DNA and RNA Questions 1.What do the letters DNA stand for? 2.What do the letters RNA stand for? 3.What are the nitrogenous bases that are used to make.

DNA and RNA

Questions1.What do the letters DNA stand for?2.What do the letters RNA stand for?3.What are the nitrogenous bases that

are used to make the DNA molecule?4.What is different between the DNA

and the RNA molecule?

Vocabulary:Transformation bacteriophage

replicationBase pairing Chromatin

DNA polymeraseNucelotide histone

A

CG

T

DNA = DeoxyriboNucleic AcidWhat is it made from?

Nucleotides:Phosphate group

Deoxyribose (5 carbon) sugar

Nitrogen Base

Groups of NucleotidesPurines Pyrimidines

Adenine

Guanine

A

G

Thymine

T

C Cytosine

Chargraff’s Rule1.1.Adenine always bonds with Adenine always bonds with

ThymineThymine

2.2.Guanine always bonds with Guanine always bonds with CytosineCytosine

How do they link up?One Nucleotide links with the next one in the chain by a

COVALENT bonds between the ribose and the next nucleotides phosphate

A

C

The opposite side goes in the other direction, linking across the

nitrogen base by HYDROGEN bonds

G

T

How did we find the structure How did we find the structure of the DNA?of the DNA?In 1953 James Watson and Francis

Crick received the Nobel prize for Science for DNA.

Others were in on the discovery.Another team, led by Rosalind Franklin was working on microscopic X-rays.

A member of her team allowed James Watson to see her work. Shortly thereafter, Watson and Crick published the structure of DNA.

Franklin is not mentioned in the Discovery’s Nobel Prize

Considering the DNA in only ONE Human cell,If you were to type the “A’s, T’s, C’s, & G’s” of the DNA code of one cell it would fill:250,000 pages250,000 pages

Single SpacedSingle Spaced

Arial NarrowArial Narrow fontfont

Front and Back!Front and Back!

So how does all that fit into the cell?

Half inch marginsHalf inch margins

The DNA winds up!The DNA winds up!DNA loose in the cell nucleus The DNA winds up around proteins called HISTONES which help shorten and strengthen the DNA.

The histones continue to wind up into SUPERCOILS

The supercoils wind up into CHROMATIDS (half of a chromosome)

Two chromatids join to form a CHROMOSOME

How do cells make new copies of DNA for new How do cells make new copies of DNA for new cells?cells?Replication:1. When DNA needs to be copied,

it unwinds in the nucleus

2. An enzyme, DNA HelicaseDNA Helicase, starts to “unzip” the DNA making a replication fork.3. As DNA is unzipped, another enzyme, DNA PolymeraseDNA Polymerase, begins to add nucleotides to the now exposed bases of the old strand.

4. The two new DNA strands recoil.

What happens when an error happens?What happens when an error happens?Like this!

G T

DNA Polymerase “proofreadsproofreads” the two new strands of DNA and corrects the error like this.

T

DNA Construction Activity:DNA Construction Activity:http://www.youtube.com/watch?v=q6PP-C4udkA&feature=bf_prev&list=PL7A750281106CD067

http://www.youtube.com/watch?v=yqESR7E4b_8http://www.youtube.com/watch?v=yqESR7E4b_8

Your DNA kit contains 12 black centers, 12 red centers, 3 red straws, 3 blue straws, 3 gray straws, 3 short green straws, 3 white straws, 6 white centers, 24 yellow straws, and the stand 1 four prong center, 1 long gray straw, 3 long green posts.In order to build your DNA strand you will just need:[12]Black Centers = deoxyribose sugar[10]Red Centers = Phosphate[20]Yellow Straws = Covalent bond[6]White Centers = Hydrogen bond[3]Red Straws = adenine[3]Blue Straws = thymine[3]Gray Straws = guanine[3]Green Straws = cytosine

Protein Protein SynthesisSynthesis

1.1. RNA has a sugar riboseRNA has a sugar ribose

DNA has a sugar DNA has a sugar deoxyribosedeoxyribose

2.2. RNA contains the base RNA contains the base uracil (U)uracil (U)

DNA has thymine (T)DNA has thymine (T)

3.3. RNA molecule is single-RNA molecule is single-strandedstranded

DNA is double-strandedDNA is double-stranded

RNA Differs from DNARNA Differs from DNA

DNA “codes” for Proteins,…….. But DNA “codes” for Proteins,…….. But How?How?Transcription:

1. DNA unwinds and unzips.

2. The RNA RNA PolymerasePolymerase attaches to a Initiation site.

4. When reaching a termination site, the RNA Polymerase releases the DNA and goes to make more RNA

3. The RNA Polymerase begins to move only on one (1) of the strands adding RNA nucleotides

A c u a a a g c g u a u g c a

Transcription occurs in the nucleus, but the Messenger RNAMessenger RNA (mRNAmRNA) leaves the nucleus.

It attaches to a RibosomeRibosome which begins to read the mRNA

It reads three (3) letter words called Codons

Example: An mRNA that attaches to the Ribosome

It reads ACU, then it moves down and reads AAA and so on…

Help comes from

anotheranother type of RNA:

tRNA

U G C

A C G

Transfer RNAs have a group of three bases called the “anticodon” that is the compliment of the mRNA

Each TRNA carries a different Amino Acid:

ACG carries Cysteine Cysteine

The process of reading the mRNA code and making Proteins is called:

TranslationThe Ribosome doesn’t just read the mRNA, it calls for Amino Acids for each Codon it reads.

U G C

The codon “U G C” calls for the amino Acid Cysteine.

Hey! I need a Cysteine!! A little help

here?

The Ribosome moves down the mRNA and calls for the next Amino Acid

Cysteine

U G C

Threonine

A C G

U G C A C G

Then the ribosome moves to the next Codon

The first tRNA goes away when the second amino acid is attached to the first with a Peptide bond

Ribosomal RNA (rRNA)Ribosomal RNA (rRNA)

• Made inside the Made inside the nucleus of a cellnucleus of a cell

• Makes up 40% Makes up 40% of Ribosomes of Ribosomes the rest (60%) is the rest (60%) is protein.protein.

At the “STOP” codon, the ribosome releases the mRNA and the Amino Acid Chain.

Proteins ALWAYSALWAYS start with Methionine.

Proteins ALWAYSALWAYS end with stop.

MutationsMutations

• Any change in a DNA sequence Any change in a DNA sequence is a is a mutationmutation

• Mutations that affect Mutations that affect reproductive cells which take reproductive cells which take part in fertilization will become part in fertilization will become part of the altered gene of the part of the altered gene of the offspringoffspring

• Mutations that affect body Mutations that affect body cells are not passed on to cells are not passed on to offspring, but may harm the offspring, but may harm the individualindividual

Types of MutationsTypes of Mutations

1.1. PointPoint – change in one single – change in one single base pair of DNAbase pair of DNA

2.2. Frame shift Frame shift – a single base is – a single base is added or deletedadded or deleted

Deoxyribonucleic Acid (DNA) is the blueprint of life. It contains all the instructions for life’s processes. It’s shape is a twisted ladder, where covalent bonds hold the sides of the ladder together, and hydrogen bonds hold the steps of the ladder together. DNA is composed of individual units known as nucleotides which consist of a phosphate group, a deoxyribose sugar, and a nitrogenous base. Each cell in an organism contains DNA which in turn must be copied and provided to each cell. This process is known as DNA replication. During replication the enzyme DNA Helicase splits the DNA strand by breaking the hydrogen bond between the nitrogen bases causing the DNA to split in two separate parts. Next the enzyme DNA polymerase builds the other side of the DNA strand by attaching corresponding nucleotides to the other side. The nitrogenous bases that hold DNA together are the purines Adenine and Guanine, and the pyrimidines Thymine and Cytosine. Chargraff”s Rule states purines bond with pyrimidines in the specific pairings of Adenine to Thymine and Guanine to Cytosine. These pairings create the double helix structure DNA is known for and the end result of DNA Replication is 2 identical strands of DNA. The function of DNA is to provide coded instructions for building the organism in which it belongs. The building of organisms is called Protein Synthesis. Proteins are composed of amino acids and are the building blocks of all organisms. All things are made of cells, and the mechanical parts of those cells are made of protein. The amino acids used to make specific proteins is in the sequence of three nucleotides known as a codon. There are 20 different amino acids used in the body. The types and order of amino acids determines the particular type of protein made. During protein synthesis RNA polymerase reads the DNA and makes mRNA in a process known as RNA Transcription. The mRNA is then sent to the cytoplasm where it is read and used to attach specific amino acids together to make proteins in a process known as Translation. These proteins are then used to build various cellular structures and molecules within the organism.