Download File - Science with Snyder

Standard 4.1
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.
– RNA, Proteins, and DNA
• Look at names of the enzymes!! Pg 194
• 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.
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
– Double ringed
– Single ringed
Cytosine
Adenine
Guanine
Thymine
• Chromosome vs. gene vs. DNA
Chromosomes and DNA replication
• Prokaryotes – DNA in cytoplasm
• Eukaryotes – DNA in nucleus
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.
DNA functions as the code of life
and the blueprint for proteins.
• Our cells make copies (RNA) of a specific
section of DNA to make specific proteins
we need to live.
• Each type of cell has a different purpose
and plan for protein making.
– Skin makes pigment, oils, and collegen
– Liver cells make catalyse
RNA and Protein Synthesis
• Flow of genetic info
• DNA  RNA  Protein
• Transcription  translation  protein
synthesis
• 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
Gene Linkage
Gene Map
Crossing Over
Incomplete Dominance
Codominance
Multiple Alleles
Polygeneic Traits
Sex-Linked Traits
Pedigree
In your Notes
• Write
TACAATGCTCAAACT
• 1. mRNA Strand to match
• And Decode
•
•
•
•
Replace 3rd A with a C
Now Transcribe and translate again.
What happened?
What type of mutation?
Write same DNA sequence again
• Now insert a T after the 2nd T in the DNA
strand
• What does that do to the amino acids
produced?
• What type of mutation is this?
Mutations
• Check out some mutagens....and what
they do!
Mutagens
Somatic cells
• Cancer cells
Mutations
• Gene mutations – single gene
– Point mutation is a mistake on just one nucleotide
– Nucleotides can be deleted or inserted (pg 307)
• Frameshift mutation
This is an example of
sickle cell:
Substitution
• Lets look at Genetic Disorders
Chromosomal Mutations
• Changes in the number or structure of
chromosomes. (locations of genes, number of
copies of genes)
– Deletion
– Duplication
– Inversion
– Translocation
– Nondisjunction (too few or too many chromosomes
– Not all are bad Delta 32!!
Non -disjunction
Genetic Engineering
• Human
• Genome
• Project
Cloning
Gene
therapy
Selective Breeding
Hybrids