of DNA wrapped around proteins called histones; they are the carriers of genetic material.

Extranuclear DNA

DNA that occurs outside the nucleus, specifically in the mitochondria of plants and animals and the chloroplasts of plant cells.

Mitochondrial DNA (mtDNA)

DNA found in the mitochondria that is inherited only via the maternal line and used to trace maternal ancestry due to its relative lack of mutation.

Gene

A short segment of a DNA molecule that codes for a particular protein and controls an inherited characteristic.

Nucleic acids

Organic molecules, specifically DNA and RNA, that control protein synthesis by storing and transferring genetic information.

James Watson and Francis Crick

Scientists who formulated the double helix structure of DNA in 1953 using a three-dimensional model.

Rosalind Franklin

A scientist who took X-ray photographs of DNA in 1952 and surmised its helix shape, though she died before the Nobel Prize was awarded.

Friedrich Miescher

The scientist who identified DNA in 1874.

Erwin Chargaff

A scientist who determined in 1949 that there are equal numbers of Adenine and Thymine bases ($A = T$) and equal numbers of Guanine and Cytosine bases ($G = C$) in a DNA molecule.

Nucleotides

The monomers or building blocks of DNA or RNA, each consisting of a sugar molecule, a phosphate group, and a nitrogenous base.

Purine bases

Large nitrogenous bases known as Adenine (A) and Guanine (G).

Pyrimidine bases

Smaller nitrogenous bases known as Cytosine (C) and Thymine (T) in DNA, or Uracil (U) in RNA.

Hydrogen bonds

Weak bonds that join nitrogenous bases; two bonds form between Guanine and Cytosine, and three form between Guanine and Cytosine.

Non-coding DNA

Approximately $98\%$ of DNA that does not carry information to produce proteins; it is used in DNA fingerprinting and regulates gene expression.

DNA replication

The process taking place during Interphase where a DNA molecule duplicates to form two identical copies (replicas).

Chromatids

Two identical units formed when a chromosome duplicates during replication, held together by a centromere.

DNA polymerase

The specific enzyme responsible for joining free-floating nucleotides to build a complementary DNA strand during replication.

Messenger RNA (mRNA)

A single-stranded RNA formed in the nucleoplasm using DNA as a template; it carries the genetic code from the nucleus to the ribosomes.

Transfer RNA (tRNA)

A single-stranded RNA that folds into loops, contains an anticodon, and picks up specific amino acids in the cytoplasm to bring them to the ribosomes.

Transcription

The process where mRNA obtains the genetic code for protein synthesis from a DNA template in the nucleus.

Translation

The process where the code in the mRNA strand is used to form a specific sequence of amino acids to synthesize a protein at the ribosome.

Codon

A group of three nitrogenous bases on the mRNA molecule that codes for a particular amino acid.

Anticodon

A sequence of three exposed nitrogenous bases on a tRNA molecule that is complementary to an mRNA codon.

Base triplet

Three consecutive nitrogenous bases on a DNA strand that provide the code for a particular amino acid.

Mutation

Any change in the genetic composition of an organism, which can occur spontaneously or via mutagens.

Mutagens

Physical or chemical agents, such as X-rays, UV light, or toxic chemicals, that cause mutations.

Substitution mutation

A point mutation where one nitrogenous base is replaced by another, altering only one amino acid.

Frameshift mutation

A mutation caused by the deletion or insertion of nitrogenous bases (not in multiples of three), which alters all subsequent base triplets.

DNA profiling (DNA fingerprinting)

A process where a 'barcode' pattern is obtained from non-coding DNA to identify individuals or determine paternity.

Polymerase Chain Reaction (PCR)

A technology used to replicate and multiply small samples of DNA into millions of segments for testing in DNA fingerprinting.