Deck 9 Flashcards
Helicase
An enzyme that untwists the double helix of DNA at the replication forks.
Gene
DNA segments that serve as the key functional units in hereditary transmission.
silent mutation
A mutation that changes a single nucleotide, but does not change the amino acid created.
missense mutation
subsitution of wrong nucleotide into DNA; still produces a protein
nonsense mutation
subsitution of wrong nucleotide into DNA that produces an early stop codon
frameshift mutation
mutation that involves the insertion or deletion of a nucleotide in the DNA sequence
Mutation
A rare change in the DNA of a gene, ultimately creating genetic diversity.
gene expression
process by which a gene produces its product and the product carries out its function
Central Dogma of Molecular Biology
DNA –> RNA –> Protein
Transcription
DNA to RNA
RNA polymerase
Enzyme that links together the growing chain of ribonucleotides during transcription.
Promoter
Specific region of a gene where RNA polymerase can bind and begin transcription
terminator
In prokaryotes, a special sequence of nucleotides in DNA that marks the end of a gene.
Codon
The three-base sequence of nucleotides in mRNA
stop codon
codon that signals to ribosomes to stop translation
start codon
codon that signals to ribosomes to begin translation; codes for the first amino acid in a protein
Anticodon
group of three bases on a tRNA molecule that are complementary to an mRNA codon
mRNA (messenger RNA)
The form of RNA which is created as a blueprint from DNA; carries instructions for making a protein
tRNA (transfer RNA)
The form of RNA that carries each amino acid to the ribsome to form the polypeptide chain (protein)
rRNA (ribosomal RNA)
type of RNA that makes up the major part of ribosomes
Species
A group of similar organisms that can breed and produce fertile offspring.
Population
A group of individuals that belong to the same species and live in the same area
gene pool
Combined genetic information of all the members of a particular population
evolutionary fitness
success in passing genes to the next generation
adaptive trait
a heritable trait that enhances an individuals fitness; an evolutionary adaption
sexual selection
when individuals select mates based on heritable traits
artificial selection
selective breeding of plants and animals to promote the occurrence of desirable traits in offspring
gene flow (migration)
movement of alleles from one population to another
genetic drift
random change in allele frequencies that occurs in small populations
bottleneck effect
a reduction in the genetic diversity of a population caused by a reduction in its size
