Untitled Flashcards Set

Alkaptonuria

An autosomal recessive trait with altered metabolism of homogentisic acid due to lack of enzyme production.

Amino acid

One of the 20 subunits of proteins, each containing an amino group, a carboxyl group, and an R group.

Codon

Triplets of nucleotides in mRNA that encode information for a specific amino acid.

Stop codon

A codon in mRNA that signals the end of translation; specifically UAA, UAG, and UGA.

Start codon

The codon AUG in mRNA that signals the beginning of translation and codes for methionine.

pre-messenger RNA (pre-mRNA)

The transcript made from the DNA template that is processed to form messenger RNA.

Transcription

The transfer of genetic information from DNA to RNA.

Messenger RNA (mRNA)

A single-stranded copy of the nucleotide sequence in a gene.

Translation

The conversion of mRNA nucleotide sequence into the amino acid sequence of a protein.

Promoter

A regulatory region located at the beginning of a gene.

Introns

Transcribed DNA sequences that are removed during mRNA processing and not present in mature mRNA.

Exons

Transcribed DNA sequences that are retained and translated into the amino acid sequence of a protein.

Cap

A modified guanine nucleotide attached to the 5′ end of eukaryotic mRNA.

Poly-A tail

A series of adenine nucleotides added to the 3′ end of mRNA molecules.

R group

The side chain unique to each amino acid, which can be charged or neutral.

Amino group

A chemical group (NH2) found in amino acids and at one end of a polypeptide chain.

Carboxyl group

A chemical group (COOH) found in amino acids and at one end of a polypeptide chain.

Essential amino acids

Amino acids that cannot be synthesized by the body and must be included in the diet.

Polypeptide

A molecule made of amino acids joined together by peptide bonds.

N-terminus

The end of a polypeptide that has a free amino group.

C-terminus

The end of a polypeptide that has a free carboxyl group.

Ribosomes

Cytoplasmic particles that aid in protein production.

Ribosomal RNA (rRNA)

RNA molecules that form part of the ribosome.

Transfer RNA (tRNA)

A small RNA molecule that brings specific amino acids to the ribosome.

Anticodon

A group of 3 nucleotides in a tRNA that pairs with a codon in mRNA.

Initiation complex

Formed by mRNA, tRNA, and the small ribosome subunit; the first step in translation.

Peptide bond

A covalent bond linking the carboxyl group of one amino acid to the amino group of another.

Polysomes

mRNA molecules with several ribosomes attached for translation.

Chaperone

A protein that assists in folding polypeptides into functional proteins.

Proteome

The complete set of proteins present in a cell at a specific time.

Primary structure

The amino acid sequence of a polypeptide chain.

Secondary structure

The pleated or helical structure in a protein created by bonds between amino acids.

Tertiary structure

The three-dimensional shape of a protein, formed by folding.

Quaternary structure

The structure formed by the interaction of multiple polypeptide chains.

Prion

A misfolded protein that causes infectious diseases.

Mad-cow disease

A prion disease in cattle, also known as bovine spongiform encephalopathy (BSE).

Chromatin remodeling

Chemical changes to DNA and histones that activate and inactivate gene expression.

RNA interference (RNAi)

A mechanism that regulates gene expression by controlling mRNA levels.

Substrate

The specific chemical compound acted on by an enzyme.

Product

The chemical compound produced as a result of enzymatic action.

Metabolism

The sum of all biochemical reactions that produce and utilize energy in cells.

Inborn error of metabolism

Genetic traits resulting from alterations in biochemical pathways.

Phenylketonuria (PKU)

An autosomal recessive disorder of amino acid metabolism that can cause intellectual disability.

Galactosemia

An inability to metabolize galactose, leading to accumulation and potential intellectual disability.

Hemoglobin variants

Alpha and beta globins with different amino acid sequences.

Thalassemias

Disorders caused by imbalances in alpha and beta globin production.

Pharmacogenetics

The study of genetic differences that affect drug response.

Ecogenetics

The study of genetic traits related to responses to environmental substances.

Mutation rate

The frequency of events producing mutated alleles per locus per generation.

Trinucleotide repeats

Mutations associated with the expansion of nucleotide triplets near a gene.

Mutagens

Agents that induce mutations in DNA.

Tautomeric shift

A reversible change in structure due to a shift in hydrogen atom location.

Radiation

The emission of energy as electromagnetic waves or particles.

Background radiation

Environmental radiation contributing to overall exposure.

Rem

A unit for measuring radiation exposure and its effects in humans.

Millirem

A measurement of radiation dose equal to 1000 millirems.

Base analogs

Chemicals similar to normal bases in DNA and RNA but differ structurally.

Nucleotide substitutions

Mutations that replace nucleotides in DNA with other nucleotides.

Frameshift mutations

Mutations where bases are added or removed, shifting the codon reading frame.

Missense mutations

Mutations causing substitution of one amino acid for another in a protein.

Sense mutations

Mutations changing a termination codon to one that codes for an amino acid.

Nonsense mutations

Mutations changing an amino acid codon to a termination codon.

Allelic expansion

Increase in gene size from more trinucleotide repeat sequences.

Epigenetics

The study of chemical modifications of DNA and associated proteins affecting gene expression.

Epigenetic trait

A phenotype produced by epigenetic changes to DNA.

Epigenome

The complete set of epigenetic modifications in a cell.

Methylation

The addition of a methyl group to a DNA base or protein.

Genetic imprinting

Selective expression of either the maternal or paternal allele of a gene.