DNA Structure and Gene Function

Practice vocabulary flashcards based on Lecture 9 regarding DNA structure, gene function, mutations, and viral agents.

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid polymer that stores genetic information, composed of a 5-carbon sugar (deoxyribose), phosphate, and nitrogenous bases in a double-helix structure.

Purines

A category of nucleotide monomers in DNA that includes adenine (A) and guanine (G).

Pyrimidines

A category of nucleotide monomers in DNA that includes cytosine (C) and thymine (T).

Coding strand

The strand of DNA that runs in the $5' \rightarrow 3'$ direction.

Template strand

The strand of DNA that runs in the $3' \rightarrow 5'$ direction and is used to build RNA during transcription.

Histones

Proteins around which DNA is wrapped to form chromosomes, influencing the accessibility of the DNA.

Autosomes

The chromosome pairs 1 through 22 in humans.

Sex chromosomes

The 23rd pair of chromosomes in humans, referred to as X and Y, which are not homologous.

Karyotype

An assessment or image identifying the number and size of chromosomes in a cell.

Gene

A sequence of DNA that contains specific instructions on how to build a protein.

Semi-conservative replication

The method of DNA replication where every resulting DNA molecule consists of one original (old) strand and one newly synthesized strand.

Mutation

A change to the original DNA sequence, which can be categorized as beneficial, harmful, or neutral.

Point mutation

A single change in a base pair that does not alter the overall length of the DNA sequence.

Insertion

A mutation involving the addition of one or more nucleotides to the DNA sequence.

Deletion

A mutation involving the removal of one or more nucleotides from the DNA sequence.

Central Dogma of Biology

The concept that genetic information flows from DNA to RNA through transcription, and from RNA to protein through translation.

Transcription

The process occurring in the nucleus, performed by RNA polymerase, that uses a DNA template to build RNA.

Translation

The process occurring in the cytoplasm or associated with the rough ER where ribosomes build proteins (polypeptides) from RNA.

mRNA (messenger RNA)

The type of RNA that carries protein-encoding information and is processed from pre-RNA via splicing.

tRNA (transfer RNA)

A type of RNA with an anticodon side for recognizing amino acids and an attachment site to bring the correct amino acid to the ribosome.

rRNA (ribosomal RNA)

A component of ribosomes consisting of two subunits that help initiate translation by binding with the mRNA cap-end.

Codon

A sequence of 3 nucleotides that corresponds to 1 specific amino acid; there are 64 possible combinations for 20 amino acids.

Promoters

Specific sites on the DNA where RNA polymerase attaches to initiate the process of transcription.

Operons

Segments of DNA where repressors or activators can bind to regulate gene expression.

Viruses (Virions)

Noncellular infectious agents consisting of genetic material contained within a protein coat.

Prion

A proteinaceous infectious particle that lacks nucleic acids and causes other proteins to misfold.

Viroid

A noncellular infectious agent that consists of genetic material but lacks the protein coat found in viruses.

Proteome

The collection of over 1,000,000 proteins that results from the original 20,000-25,000 genes in the genome due to alternative splicing and post-translational modifications.