DNA & RNA +DNA & RNA +PROTEIN SYNTHESISPROTEIN SYNTHESIS

DNA DNA (Deoxyribonucleic acid) is the code inside (Deoxyribonucleic acid) is the code inside all living organisms.all living organisms.

The first model of DNA was built by The first model of DNA was built by WatsonWatson & & CrickCrick in in 19531953 and they won the and they won the Nobel PrizeNobel Prize for for it.it.

DNA is a DNA is a double helixdouble helix or twisted ladder or twisted ladder

DNA is made up of DNA is made up of nucleotides nucleotides Nucleotides….Nucleotides….

are made up of a are made up of a sugar, a phosphate sugar, a phosphate groupgroup, & a , & a basebase

attach to one another to form a ladderattach to one another to form a ladder

The sides of the DNA ladder are made up The sides of the DNA ladder are made up of of phosphatesphosphates & & sugarssugars

The steps or rungs of the ladder are made The steps or rungs of the ladder are made up of 2 up of 2 basesbases

Nucleotide DNANucleotide DNA

The bases in DNA come in The bases in DNA come in 44 types types Adenine (A)Adenine (A) Thymine (T)Thymine (T) Cytosine (C)Cytosine (C) Guanine (G)Guanine (G)

So there are So there are 44 different types different types

of nucleotidesof nucleotides

A A can ONLY go with can ONLY go with TT TT can ONLY go with can ONLY go with AA CC can ONLY go with can ONLY go with GG GG can ONLY go with can ONLY go with CC

The pattern of the The pattern of the basesbases

actually makes up the codeactually makes up the code

in the DNAin the DNA

One section of DNA code codes for One section of DNA code codes for one one protein, which then controls protein, which then controls oneone characteristic characteristic in an organism.in an organism.

How is DNA copied by a cell?How is DNA copied by a cell? DNA has to be copied every time a cell goes DNA has to be copied every time a cell goes

through the through the cell cycle (cell cycle (to make more cells:mitosis)to make more cells:mitosis)

DNA is copied during the DNA is copied during the SS phase of phase of interphaseinterphase It needs to be copied so each new cell has It needs to be copied so each new cell has

identical DNAidentical DNA

1. An 1. An enzymeenzyme attaches to the DNA molecule and attaches to the DNA molecule and starts to starts to unzipunzip or or unwindunwind it. it.

The bond between the The bond between the basesbases is broken is broken

2.2. The bases are exposed! A new The bases are exposed! A new nucleotidenucleotide attaches to the matching nucleotide on the attaches to the matching nucleotide on the

openopen DNA strand. DNA strand. 3. An enzyme 3. An enzyme proofreadsproofreads the DNA & stops the the DNA & stops the process & fixes any mistakes that may occur.process & fixes any mistakes that may occur.

4. In the end, 4. In the end, 22 identical pieces of DNA are made. identical pieces of DNA are made. Each is made of half old & half new DNA.Each is made of half old & half new DNA. Replication

PART 3. DNA to RNA - TranscriptionPART 3. DNA to RNA - Transcription

A.A.DNA is the DNA is the reciperecipe which codes for how to make which codes for how to make all the different types of all the different types of proteinsproteins

DNA can’t make the proteins (It is the recipe)DNA can’t make the proteins (It is the recipe) DNA never leaves the DNA never leaves the nucleusnucleus, & proteins are , & proteins are

made on the made on the ribosomesribosomes

B. Proteins are the building blocks of B. Proteins are the building blocks of lifelife Proteins are necessary to BUILD an Proteins are necessary to BUILD an organismorganism Hair, muscle, bones = made of proteinsHair, muscle, bones = made of proteins Proteins are necessary to make an organism Proteins are necessary to make an organism

functionfunction & be alive & be alive Proteins are made of Proteins are made of amino acids amino acids – the amino – the amino

acids are like the ingredients to make the acids are like the ingredients to make the proteinsproteins

C.C. RNARNA (Ribonucleic acid) is the molecule that (Ribonucleic acid) is the molecule that will help will help build build the proteinsthe proteins

RNA RNA makes the proteins on themakes the proteins on the ribosomes ribosomes, , using the instructions it gets from DNA (It is using the instructions it gets from DNA (It is like a chef following a recipe)like a chef following a recipe)

RNA is very RNA is very similarsimilar to DNA to DNA -Both needed to build proteins-Both needed to build proteins - Both are nucleic acids- Both are nucleic acids -Both are made of nucleotides-Both are made of nucleotides -Both contain a code-Both contain a codeBut RNA is also very But RNA is also very differentdifferent than DNA than DNA

DNADNA RNARNA Sugar = DeoxyriboseSugar = Deoxyribose Job = Controls everything Job = Controls everything

in a cell “recipe”in a cell “recipe” Shape = double strandedShape = double stranded Only 1 typeOnly 1 type

Has Has ThymineThymine as a base as a base

Sugar = RiboseSugar = Ribose Job = Helps to build Job = Helps to build

proteins in a cell “chef”proteins in a cell “chef” Shape = single strandedShape = single stranded 3 types 3 types

mRNA, tRNA & rRNAmRNA, tRNA & rRNA Has Has UracilUracil as a base as a base

RNA comes in RNA comes in 33 different types: different types:1.1. Messenger RNA (mRNA)Messenger RNA (mRNA) Carries a message from DNA to the ribosome for Carries a message from DNA to the ribosome for

how to build a proteinhow to build a protein Made in the Made in the nucleus nucleus & moves to the & moves to the ribosomesribosomes

2. 2. Ribosomal RNA (rRNA)Ribosomal RNA (rRNA) Part of the ribosomePart of the ribosome Help to make Help to make proteinsproteins

3. 3. Transfer RNA (tRNA)Transfer RNA (tRNA) Brings the ingredients (Brings the ingredients (amino acidsamino acids) needed to make ) needed to make

proteinsproteins to the to the ribosomeribosome where they are made where they are made

The 3 different types of RNA The 3 different types of RNA must all work together to must all work together to make make proteinsproteins

Making proteins involves Making proteins involves 2 2 processes: processes:

TranscriptionTranscription & & TranslationTranslation

1. During 1. During TranscriptionTranscription:: mRNA is made in the mRNA is made in the nucleusnucleus using using DNADNA as a as a

guideguide

DNADNA has the recipe for how to make has the recipe for how to make proteinprotein, but , but it is stuck in the it is stuck in the nucleus. mRNAnucleus. mRNA is a copy of is a copy of the recipe that is brought to the the recipe that is brought to the ribosomeribosome (protein factory) to make the (protein factory) to make the protein protein

2. During 2. During Translation:Translation: The mRNA, which is now at the ribosome, is The mRNA, which is now at the ribosome, is

read & translated, so it knows what read & translated, so it knows what amino acids amino acids are needed to be put together to make the are needed to be put together to make the proteinprotein

The The tRNAtRNA brings the needed brings the needed amino acidsamino acids to the to the ribosomeribosome

The ribosome, which is made of The ribosome, which is made of rRNArRNA, attaches , attaches the the amino acidsamino acids into a into a chainchain following the following the directions in the mRNAdirections in the mRNA

A protein is formedA protein is formed Protein synthesis

The chef (ribosome) now has the protein recipe The chef (ribosome) now has the protein recipe (mRNA) (mRNA)

The ingredients need to be brought to the chef. The ingredients need to be brought to the chef. The The tRNAtRNA brings the needed ingredients ( brings the needed ingredients (amino amino acidsacids) to the chef (ribosome)) to the chef (ribosome)

The chef (ribosome) now follows the recipe The chef (ribosome) now follows the recipe ((mRNAmRNA) and attaches the ) and attaches the amino acidsamino acids into a into a chain. A protein is made!chain. A protein is made!

How can we read & translate the mRNA?How can we read & translate the mRNA?1.1. Every Every 3 3 letters in the mRNA codes for an letters in the mRNA codes for an amino acidamino acid

This is called a This is called a codoncodon2. Use a chart to figure out which 2. Use a chart to figure out which amino acidamino acid is needed is needed DNA code:DNA code: mRNA:mRNA: Amino acids needed:Amino acids needed:

ATTATT

GCGGCG

GCCGCC

TAATAA

ATCATC

CGACGA