12-4, 12-5 Flashcards
Gene mutations
Mutations that produce changes in a single gene
Mutations
Changes in genetic material
Chromosomal mutations
Genes that produce changes in whole chromosomes
Point mutations
Gene mutations involving changes i. One or a few nucleotides
Occur at a single point in the DNA sequence
Substitutions
Insertions and deletions
Frame shift mutations
If a nucleotide is added or deleted it shifts the “reading frame” of the genetic message
- can alter a protein too much
- can change every amino acid that follows the point of each mutation
What can chromosomal mutations do
Can change the locations of genes on chromosomes and may even change the number of copies of some genes
Deletions
Loss of all or part of the chromosome
Duplication
Produce extra copies of parts of a chromosome
Inversions
Reverse the direction of parts of chromosomes
Translocation
When part of one chromosome breaks of and attaches to another
Polyploidy
Condition in which an organism has extra sets of chromosomes
Promoters
Binding sites for DNA polymerase
Regulatory sites
Places where other proteins binding directly to the DNA sequences at those sites can regulate transcription
Operon
group of genes that operate together
The lac genes
Turned off by depressors and turned on by the presence of lactose
Operator
Other region
Cells can
Turn their genes on and off as needed
Most eukaryotic genes
Are controlled individually and have regulatory sequences that are much more complex than the lac Operon
TATA box
Helps position RNA polymerase
Differentiation
They become specialized in structure and function
Hox genes
Control the differentiation of cells and tissues in the embryo
binding proteins bind directly to the DNA sequence and regulate transcription determining whether a gene is turned on or off
So yeah
LAC operon in E. coli regulates whether lactase has produced an enzyme needed for the breakdown of lactose
MHM
Operons are only in
Prokaryotes
