RNASay Hello to DNA’s little friend!

Engage Essential Question Explain

Describe yourself to long lost uncle.

How do the mechanisms of genetics and the functions of nucleic acids give you the traits that make you who you are?

The steps and molecules involved in protein synthesis.

Engage

Your long lost uncle will be arriving at the airport this weekend and you are responsible for picking him up while everyone else finish preparing for the welcoming party at your house. Send your uncle a text with a description of yourself with enough detail for him to be able to recognize you among a large group of strange people.

Why do you look the way you do?

Each of your cells has the instructions needed to make you look, act and be who you are.

You just texted your uncle a list of your traits.

DNA is in your chromosomesYou inherited 23 chromosomes from each parent.

So your parents gave you your traits.

Each chromosome has segments of nucleotides called

genes.

Each gene has instructions; (DNA sequence = Genetic Code = Genome)

Humans have 23 pairs of chromosomes

Human Genome = all genes in humans = 30,000 – 40,000 genes

Each gene makes a protein for a specific trait

DNA is only the code

• RNA molecules make the actual workers that make you who you are.

• Proteins (polypeptides) are the biological workers that make you who you are.

Proteins are made up of amino acids

DiversityAll living things are made up of the same molecules:

DNA nucleotides

A = T

C = G

RNA nucleotides

A = U

C = G

20 amino acids (make up all possible proteins)

Is nicotine and alcohol addiction a trait coded by your genes?

• Students are sequencing genes related to nicotine addiction. Beginning in 2001, students are characterizing variation in the gene called CYP2A6, which codes for an enzyme involved in the excretion of nicotine. The student project has the potential for identifying new variants of this gene and ultimately contributing to our understanding of nicotine addition.

What is genetic variation and how is it related to drug addiction?

• Each of us is strongly aware of how we are different from everyone else our own uniqueness. People come in all different shapes, sizes, and colors, with a wide range of abilities, talents, and personalities. We even vary in the way we respond to drugs. What determines our characteristics, or traits? Our traits are determined by a variety of factors, including genetics, our environment, and our culture.

What genes are involved in nicotine addiction?

An exciting revelation of the Human Genome Project is how similar all human beings are on the genetic level we are all 99.9% the same! This means that a comparison of the DNA sequence of two individuals would reveal approximately one different nucleotide for every thousand nucleotides of sequence. Some of these nucleotide differences do not have any effect at all, while others change a particular genetic trait. In rare cases, differences in the nucleotide sequence can have extreme consequences for the individual, but usually they result in the subtle differences that make each of us unique.

How do we get the DNA sequence?

• Start reading from bottom of image and move up.

• Use circle or lines to help you keep track of bases.

• AAT TCC CGG GGA T…

The original CYP2A6 gene.

Read and write the

DNA sequence from the

gel electrophoresis picture.

2 STEPS and 3 RNA molecules IN MAKING A PROTEIN

Day 2

3 types of RNA• mRNA – (messenger) -

copies DNA

• rRNA – (ribosomal) –

reads codons on mRNA

• tRNA – (transfer) – places amino acid on each codon of mRNA

DNA and RNA nucleotides

– Review

– New information

• DNA nucleotidesA = TG = C

• RNA nucleotidesA = U

(Uracil)G = C

RNA Differs from DNARNA Differs from DNA

1. RNA has a sugar ribose2. RNA contains the base uracil (U) (A=U C=G)3. RNA molecule is single-stranded4. In the nucleus

RNARNA DNADNA

1. DNA has a sugar deoxyribose2. DNA has thymine (T) (A=T C=G)3. DNA is double-stranded4. Leaves the nucleus goes to ribosome

Make a T Chart!!!

2 Steps of Protein Synthesis

1 2

TranscriptionT

• DNA is copied by mRNA

• Occurs in nucleus

• mRNA leaves nucleus with instructions to make a protein.

• mRNA finds a ribosome in cytoplasm or on rough endoplasmic reticulum

Translation

• rRNA (in ribosome) reads nucleotides on mRNA

• 3 nucleotides on mRNA = 1codon

• 1 codon = 1 amino acid

Translation

• tRNA brings the amino acid to each codon

• Amino acids form long chains called polypeptides or proteins

Practice

DNA – TAC CAG ATC ATT

mRNA - AUG ___ ___ __

a.a. - met ___ ___ ___

1. Transcribe DNA into mRNA

2. Translate mRNA into amino acid chain.

alanine – alaarginine – argasparagine – asnaspartic acid – aspcysteine – cysglutamine – glnglutamic acid – gluglycine – glyhistidine – hisisoleucine – ileleucine – leulysine – lysmethionine – metphenylalanine – pheproline – proserine – serthreonine – thrtryptophan – trptyrosine – tyr valine – val

Label each part

1. Explain the process and molecules involved in protein synthesis.

2. Why is RNA, DNA’s “little friend”?

Complete amino acid chain for original CYP2A6 gene

• Go to your DNA sequence of the original CYP2A6 gene.

• Transcribe DNA sequence into mRNA.

• Translate mRNA into amino acid chain.

• Next transcribe and translate the DNA sequence of 5 variant genes for CYP2A6.

Molecule Gene Name* variant

Sequence: separate each codon on mRNA with / in between circle each amino acid

DNA CYP2A6*2 TAC GCG GGC TTC CTC ATG GAC GCC CAC CGG GGC ACT

mRNA AUG /CGC/CCG/ AAG/ GAG/ / / / / / / STOP

a.a. MET ARG PRO ARG GLU

DNA CYP2A6*5 TAC CAA AGT CAC CTA AGG ACA TTG ACG TGT CCC AAC ATT

mRNA AUG/ / / / / / / / / / / / /

a.a.

DNA CYP2A6*6 TAC TAT TCA GCA ACG GGG AGC GCG CCA AGC AGC TCC ATC

mRNA / / / / / / / / / / / / /

a.a.

DNA CYP2A6*7 TAC AGT AGT CAC CTA AGG ACA CTG ACG TGT CCC CCA ACT

mRNA / / / / / / / / / / / / /

a.a.

DNA CYP2A6*8 TAC TTT CCA CTA AAC TAA ACC ATG AGC TTC CTG CCC ATT

mRNA

a.a.

Explain

• The steps and molecules involved in protein synthesis.

• Use labeled diagrams to help your explanation.

Essential QuestionHow do the mechanisms of genetics and

functions of nucleic acids give you the traits that make you who you are?

• Use the example of the nicotine addiction gene to construct your answer.

• Did changes in DNA of variant genes affect the protein being made?

• How do you know?

Use a ruler or straight edge to read the order of DNA nucleotides.Start at the bottom of picture of the gel.You can use circles, highlighter or lines to group them into 3’s.

DNA AAT TCC CGG G…

mRNA

Amino acid

DNA

mRNA

Amino acid

DNA

mRNA

Amino acid

DNA

mRNA

Amino acid

Molecule Gene Name* variant

Sequence: separate each codon on mRNA with / in between circle each amino acid

DNA CYP2A6*2 TAC GCG GGC TTC CTC ATG GAC GCC CAC CGG GGC ACT

mRNA AUG /CGC/CCG/ AAG/ GAG/ / / / / / / STOP

a.a. MET ARG PRO ARG GLU

DNA CYP2A6*5 TAC CAA AGT CAC CTA AGG ACA TTG ACG TGT CCC AAC ATT

mRNA AUG/ / / / / / / / / / / / /

a.a.

DNA CYP2A6*6 TAC TAT TCA GCA ACG GGG AGC GCG CCA AGC AGC TCC ATC

mRNA / / / / / / / / / / / / /

a.a.

DNA CYP2A6*7 TAC AGT AGT CAC CTA AGG ACA CTG ACG TGT CCC CCA ACT

mRNA / / / / / / / / / / / / /

a.a.

DNA CYP2A6*8 TAC TTT CCA CTA AAC TAA ACC ATG AGC TTC CTG CCC ATT

mRNA

a.a.

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