Warm Up In your notes, Transcribe this DNA code: DNA: TAC CGT TCA ACT mRNA: AUG GCA AGU UGA ….and translate: Amino acids: methionine-alanine-serine-stop

On a clean sheet of paper, Transcribe this DNA code: DNA: GAC AAG TCC ACA ATC mRNA: CUG UUC AGG UGU UAG

On a clean sheet of paper, Transcribe this DNA code: DNA: GAC AAG TCC ACA ATC mRNA: CUG UUC AGG UGU UAG ------------------------------------------------------------- tRNA: GAC AAG UCC ACA AUC NUCLEUS CYTO-PLASM

On a clean sheet of paper, Transcribe this DNA code: DNA: GAC AAG TCC ACA ATC mRNA: CUG UUC AGG UGU UAG -------------------------------------------------------- tRNA: GAC AAG UCC ACA AUC Amino acid sequence: leucine-phenylalanine-(etc.) polypeptide NUCLEUS CYTO-PLASM

And How They Lead to Evolution Mutations And How They Lead to Evolution

Evolution Mistakes occur in nature. These mistakes can lead to advantages and disadvantages. When these mistakes are advantageous, over a long period of time, they can lead to evolution.

Mutations Cells make mistakes DNA replication or mitosis. These mistakes are called mutations.

Mutations Mutations are changes in genetic information. Mutations will not affect offspring unless it is in a sperm or egg cell

1) A mutation is A change in RNA code A change in genetic information A change in cell structure A group of unpaired bases

Two Types of Mutations Gene mutations Chromosomal mutations changes in a single gene Chromosomal mutations changes in an entire chromosome

Gene Mutations Point Mutations Changes in one or a few nucleotides Generally occur during DNA replication

Gene Mutations Point mutations include substitutions, insertions, and deletions.

2) Two types of mutations are Genetic and cellular RNA and DNA Nuclear and ribosomal Gene and chromosomal

3) Gene mutations usually happen when The cell is undergoing metaphase I The DNA is replicating The nucleus is dividing The gametes fuse

Substitutions (video) In a substitution, one base is changed to a different base. Substitutions usually affect no more than a single amino acid, and sometimes they have no effect at all. (eg. CCC and CCA code for the same amino acid)

Insertions and Deletions (video) Point mutations in which one base is inserted or removed from the DNA sequence. This mutation is dramatic, because it shifts all the codons.

Insertions and Deletions Also known as “frameshift” mutations because they shift the reading frame of the genetic message. These can change every amino acid in the sequence, making the protein nonfunctional.

4) What type of gene mutation is this: DNA:        TAC    GCA    TGG    AAT DNA:        TAC    GTA    TGG    AAT Substitution Deletion Insertion Polyploidy Gene Mutation animation

5) What could result from a deletion mutation? a) Deletions are generally not harmful b) A nonfunctional protein c) nondisjunction d) Deletions cause substitutions

6) What type of gene mutation would this represent: THE FAT CAT ATE THE RAT   TEF ATC ATA TET HER AT Nonsense Insertion Deletion Substitution

Chromosomal Mutations Involve changes in the number or structure of chromosomes. Can change the location of genes on chromosomes. Can change the number of copies of some genes. (video)

Deletion Deletion involves the loss of all or part of a chromosome.

Duplication Duplication produces an extra copy of all or part of a chromosome.

Inversion Inversion reverses the direction of parts of a chromosome.

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

7) Which of the following is NOT a form of chromosomal mutation: a) Deletion b) Duplication c) Inversion d) Insertion e) Translocation

8) Involves an extra copy of all or part of a chromosome: a) Deletion b) Duplication c) Inversion d) Translocation

9) Which of the following is the name of a type of chromosomal mutation AND a type of gene mutation? a) Deletion b) Duplication c) Inversion d) Translocation

Mutagens Some mutations arise from mutagens: chemical or physical agents in the environment that cause mutations. Some forms of Radiation are mutagens

Mutagens Some compounds interfere with base-pairing. HNO3 converts C to U Some compounds interfere with base-pairing. Others weaken the DNA strand, causing breaks and inversions (chromosomal mutations). Cells can sometimes repair the damage; if not, the DNA base sequence changes permanently

Mutagenic heterocyclic amines are generated in foods when they are cooked at temperatures over 150°C. ehp03.niehs.nih.gov/.../Suppl-6/felton-full.html

Harmful and Helpful Mutations The effects of mutations on genes vary widely. Some have little or no effect. Some produce beneficial variations. Some negatively disrupt gene function.

Harmful Effects Some of the most harmful mutations are those that dramatically change protein structure or gene activity. The defective proteins produced by these mutations can disrupt normal biological activities, and result in genetic disorders.

Effects of Mutations-Beneficial Stressful environmental conditions may cause some bacteria to increase mutation rates. This can actually be helpful to the organism Gives bacteria new traits, such as the ability to consume a new food source or to resist a poison in the environment.

Beneficial Effects Some of the variations produced by mutations can be highly advantageous to an organism or species.

Beneficial Effects Mutations may produce proteins with new or altered functions that can be useful to organisms in changing environments. For example, mutations have helped many insects resist chemical pesticides.

Beneficial Effects Increased “fit”ness  increased reproduction!! This mutation is then carried on to the offspring, eventually leading to new and improved traits.

10) Which of the following statements is accurate: a) All gene mutations are harmful b) No chromosomal mutations are beneficial c) Some mutations have no effect d) Mutations cannot lead to evolution

12) Classify the following type of mutation . a) Point mutation b) Gene mutation c) Chromosomal mutation d) Frameshift mutation

12) Mutant 1 is the result of a ______ because Part of the chromosome reverses direction. a) Deletion b) Duplication c) Inversion d) Translocation