Download Chapter 12 DNA and RNA - Northwestern High School

Chapter 10 DNA and RNA
10.1 DNA
Deoxyribonucleic Acid
• Experiments
– Griffith –
• MICE!!
• pneumonia
• Determined that some how the harmful strain
infected the harmless
• Discovered Transformation
Oswald Avery
• What caused transformation?
• Different enzymes to try and stop
transformation.
• Deoxyribonuclease , no transformation.
• Taking place in the DNA!!!
Alfred Hershey and Martha Chase
• Studied viruses or bacteriophages. (made
of DNA or RNA and a protein shell)
• Used radioactive markers on the protein
shell and the DNA to see what is
passed…found that genetic material was
in the DNA.
10.2 DNA STRUCTURE
James Watson, Francis Crick, and
Rosalind Franklin
• Discovered the double helix structure.
Structure of DNA
• 3 Main parts of the nucleotide
– Deoxyribose – 5 carbon sugar
– Phosphate
– Nitrogenous base (adenine, guanine, cytosine,
thymine)
• Double Helix
• Chargaff’s rule (base pairing)
– Guanine – cytosine
– Adenine - thymine
• Held together by hydrogen bonds
• Pyrimidine
• Purines
Cytosine
Adenine
Guanine
Thymine
10.3 Chromosomes and DNA
replication
• Prokaryotes – DNA in cytoplasm
• Eukaryotes – DNA in nucleus
– DNA extremely long!!!
• Human DNA actual size is 3 meters long
• Chromosome 13 has a DNA segment 3.2 cm long
DNA Replication
• Use rules of base pairing
– Original = GTTACCATG creates new strand
CAATGGTAC.
• At any point DNA can begin replication
(replication fork)
• Helicases separate the DNA strands.
• Enzyme called DNA polymerase start the
replication
• Semi-conservative – not all of it is new.
• Replicates in both directions until done, read in
only one direction.
Errors in Replication
• Mutation
• Proofreading and repair can prevent this.
10.4 RNA and Protein Synthesis
• Flow of genetic info
• DNA  RNA  Protein
• Transcription  translation  protein
synthesis
• Fig 10-12
• Differences between DNA and RNA
DNA
RNA
Sugar
Deoxyribose
Ribose
Shape
Double stranded
Single Strand
Nitrogenous
Bases
Cytosine – Guanine Cytosine-Guanine
Adenine - Thymine Uracil - Adenine
Types of RNA
• Messenger RNA (mRNA) – carry copies of
instruction from DNA
• Ribosomal RNA (rRNA) – part of
ribosome’s where proteins are assembled.
• Transfer RNA (tRNA) – Transfers each
amino acid to ribosome from codes.
• Transcription
– Starts with RNA polymerase that finds a
promoter on the DNA.
– Separates strand of DNA, makes a copy
(mRNA), then DNA returns to normal
– RNA Editing (pre-mRNA)
• Not all RNA strands are perfect, some have introns
and exons.
• Introns are useless parts, exons are good parts,
introns are removed and exons are pushed
together to form one whole sequence, then
capped.
– mRNA is formed until reaches a terminal
signal
• Genetic code
– Codon - Sets of 3
– UCGCACGGU = UCG CAC GGU =
serine – histidine – glycine
Pg 207
One represents start (methionine , AUG, 3
represents stop)
Translation
• Decoding of mRNA
• Pg 208 (know process, find tRNA, mRNA,
ribosome, nucleus, polypeptide chain,
codon, anticodon.
In your Notes
• Write
TACAATGCTCAAACT
• 1. mRNA Strand to match
• And Decode