genetics- mutations Flashcards
Variety exists within the same species due to:
variations in genes
Mutations are:
permanent changes to the nucleotide sequence of DNA
changes in dna can be:
a change in a single base pair, multiple bases or entire sections of chromosomes
mutations can create:
new alleles and therefore new traits
DNA Replication:
copying of dna during cell divisions results in mistakes
most errors are corrected but humans pass on about 100-200 mutations per generation
Mutagens cause:
damage to DNA
increasing the likelihood of mutations
Examples of mutagens are:
ionizing radiation such as uv lights and xrays strid electrons from dna, breaking bonds
chemicals like benzene and heavy metals can bind to the dna molecule and disrupt the structure
some viruses insert themselves into the dna strand, disrupting the nucleotide sequence
define: carcinogen
a substance or agent that causes cancer
some mutagens are carcinogenic such as uv radiation, cigarette smoke
the 3 types of mutations are
substitution, insertion and deletion
substitution is when:
a single base(A,T,G,C,) is exchanged for another
this will change only one amino acid
insertion is when:
One or more bases are added to the nucleotide sequence
the insertions moves the subsequent nucleotides over, changing everything after the mutation
deletion is when:
one or more of the bases are removed from the sequence, as with insertion, the frame shift changes everything after the mutation
Using genetic information from DNA we can assemble:
a protein using mRNA and the genetic code
3 mRNA bases =
codon which is specific for one amino acid
AUG is:
Start codon at the beginning of each protein sequence
The three stop or terminator codons are:
UAA, UAG, UGA
they are at the end of a gene and cause a releasing factor to let go of the protein
DNA to Protein:
Transcripted to become RNA then translated to form amino acids which for proteins
Three effects of mutatinos
positive, negative, neutral
Define: Positive mutation
any mutation that improves the function of a gene by causing it to create better protein
will give an organism an advantage over other members of its species
Define: Negative mutation
any mutation that decreases the function of a gene by creating a nonfunctional protein
negative mutations will place an organism at a disadvantage
Define: Neutral Mutation
any mutation that does not change the function of a protein
neutral mutations create proteins that are identical or have equivalent function
