Mutagens
permanent changes to the nucleotide sequence of a cell's DNA or RNA
What are mutations?
A change in a single nucleotide in a DNA sequence.
What is a point mutation?
A mutation occurs in normal body cells and is not passed on to offspring.
What is a somatic mutation?
A mutation that results in a different mRNA codon but codes for the same amino acid, causing no change in the phenotype.
What is a silent mutation?
The ultimate source of new alleles and genetic change.
What are mutations?
A chemical or energy form, such as radiation, that promotes changes in genetic material
What is a mutagen?
An insertion or deletion of a nucleotide that changes the reading frame of codons.
What is a frameshift mutation?
A mutation can be passed on to all cells in an offspring.
What is a germ-line mutation?
A mutation that is a base substitution that changes one amino acid in the polypeptide sequence.
What is a missense mutation?
The movement of genes between populations.
What is gene flow?
A type of mutagen includes X-rays, gamma rays, and UV light.
What is electromagnetic radiation?
A type of mutation that results in a change to the DNA structure that is large enough to be observed through karyotype comparison.
What is a chromosomal mutation?
Somatic mutations do not directly change the allele frequency in the gene pool, while germ-line mutations have the potential to change allele frequency in the gene pool.
What is a major difference in the effect of somatic versus germ-line mutations on the gene pool?
A length of the DNA is composed of genes that act as templates for forming polypeptides
What are 'coding' sections of DNA?
Meiosis causes genetic variation through random segregation of chromosomes and crossing over.
How does meiosis cause genetic variation?
Physical, chemical, and naturally occurring mutagens.
What are the three main classes of mutagens?
Deletion, duplication, inversion, and translocation.
What are the four main types of chromosomal rearrangements?
Gametes (sperm and egg cells) that carry DNA and genes to the next generation.
What are germ-line cells?
A mutation occurs in a promoter sequence which prevents the transcription of a polypeptide.
How can a mutation in a 'non-coding' DNA segment affect polypeptide synthesis?
Random, chance effects on allele frequency, which are more significant in small populations.
What is genetic drift?
Naturally occurring mutagen produced by molds from contaminated food and is converted into a reactive mutagen by the liver.
What is aflatoxin?
A mutation that results in a premature stop codon, terminating polypeptide synthesis and making the polypeptide non-functional.
What is a nonsense mutation?
Somatic mutations that are carried in the daughter cells of the original mutant cell, and depending on where they occur, they may lead to tumor growth.
How can a somatic mutation in an individual lead to a disease like cancer?
What disease is an example of a mutation in a 'non-coding' DNA segment, where more than 40 short tandem repeats of the base sequence CAG results in the disease.
What is Huntington's disease?
Mutation, genetic drift, and gene flow.
What are the three main factors that have a significant effect on the gene pool of a small population?