Lesson 8 Definitions Flashcards
DNA
polymer made from repeating nucleotide units
Nucleotides
made of a nucleobase, a deoxyribose sugar, and a phosphate group
Hydrogen bonds
link nucleobase pairs together: adenine pairs with thymine, cytosine pairs with guanine
codon
nucleotide triplets are “code words” for amino acids, genes contain instructions for making proteins
PCR
(polymerase chain reaction) l
gene inversion
order of a particular group of genes is reversed
gene duplication
group of genes is duplicated
gene translocation
information from one of two homologous chromosomes breaks and binds to the other, most likely to be lethal
nucleotide deletion
removal of nucleotide causes remainder of sequence to be out of place
nucleotide insertion
addition of nucleotide causes remainder of sequence to be out of place (also called frameshift mutation)
nucleotide inversion
portion of nucleotide sequence is reversed, not as lethal as insertion or deletion
nucleotide substitution
replacement of a nucleotide. Not as harmful as insertion/deletion; cause of sickle cell anemia, antibiotic resistance in some bacteria
spontaneous mutation
a mutation occurring in the absence of mutagens, usually due to errors in the normal functioning of cellular enzymes.
induced mutation
a mutation caused by mutagens, such as chemicals, radiation, or viral infections
neutral mutation
majority of mutations, neither harmful or beneficial
positive selection
(Darwinian selection)
nucleobase
nitrogen-containing biological compounds that form nucleosides, which, in turn, are components of nucleotides, with all of these monomers constituting the basic building blocks of nucleic acids
RNA
ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information
anticodon
a sequence of three nucleotides forming a unit of genetic code in a transfer RNA molecule, corresponding to a complementary codon in messenger RNA
DNA replication
the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritance
helicase
enzymes that bind and may even remodel nucleic acid or nucleic acid protein complexes
DNA binding protein
proteins that have DNA-binding domains and thus have a specific or general affinity for single- or double-stranded DNA
DNA polymerase
a member of a family of enzymes that catalyze the synthesis of DNA molecules from nucleoside triphosphates, the molecular precursors of DNA. These enzymes are essential for DNA replication and usually work in groups to create two identical DNA duplexes from a single original DNA duplex.
mutagen
an agent, such as radiation or a chemical substance, which causes genetic mutation.
transcription factor
a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence
RNA polymerase
a multi-unit enzyme that synthesizes RNA molecules from a template of DNA through transcription
tRNA
transfer RNA
mRNA
messenger RNA
ribosomal subunit
required for translation
protein translocation
after the protein is formed, it is transported to other parts of the cell
translocon
complex of proteins associated with transport of proteins across membranes
signal sequence
short amino acid sequence on some proteins that acts as a “zip code” for the target organelle
DNA ligase
attaches Okazaki fragments together
topoisomerase
unwinds DNA
