1 Explain What is a frameshift mutation and give an example

Infer The effects of a mutation are not always visible. Choose a species and explain how a biologist might determine whether a mutation has occurred and, if so, what type of mutation it is

2 Review List four effect mutations can have on genes Apply Concepts What is the significance of

mutations to living things

CH 13 RNA AND PROTEIN SYNTHESIS13.4 Mutations

Mutations

Heritable changes in genetic information

Cells make mistakes in copying their own DNA, inserting the wrong base or even skipping a base as a strand is put together.

Gene mutations Produce changes in a single gene

Chromosomal mutations Produce changes in whole chromosomes.

Gene mutations

Point mutations Changes in one or a few nucleotides Occur at a single point Include substitutions, insertions, and deletions.

Substitutions

One base is changed to a different base Affect one amino acid or none.

Insertions and Deletions

One base is inserted or removed from the DNA sequence

Results in codons being shifted Changes all amino acids after that point Frame shift mutation.

Chromosomal Mutations

Changes gene location on chromosomes and can even change the number of copies of some genes

Includes deletion, duplication, inversion, and translocation.

Deletion

Involves the loss of all or part of a chromosome.

Inversion

Reverses the direction of parts of a chromosome.

Translocation

Occurs when part of one chromosome breaks off and attaches to another.

Duplication

Produces an extra copy of all or part of a chromosome.

Mutations

Genetic material can be altered by natural events or by artificial means DNA inserts an incorrect base roughly once in every

10 million bases Mutagen: chemical or physical agent in environment

such as pesticides, cigarette smoke, and radiation

DNA does repair some damage.

Effects of Mutations

Most people think they are harmful Some are harmful Some are helpful Most have no effect A few are lethal

Mutations are needed at the species level.

Polyploidy

Condition in which an organism has extra sets of chromosomes

Polyploid plants are often larger and stronger than diploid plants.

Small mutations in DNA can cause huge changes in the proteins that are synthesized. Similarly, small changes in a word can dramatically alter its meaning

Milk Mile Wile Wise Wisp WaspNotice that each word differs from the previous word

by just one letter and none of the words is meaningless. Think of these changes as “point mutations.”

Analyze and Conclude

1. Apply Concepts Start with the word gene, and change it letter by letter to make new words. Make sure each new word is an actual word (not proper noun). Write at least 4 “point mutations” of the word gene

2. Apply Concepts Show how you could use words to model a frameshift mutation (hint: use a sentence)

3. Use Models Use the words in this sentence to model a substitution mutation.