Download RNA DNA

RNA
Say Hello to DNA’s little friend!
Engage
Essential Question
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?
Explain
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 chromosomes
You 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
Diversity
All 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?
Read and write the
DNA sequence from the
gel electrophoresis
picture.
• 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.
Day 2
2 STEPS and 3 RNA molecules
IN MAKING A PROTEIN
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
• DNA nucleotides
A = T
G =C
– New information • RNA nucleotides
A = U (Uracil)
G =C
RNA Differs from DNA
RNA
1. RNA has a sugar
ribose
2. RNA contains the
base uracil (U)
(A=U C=G)
3. RNA molecule is
single-stranded
4. In the nucleus
DNA
1. DNA has a sugar
deoxyribose
2. DNA has thymine
(T)
(A=T C=G)
3. DNA is doublestranded
4. Leaves the
nucleus goes to
ribosome
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
1.
Transcribe DNA into mRNA
2.
Translate mRNA into amino
acid chain.
DNA –
TAC CAG ATC ATT
mRNA - AUG ___ ___
__
a.a. -
___
met ___ ___
alanine – ala
arginine – arg
asparagine – asn
aspartic acid – asp
cysteine – cys
glutamine – gln
glutamic acid – glu
glycine – gly
histidine – his
isoleucine – ile
leucine – leu
lysine – lys
methionine – met
phenylalanine – phe
proline – pro
serine – ser
threonine – thr
tryptophan – trp
tyrosine – 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/
a.a.
MET ARG PRO ARG GLU
DNA
CYP2A6*5
mRNA
/
/
/
/
/
/ STOP
TAC CAA AGT CAC CTA AGG ACA TTG ACG TGT CCC AAC ATT
AUG/
/
/
/
/
/
/
/
/
/
/
/
/
a.a.
DNA
CYP2A6*6
mRNA
TAC TAT TCA GCA ACG GGG AGC GCG CCA AGC AGC TCC ATC
/
/
/
/
/
/
/
/
/
/
/
/
/
a.a.
DNA
CYP2A6*7
mRNA
TAC AGT AGT CAC CTA AGG ACA CTG ACG TGT CCC CCA ACT
/
/
/
/
/
/
/
/
/
/
/
/
a.a.
DNA
mRNA
a.a.
CYP2A6*8
TAC TTT CCA CTA AAC TAA ACC ATG AGC TTC CTG CCC ATT
/
Explain
• The steps and
molecules
involved in protein
synthesis.
• Use labeled
diagrams to help
your explanation.
Essential Question
How 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
mRNA
Amino
acid
DNA
mRNA
Amino
acid
DNA
mRNA
Amino
acid
DNA
mRNA
Amino
acid
AAT
TCC
CGG
G…
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/
a.a.
MET ARG PRO ARG GLU
DNA
CYP2A6*5
mRNA
/
/
/
/
/
/ STOP
TAC CAA AGT CAC CTA AGG ACA TTG ACG TGT CCC AAC ATT
AUG/
/
/
/
/
/
/
/
/
/
/
/
/
a.a.
DNA
CYP2A6*6
mRNA
TAC TAT TCA GCA ACG GGG AGC GCG CCA AGC AGC TCC ATC
/
/
/
/
/
/
/
/
/
/
/
/
/
a.a.
DNA
CYP2A6*7
mRNA
TAC AGT AGT CAC CTA AGG ACA CTG ACG TGT CCC CCA ACT
/
/
/
/
/
/
/
/
/
/
/
/
a.a.
DNA
mRNA
a.a.
CYP2A6*8
TAC TTT CCA CTA AAC TAA ACC ATG AGC TTC CTG CCC ATT
/
alanine – ala
arginine – arg
asparagine – asn
aspartic acid – asp
cysteine – cys
glutamine – gln
glutamic acid – glu
glycine – gly
histidine – his
isoleucine – ile
leucine – leu
lysine – lys
methionine – met
phenylalanine – phe
proline – pro
serine – ser
threonine – thr
tryptophan – trp
tyrosine – tyr
valine – val