Chapter 10: Genes and Chromosomes
Section 2: Mutations
Mutations

A change in the genetic material of a cell is known as a _____________________

Not all mutations are harmful

Many mutations either have no effect or cause slight, harmless changes

Once in awhile a mutation may be ________________________________ to an
organism

Mutations may occur in any cell

Mutations that affect the ____________________________________________,
or germ cells, are called ____________________________________________

Mutations that affect the other cells of the body are called ___________________
________________________________

Because they do not affect the reproductive cells, somatic mutations are
_________________________________________________

Many ____________________________ are caused by somatic mutations

Both somatic and germ mutations can occur at two levels – the level of
___________________________________ and the level of _________________

Chromosomal mutations involve segments of chromosomes, whole
chromosomes, and even entire sets of chromosomes

Gene mutation involve individual genes
Chromosomal Mutations

Whenever a _____________________________________________________
occurs, there is a change in the number or structure of chromosomes

There are four types of chromosomal mutations
o ____________________________________
o ____________________________________
o ____________________________________
o ____________________________________
Deletion

A deletion involves the ________________ of part of a chromosome
Duplication

The opposite of a deletion is a duplication, in which a segment of a chromosome
is __________________________
Inversion

When part of a chromosome becomes oriented in the _______________________
of its usual direction, the result is an inversion
Translocation

A translocation occurs when part of one chromosome ______________________
and attaches to another, nonhomologous chromosome

In most cases, nonhomologous chromosomes exchange segments, so that two
translocations occur at the same time
Chromosomal Mutations

Chromosomal mutations that involve whole chromosomes or complete sets of
chromosomes result from a process known as _____________________________

Nondisjunction is the failure of homologous chromosomes to separate normally
during meiosis

When one extra chromosome is involved, nondisjunction results in an
___________________________________ of a chromosome in one cell and a
___________________ of that chromosome in another cell

Nondisjunction can involve more than one chromosome
o _____________________________
o _____________________________

_______________________________

Almost always _____________________ in animals

However, polyploid plants are often larger and hardier than
normal plants
Mutations in Genes

Mutations can occur in individual genes and can seriously affect gene function

Any chemical change that affects the DNA molecule has the potential to produce
_____________________________________

The smallest changes, known as _______________________________________,
affect no more than a single nucleotide

However, if a single base is inserted or deleted, the groupings are shifted for every
codon following the point mutation

Such _____________________________________________ can completely
change the polypeptide product produced by a gene