Name: _______________________
Mutations and Gene Regulation

Mutations
o
Mutations are ____________________________________________________________
o
Gene mutations result from __________________ in a single gene. _________________
mutations involve changes in _________________ chromosomes.
o
Gene Mutations

Mutations that affect __________nucleotide are called point mutations because
they occur at a single ________________ in the DNA sequence.

Substitutions generally change one of the _______________ _______________
in a protein.

A much bigger change results from the _____________________ or
_______________________ of a nucleotide.

In these instances, the genetic code is still read in groups of __________
bases known as _______________, but the groupings are shifted for
every codon that follows.

Called “_________________________________” because the reading
frame of the genetic message has shifted.

Every ______________ ______________ that follows such a mutation is
affected, so the protein is ______________________ to perform its
normal ________________________.
o
Chromosomal Mutations

Involves changes in the ____________________ or _____________________ of
chromosomes

May change the ___________________ of genes on chromosomes and even the
_______________________ of copies of some genes.

Copy and Label Figure 12-20: Chromosomal mutations

Gene Regulation
o
Only a __________________ of the genes in a cell are expressed at any given time.
o
An _____________________ gene is one that is transcribed into ____________.
o
Certain DNA sequences are _______________________, binding sites for
____________________________________.
o
Some sequences are _____________ and ______________ signals for transcription.
o
Many proteins help _______________________ gene expression.
o
Gene Regulation: An Example

A group of genes that operate together is known as an __________________

The genes that must be expressed in E. coli for the bacterium to use the sugar
_______________ as a food, they are called the _____________ operon.

Lactose is made of the two simple sugars ____________________ and
_____________________

Lactose must be carried across the bacteria’s cell _______________________
and then the bacteria must ______________ the bond between glucose and
galactose in order to use it as food.

The bacterium needs to turn on these genes when _______________ is the only
food source.

Lac genes are turned off by _____________________ and turned on by the
presence of ______________________

RNA polymerase binds to the ___________________ and begins transcription.

However, if the _____________________ binds to the __________________(O)
region, RNA polymerase cannot bind to the promoter, and thus turns the
operon __________ by preventing the _____________________ of the genes.

When lactose is present, some of the _______________ molecules bind to the
repressor protein and cause it to ___________ off of the operator, freeing RNA
polymerase to bind to the ______________________ and transcribe the genes.
o
o
Eukaryotic Gene Regulation
 _____________________ are not usually found in eukaryotes.
 Most eukaryotic cells are controlled ____________________ and have
regulatory ______________________ that are much more _________________
than those of the lac operon.
 The ______________ box is a sequence of ______________ or ______________
before the start of transcription. It seems to help ____________________ RNA
polymerase by marking a point just __________________ the point at which
________________________ begins.
 Eukaryotic promoters are usually located _________________ the TATA box.
 ______________________ sequences regulate genes, and many
___________________ can bind to them.
 Cell __________________________ requires genetic specialization. Every
____________ in a multicellular organism contain the complete genetic code,
but they do not _________________ all of the available genes.
Regulation and Development
 _____________ genes control the organs and ________________ that develop
in various parts of an ____________________.
 A ______________________ in one of these master control genes can
completely change the __________________ that develop in specific parts of
the body.
 What is an example of a strange mutation in a fruit fly?
_________________________________________________________________
 Careful _____________________ of expression in these genes is essential for
____________________ development.