How are these pieces of music How are these pieces of music similar?similar?How are they How are they different?different?What is the result of their What is the result of their differencedifference

Compare and contrast the DNA molecule Compare and contrast the DNA molecule on the left with the RNA molecule on on the left with the RNA molecule on the rightthe right

Include 3 similarities and 3 Include 3 similarities and 3 differences between the two moleculesdifferences between the two molecules

Break into equal Break into equal lab groups and lab groups and use your Outreach use your Outreach Notes to create Notes to create a flow map showing how and a flow map showing how and where the process of protein where the process of protein synthesis takes place within a synthesis takes place within a cell.cell. Must include: Must include:

Transcription & Translation Transcription & Translation (what & where and how)(what & where and how)

& Organelles Involved& Organelles Involved

Lets take a look at the Lets take a look at the other groups projectsother groups projects

The genetic The genetic code is code is used as a used as a blueprint blueprint to make to make proteins.proteins.

We have looked at DNA. But how is We have looked at DNA. But how is this gentic code actually used for this gentic code actually used for anything?anything?

Lets Lets See!See!

Proteins are widely used in Proteins are widely used in cells to serve diverse cells to serve diverse functions. Some proteins functions. Some proteins provide the structural support provide the structural support for cells while others act as for cells while others act as enzymes to catalyze certain enzymes to catalyze certain reactions.reactions.

But, where do But, where do proteins come proteins come from? from?

Since the Since the beginning of beginning of evolution, cells evolution, cells have developed have developed the ability to the ability to synthesize synthesize proteins.proteins.

They can produce new proteins They can produce new proteins either for reproduction or to either for reproduction or to simply replace a degraded one.simply replace a degraded one.

Within the coil of DNA Within the coil of DNA lies all the lies all the information needed to information needed to produce everything in produce everything in the human body.  A the human body.  A strand of DNA may be strand of DNA may be millions, or billions, millions, or billions, of base-pairs long.  of base-pairs long.  Different segments of Different segments of the DNA molecule code the DNA molecule code for different for different characteristics in the characteristics in the body.  body. 

DNA is a complex double stranded DNA is a complex double stranded molecule that carries an molecule that carries an organisms genetic information in organisms genetic information in the form of a code of repeating the form of a code of repeating sub units. sub units. What do we What do we call the DNA call the DNA sub-unit sub-unit identified by identified by the X in the the X in the diagram on diagram on the right?the right?

A chromosome is a A chromosome is a large collection large collection of DNA that of DNA that contains many contains many genes and the genes and the support proteins support proteins needed to control needed to control these genes.these genes.

A gene is a A gene is a section of section of

a a chromosome chromosome (DNA) that (DNA) that codes for a codes for a proteinprotein

However, cells don't However, cells don't express all of their express all of their genes all of the time. genes all of the time. The Lipizzaner horses The Lipizzaner horses from Spain are pure from Spain are pure white as adults . . .white as adults . . .

. . . but . . . but are born are born blackblack

To manufacture proteins, To manufacture proteins, cells follow a very cells follow a very systematic 2 step procedure systematic 2 step procedure that first transcribes DNA in that first transcribes DNA in the nucleus into mRNA and the nucleus into mRNA and then translates then translates the mRNA into chains the mRNA into chains of amino acids of amino acids in the cells in the cells ribosomes. ribosomes.

has only a single strand of has only a single strand of nucleotides instead of two nucleotides instead of two strands strands

contains a different sugar contains a different sugar (ribose instead of (ribose instead of deoxyribose) deoxyribose)

contains the nitrogen base contains the nitrogen base uracil (U) instead of thymine uracil (U) instead of thymine (T) (T)

RNA is very similar to DNA except RNA is very similar to DNA except that it:that it:

• Ribosomal RNA (rRNA),Ribosomal RNA (rRNA), along along with protein, makes up the with protein, makes up the ribosomesribosomes

• Messenger RNA (mRNA)Messenger RNA (mRNA) copies copies DNADNA’’s code & carries the s code & carries the genetic information to the genetic information to the ribosomesribosomes

• Transfer RNA (tRNA)Transfer RNA (tRNA) transfers amino acids to transfers amino acids to the ribosomes where the ribosomes where proteins are synthesizedproteins are synthesized

The The ““mm”” in in ““mRNAmRNA”” stands for stands for ““messenger,messenger,”” because because mRNA copies genetic mRNA copies genetic information from DNA information from DNA (which is found in (which is found in the nucleus) and the nucleus) and carries it to carries it to another part of the another part of the cell (the cell (the ribosomes).ribosomes).

G T T C C G A G T T C C G A T CT C

Transcribe the DNA sequence below Transcribe the DNA sequence below into a strand of mRNAinto a strand of mRNA

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? ?

Where in a cell does the Where in a cell does the process below take place?process below take place?

A A A G G C T A A A G G C T A GA GT T T C C G A T T T C C G A T CT C

U U U C C G A U U U U C C G A U C C

A A A G G C T A A A G G C T A GA GT T T C C G A T T T C C G A T CT C

U U U C C G A U U U U C C G A U C C

What product is produced as a What product is produced as a result of this process?result of this process?

Codon Codon Codon Codon Codon Codon

O.K., weO.K., we’’ve gone

ve gone from DNA to mRNA.

from DNA to mRNA. How do proteins

How do proteins fit into all

fit into all this?this?

Think of the Think of the genetic code the genetic code the mRNA is carrying mRNA is carrying as a series of as a series of three-letter three-letter ““words.words.”” Each of Each of these three-these three-letter words is letter words is called a called a codoncodon..

Different codons Different codons code for different code for different amino acids. For amino acids. For example, the codon example, the codon for the amino acid for the amino acid methionine is AUG methionine is AUG (adenine, uracil, (adenine, uracil, guanine). The guanine). The codon for the amino codon for the amino acid serine is UCA acid serine is UCA (uracil, cytosine, (uracil, cytosine, adenine).adenine).

Another type of RNA, Another type of RNA, called tRNA (called tRNA (““tt”” stands stands for for ““transfertransfer””) matches ) matches the codons in mRNA to the codons in mRNA to the correct amino the correct amino acids.acids.

As the mRNA strand moves along the As the mRNA strand moves along the ribosome, the amino ribosome, the amino acids are joined in the acids are joined in the correct sequence to correct sequence to form a protein. This form a protein. This process is called process is called translationtranslation..

C C U

Proin

e

U C G

Ser

ine

A C C

Tryp

toph

an

G G A

Pro

ine

Codon Codon Codon Codon CodonCodon

U C G

Ser

ine

G U U

Valin

e

G

The diagram below shows a codon chart. A The diagram below shows a codon chart. A codon chart shows which codons code for codon chart shows which codons code for which amino acids.which amino acids.

This chart shows the amino acids coded for This chart shows the amino acids coded for by each of the 64 possible mRNA codons. To by each of the 64 possible mRNA codons. To find which amino acid the codon CAA codes find which amino acid the codon CAA codes for, follow these steps. (1) Look on the for, follow these steps. (1) Look on the left side of the chart to find the large left side of the chart to find the large row of codons that begin with C. (2) Move row of codons that begin with C. (2) Move across this row until you get to the across this row until you get to the column of codons whose second column of codons whose second base is A. (3) Move base is A. (3) Move down this column until down this column until you get to the row of you get to the row of codons whose third codons whose third base is A. The codon base is A. The codon CAA codes for the CAA codes for the amino acid glutamine.amino acid glutamine.

Suppose a DNA Suppose a DNA mutation led to mutation led to a change in a a change in a single mRNA single mRNA codon. Now codon. Now suppose this suppose this codon changed codon changed from GCC to GCG.from GCC to GCG.

By looking at the codon chart, you can By looking at the codon chart, you can see that both of these codons code for see that both of these codons code for the amino acid alanine. So even though the amino acid alanine. So even though the DNA and mRNA have changed, there is the DNA and mRNA have changed, there is no change in the protein!no change in the protein!

AUG CCU AUU GAU GGC CCA UAA GUU

How would a change in the sequence How would a change in the sequence of nucleotides in a DNA molecule of nucleotides in a DNA molecule affect the mRNA transcribed from affect the mRNA transcribed from the DNA molecule?the DNA molecule?Any change in the DNA would cause Any change in the DNA would cause a change in the mRNA molecule a change in the mRNA molecule

Methionine (start)

Leucine Theronine Stop

AUGAAUAAC

GUU GUCGUA GUG

CAUCAC

Compare and contrast the DNA molecule Compare and contrast the DNA molecule on the left with the RNA molecule on on the left with the RNA molecule on the rightthe right

Include 3 similarities and 3 Include 3 similarities and 3 differences between the two moleculesdifferences between the two molecules

Codon Codon Codon Codon Codon Codon

O.K., weO.K., we’’ve gone

ve gone from DNA to mRNA.

from DNA to mRNA. How do proteins

How do proteins fit into all

fit into all this?this?

Think of the Think of the genetic code the genetic code the mRNA is carrying mRNA is carrying as a series of as a series of three-letter three-letter ““words.words.”” Each of Each of these three-these three-letter words is letter words is called a called a codoncodon..

Different codons Different codons code for different code for different amino acids. For amino acids. For example, the codon example, the codon for the amino acid for the amino acid methionine is AUG methionine is AUG (adenine, uracil, (adenine, uracil, guanine). The guanine). The codon for the amino codon for the amino acid serine is UCA acid serine is UCA (uracil, cytosine, (uracil, cytosine, adenine).adenine).

Another type of RNA, Another type of RNA, called tRNA (called tRNA (““tt”” stands stands for for ““transfertransfer””) matches ) matches the codons in mRNA to the codons in mRNA to the correct amino the correct amino acids.acids.

As the mRNA strand moves along the As the mRNA strand moves along the ribosome, the amino ribosome, the amino acids are joined in the acids are joined in the correct sequence to correct sequence to form a protein. This form a protein. This process is called process is called translationtranslation..

C C U

Proin

e

U C G

Ser

ine

A C C

Tryp

toph

an

G G A

Pro

ine

Codon Codon Codon Codon CodonCodon

U C G

Ser

ine

G U U

Valin

e

G

The diagram below shows a codon chart. A The diagram below shows a codon chart. A codon chart shows which codons code for codon chart shows which codons code for which amino acids.which amino acids.

This chart shows the amino acids coded for This chart shows the amino acids coded for by each of the 64 possible mRNA codons. To by each of the 64 possible mRNA codons. To find which amino acid the codon CAA codes find which amino acid the codon CAA codes for, follow these steps. (1) Look on the for, follow these steps. (1) Look on the left side of the chart to find the large left side of the chart to find the large row of codons that begin with C. (2) Move row of codons that begin with C. (2) Move across this row until you get to the across this row until you get to the column of codons whose second column of codons whose second base is A. (3) Move base is A. (3) Move down this column until down this column until you get to the row of you get to the row of codons whose third codons whose third base is A. The codon base is A. The codon CAA codes for the CAA codes for the amino acid glutamine.amino acid glutamine.

Suppose a DNA Suppose a DNA mutation led to mutation led to a change in a a change in a single mRNA single mRNA codon. Now codon. Now suppose this suppose this codon changed codon changed from GCC to GCG.from GCC to GCG.

By looking at the codon chart, you can By looking at the codon chart, you can see that both of these codons code for see that both of these codons code for the amino acid alanine. So even though the amino acid alanine. So even though the DNA and mRNA have changed, there is the DNA and mRNA have changed, there is no change in the protein!no change in the protein!

AUG CCU AUU GAU GGC CCA UAA GUU

How would a change in the sequence How would a change in the sequence of nucleotides in a DNA molecule of nucleotides in a DNA molecule affect the mRNA transcribed from affect the mRNA transcribed from the DNA molecule?the DNA molecule?Any change in the DNA would cause Any change in the DNA would cause a change in the mRNA molecule a change in the mRNA molecule

Methionine (start)

Leucine Theronine Stop

AUGAAUAAC

GUU GUCGUA GUG

CAUCAC