how do we get proteins?

http://www.math.fsu.edu/~quine/IntroMathBio_04/Proteins/myoglobin_geis.jpg

myoglobin

When DNA copies…..

• It copy's in a very specific order. It copies 5’-3’ from a 3’-5’ Template.

• That means the DNA strand is in the following order…

DN

A

• That means the DNA strand is in the following order…

• That means the DNA strand is in the following order…

• That means the DNA strand is in the following order…

• That means the DNA strand is in the following order…

• That means the DNA strand is in the following order…

Double Helix

Nucleotides: basic molecule of DNA

Pyrimidine

Nucleotides: basic molecule of DNA

Purine

Pyrimidines and Purines

Made up of a

1.Sugar (5 carbon)

2.Phosphate group

3.Nitric Base

DNA Replication

• http://www.johnkyrk.com/DNAreplication.html

Differences between RNA and DNA

• RNA has only a SINGLE Strand (DNA is Double Stranded)

• RNA contains ribose instead of deoxyribose

• RNA polymerase can start the RNA transcription without a primer

Differences between RNA and DNA

• RNA uses Uracil(U) instead of Thymine(T)• More errors occur in an RNA copy than in DNA

copy of nucleotides (103 more than in DNA)• FACT: DNA has a transcription error

approximately every 107 nucleotides. RNA has an error approximately every 104 !

Differences between RNA and DNA

• WHY are there more errors in RNA Transcription?

• One of several reasons is that in rare instances Uracil can also bond with Guanine

Is this a Bad thing?

• WHY are there more errors in RNA Transcription?

• One of several reasons is that in rare instance Uracil can also bond with Guanine

• RNA is a temporary copy in Eukaryotes

Types of RNA

• mRNA= messenger RNA• codes for a protein

Types of RNA

• tRNA= transfer RNA• central to protein synthesis as adaptors

between mRNA and amino acids

Types of RNA

• rRNA= ribosomal RNA• form the basic structure of the ribosome

and catalyze protein synthesis

• Transcription- the synthesis of RNA under DNA (occurs in the nucleus)

• Translation- the actual synthesis of a polypeptide coded for by the mRNA. (changing the base sequence of the mRNA molecule into a chain of amino acids that form a polypeptide. For our purposes a protein.)

An mRNA copy is made from DNA in the Nucleus

The DNA strand from which the mRNA is copied is the

TEMPLATE STRAND

The mRNA leaves the nucleus and enters a ribosome (made up of rRNA)

tRNA collects a specific amino acids present in the cell and brings it to the ribosome

The anticodon of the tRNA matches up with its counterpart codon on the mRNA

When the mRNA & the tRNA link up the amino acid detaches and is connected to the adjacent amino acid

This chain of amino acids is a protein (polypeptide)

rRNARibosome

rRNA mRNA enters the “A” site of the ribosome

rRNA When the first codon reaches the “P” site the tRNA brings down the amino acid and links up with the mRNA

rRNA The “E” site is where the amino acid separates form the tRNA and links up to adjacent amino acids. This is where the MRNA and tRNA leave the ribosome

ANTICODONS

Anticodon

•Anticodons specify which amino acid a tRNA collects

•The anticodon then pairs up with its corresponding codon

ANTICODONS

Anticodon

•So for example...

•The anticodon AGU would pair with the codon UCA.

•THEY ARE OPPOSITES OF EACH OTHER

So What's a codon?

Codon• This basic unit of genetic code is 3

nucleotides long

• It specifies a specific amino acid

• Each codon only specifies 1 amino acid (BUT…an amino acid may have several different codons that code for it)

http://images.google.com/imgres?imgurl=http://biology.kenyon.edu/courses/biol114/Chap05/trna-1.gif&imgrefurl=http://biology.kenyon.edu/courses/biol114/Chap05/Chapter05.html&h=382&w=283&sz=37&tbnid=G8z7JoxTdy0J:&tbnh=119&tbnw=88&hl=en&start=5&prev=/images%3Fq%3DtRNA%26svnum%3D50%26hl%3Den%26lr%3D%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official_s%26sa%3DG

THE END

http://www.chemistry.emory.edu/faculty/lynn/research/dna/template.gif

When DNA copies…..

• It copy's in a very specific order. It copies 5’-3’ from a 3’-5’ Template.

• That means the DNA strand is in the following order…

DN

A

• That means the DNA strand is in the following order…

• That means the DNA strand is in the following order…

• That means the DNA strand is in the following order…

• That means the DNA strand is in the following order…

• That means the DNA strand is in the following order…

Where credit is due• http://homepages.strath.ac.uk/~dfs97113/BB310/img002.jpg• http://fig.cox.miami.edu/~cmallery/150/gene/16x5bc.jpg• http://opbs.okstate.edu/~petracek/Chapter%2027%20Figures/Fig

%2027-08a.GIF• http://imglib.lbl.gov/ImgLib/COLLECTIONS/BERKELEY-LAB/

RESEARCH-1991-PRESENT/LIFE-SCIENCES/images/96703355.lowres.jpeg

• http://www.umanitoba.ca/afs/plant_science/COURSES/CYTO/l12/replication.gif

• http://www.accessexcellence.org/RC/VL/GG/images/rna.gif• http://ghs.gresham.k12.or.us/science/ps/sci/ibbio/chem/notes/

chpt14/pyrimidine.gif• http://www.daviddarling.info/images/uracil.jpg• http://www.carolguze.com/images/cellorganelles/ribosome.jpg• http://perso.wanadoo.fr/marxiens/sciences/codons.jpg