Be able to describe the structure of RNA Be able to describe the structure of DNA Why is DNA so important DNA carries genetic information It passes on the features of organisms from one generation to the next ID: 920073
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Slide1
Objectives
Be able to describe the structure of a nucleotide
Be able to describe the structure of RNA
Be able to describe the structure of DNA
Slide2Why is DNA so important?DNA carries genetic information
It passes on the features of organisms from one generation to the nextThe code on DNA determines the sequence of amino acids in a protein – the primary structure
Slide3DNA is made up of many nucleotides
Pentose (5 carbon) sugar
The organic base contains nitrogen
Slide4There are 4 different DNA nucleotides, each with a different base- what are the 4 bases?A- adenine
T- thymineG- guanineC-cytosine
Slide5How is a mononucleotide formed?
The pentose sugar, organic base and phosphate group are all joined by condensation reactions to form a
mononucleotide
Slide6A condensation reaction between two nucleotides forms a phosphodiester bond
Phosphate group of one mononucleotide is joined to the deoxyribose group of another in a condensation reaction
Slide7A polynucleotide contains many nucleotides
Slide8Zoom in!
Slide9How did we discover the structure of DNA? http://www.dnaftb.org/19/animation.html
Questions:
What stands out from Chargaff’s findings?
What would be the problem with pairing A-T or C-G?
CLICK THROUGH ANIMATION
Slide10Base pairing The bases on the two strands of DNA attach to each other by hydrogen bonds The hydrogen bonds hold the two strands together Adenine always pairs with thymine
Guanine always pairs with cytosine
Slide11A complementary to TC complementary to G
Slide12Slide13Base pairing (DNA interactive- Animations- Base Pairing)
Hydrogen bonds
Slide14A nucleotide showing the positions of the 3-prime and 5-prime carbon atoms on the pentose sugar
Slide15Antiparallel strands
Slide16The double helix
Look at the model
Slide17Fill in the gaps on the back of your sheet
Slide18Why is DNA so stable?the phosphodiester backbone protects the more chemically reactive organic bases
hydrogen bonds link the base pairs forming bridges. As there are 3 H-bonds between cysteine and guanine, more C-G pairings make the molecule more stable.
Slide19Function of DNAMake a note as we go through
Slide20Separate strands are joined by hydrogen bonds, these are easily broken to allow stands to separate for DNA replication & protein synthesis
Slide21It is extremely large, allowing lots of genetic information to be stored.
Slide22Very stable and can be passed from generation to generation (rarely mutates)
Slide23Bases are protected by the sugar phosphate backbone- prevents corruption by outside chemical or physical forces
Slide24The sequence of DNA bases codes for the primary structure of proteins.
Slide25Base pairing allows DNA to replicate and to transfer information to mRNA
Slide26What is the difference between DNA and RNA?
Slide27Slide28RNAA polymerA single, relatively short polynucleotide chain Pentose sugar is always
ribose Bases are adenine, uracil, guanine and cytosine
Slide29The three types of RNA
Slide30Research task…
mRNA
rRNA
tRNA
Which
bases is it made up of?
Draw/describe the structure
What does
it do?