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 Synthesis 13.4 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.

Chromosomal mutations 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 Wasp Notice 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 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 Apply Concepts Show how you could use words to model a frameshift mutation (hint: use a sentence) Use Models Use the words in this sentence to model a substitution mutation.