Warm-Up / EOC Prep 1. A segment of a DNA strand has the following bases: TAC GAT What is the complementary strand of DNA? A. UAG CAU B. TAG CAT C. ATG CTA D. AUG CUA 2. Which relationship is most similar to the relationship below? tRNA : ribosome A. book : publisher B. truck : factory C. key : lock D. baker : pie

Agenda Warm-up Notes- Mutations Mutation Practice WS BINGO (If we have time) DNA Quiz Clean-up Cool-Down

Mutations and Gene Regulation

Remember: In Eukaryotes, DNA is found in the nucleus. For the most part, all of the cells in an organism’s body have the same DNA. However, we have learned in the past that cells are specialized for specific tasks and parts of the body. How can they be specialized but have the exact same DNA, the exact same instructions?

Cell differentiation is the way that cells become different from each other as they go through mitosis. At first, all cells are the same and are not specialized. These cells are called stem cells. As they grow and divide they become differentiated and specialized into heart cells, brain cells, liver cells, etc.

The differentiation of cells, despite the fact that all cells have the same DNA, occurs due to gene regulation. Both prokaryotic and eukaryotic cells can regulate which genes are expressed and which are not, depending on the cell’s needs.

Cell Organization Review Specialized cells have specific jobs. A group of similar cells working together to perform the same function is called a tissue. Ex: muscle, epithelial, connective, nervous A group of similar tissues working together to perform the same function is called an organ Ex: heart A group of similar organs working together to perform the same function is called an organ system. Ex: circulatory system

The four levels of organization: Cell

2. Tissue Four types: muscle, connective, epithelial, nervous

3. organ

4. organ system

As different cells respond to the environment they produce different types and amounts of proteins by “turning on” some genes and “turning off” other genes. Remember: A gene is a segment of DNA located on a chromosome that codes for a specific hereditary trait. This protein production is what specializes different cells for different jobs.

Turning on and off genes can be an advantage or a disadvantage to the cell. Gene regulation can cause the overproduction or underproduction of proteins as well as the production of proteins at incorrect times. An overproduction of proteins can cause cancer (the uncontrolled growth of cells), however, overproduction of proteins can also help the body, such as in injury repair

Just like poor gene regulation, mutations can also cause problems in cells.

A mutation is a change in the nucleotide- base sequence of a gene or DNA molecule When the cell copies its DNA, the enzyme DNA polymerase is in charge of proofreading the new DNA strand for errors. If it makes an error and doesn’t correct it, a mutation occurs.

Mutations can disrupt the functions of proteins.

Examples DNA: TAC-GGC-GAG-TAG-CCT RNA: AUG-CCG-CUC-AUC-GGA AA: Met - Pro -Leu -Iso -Gly These amino acids in this order make up a specific protein that is needed by the body.

Examples If one DNA nucleotide is changed, look what happens to the protein… DNA: TAC-GTC-GAG-TAG-CCT RNA: AUG-CAG-CUC-AUC-GGA AA: Met - Glu -Leu -Iso -Gly Now a point mutation has been made, or perhaps an amino acid sequence that is different and will do nothing.

Examples A different type of mutation can occur called a frame-shift mutation. What would happen if DNA Polymerase accidently removed one of the nucleotides in the original DNA sequence? DNA: TAC-GGC-GAG-TAG-CCT DNA: TAC-GGC-AGT-AGC-CT RNA: AUG-CCG-UCA-UCG-GA AA: Met - Pro -Ser -Ser - --- X

Types of Mutations Gene Mutations Point Mutation (not serious usually) Frame Shift Mutations (serious) Insertion Deletion Chromosome Mutations (all very serious) Deletion Insertion Inversion Translocation

Types of Gene Mutations

Types of Chromosome Mutations

REVIEW What is a mutation?

A change in a nucleotide base sequence

Name that mutation: THE CAT SAT THE TAC SAT

Inversion

Name that mutation: THE CAT SAT  THE CT SAT

Deletion

Name that mutation: THE CAT SAT  THE CATTA SAT

Insertion

Name that mutation: THE CAT SAT  ITH ECA TSA

Frameshift mutation

Mutation Practice If your birthday is.. Jan-Mar: insertion Apr-June: deletion July-Sept: inversion Oct-Dec: point mutation Mutate this mRNA strand according to your birthday. ACU CGA ACA

Now.. Take the original sequence and translate it. Also take your mutated sequence and translate it. Did the amino acid chain change because of the mutation?

Mutation Practice If your birthday is.. Jan-Mar: point mutation Apr-June: insertion July-Sept: deletion Oct-Dec: inversion Mutate this mRNA strand according to your birthday. CAC UAG AGU

Now.. Take the original sequence and translate it. Also take your mutated sequence and translate it. Did the amino acid chain change because of the mutation?

Mutation Practice If your birthday is.. Jan-Mar: inversion Apr-June: point mutation July-Sept: insertion Oct-Dec: deletion Mutate this mRNA strand according to your birthday. UCC GAC GCA

Now.. Take the original sequence and translate it. Also take your mutated sequence and translate it. Did the amino acid chain change because of the mutation?

Mutation Practice If your birthday is.. Jan-Mar: deletion Apr-June: inversion July-Sept: point mutation Oct-Dec: insertion Mutate this mRNA strand according to your birthday. ACT CGA UCG

Now.. Take the original sequence and translate it. Also take your mutated sequence and translate it. Did the amino acid chain change because of the mutation?

Whiteboards & Markers Away!

Complete the Mutation Practice worksheet.

Complementary DNA Strand TCTAAC CTTAAG GAGATC AGTCAG CAGGTT AACGUC GCTACG CGAATT

Transcribe DNA to mRNA ATCGAA GGCATA CTAGCA TTCAGG AGTCAT GTCAGT CCAGGT AATTGC

Reverse Transcription: mRNA to DNA AUGCAA UGAACC AUGCCA GUCACU ACUGUA CGUCAC UCGACC ACGUUA

Translate: mRNA to protein chain AUGCAA UGAACC AUGCCA GUCACU ACUGUA CGUCAC UCGACC ACGUUA

Cool-Down 1- What is the difference between transcription and translation (consider inputs and outputs)? 2- A mutation changes the original sequence of A- T-T-C-G-A to T-T-A-C-G-A. What kind of mutation was this? Did it shift the reading frame? 3- Fictional: in the battle between DNA and protein, who makes the stronger case for determining who you are as a person?

Name the correct mutation! Mutation Practice Name the correct mutation! Normal Gene: ACA TCA CCG Mutation # 1: ACG TCA CCG Mutation # 2: ACA ACT CCG Mutation # 3: AAT CAC CG

Name the correct mutation! Mutation Practice Name the correct mutation! Normal Gene: TCG CCG ACG Mutation # 1: TCT GCC GAC G Mutation # 2: TCG CCG CCG ACG Mutation # 3: GCC GCT ACG