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DNA & Protein Synthesis
SOL: BIO 6 f - i
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SOL: BIO 6 f - i The student will investigate and understand common mechanisms of inheritance and protein synthesis. Key concepts include: f) the structure, function, and replication of nucleic acids (DNA and RNA); and g) events involved in the construction of proteins.
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SOL: BIO 6 f - i The student will investigate and understand common mechanisms of inheritance and protein synthesis. Key concepts include: h) use, limitations, and misuse of genetic information; and i) exploration of the impact of DNA technologies.
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History Before the 1940’s scientists didn’t know what material caused inheritance. They suspected it was either DNA or proteins.
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History A series of experiments proved that DNA was the genetic material responsible for inheritance.
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History In 1952, Alfred Hershey and Martha Chase did an experiment using a virus that infects E. coli bacteria. The experiment proved that DNA and not protein is the factor that influences inheritance.
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History Erwin Chargaff discovered the base pairing rules and ratios for different species. Adenine pairs with Thymine Cytosine pairs with Guanine.
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History Rosalind Franklin & Maurice Wilkins had taken the 1st pictures of DNA using X-ray crystallization
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This proved that DNA had a helical shape.
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The Nobel Prize in Medicine 1962
History The Nobel Prize in Medicine 1962 Francis Harry Compton Crick James Dewey Watson Rosalind Franklin (Died of cancer 1958) Maurice Hugh Frederick Wilkins
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Double Helix Watson Crick Wilkins has become a historical footnote and Watson & Crick are remembered as the Fathers of DNA
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DNA O O=P-O N CH2 O C1 C4 C3 C2 Phosphate Group Nitrogenous base
(A, T, G, C) CH2 O C1 C4 C3 C2 5 Sugar (deoxyribose)
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Nitrogen Bases PGA CUT PY 2 types of Nitrogen Bases Purines
Double ring G & A Pyrimidines Single ring C & U & T PGA CUT PY
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DNA - double helix T A P O 1 2 3 4 5 P O 1 2 3 4 5 G C T A
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DNA The genetic code is a sequence of DNA nucleotides in the nucleus of cells.
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DNA DNA is a double-stranded molecule.
The strands are connected by complementary nucleotide pairs (A-T & C-G) like rungs on a ladder. The ladder twists to form a double helix.
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DNA During S stage in interphase, DNA replicates itself.
DNA replication is a semi-conservative process.
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DNA Semi-conservative means that you conserve part of the original structure in the new one. You end up with 2 identical strands of DNA.
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DNA Gene - a segment of DNA that codes for a protein, which in turn codes for a trait (skin tone, eye color, etc.) A gene is a stretch of DNA.
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DNA A mistake in DNA replication is called a mutation.
Many enzymes are involved in finding and repairing mistakes.
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Mutations What causes mutations?
Can occur spontaneously Can be caused by a mutagen Mutagen: An agent, such as a chemical, ultraviolet light, or a radioactive element, that can induce or increase the frequency of mutation in an organism.
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Mutations Some mutations can: Have little to no effect
Be beneficial (produce organisms that are better suited to their environments) Be deleterious (harmful)
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Mutations Types of mutations
Point Mutations or Substitutions: causes the replacement of a single base nucleotide with another nucleotide Missense- code for a different amino acid Nonsense- code for a stop, which can shorten the protein Silent- code for the same amino acid (AA)
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Mutations Example: Sickle Cell Anemia
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Mutations Types of mutations
Frame Shift Mutations: the number of nucleotides inserted or deleted is not a multiple of three, so that every codon beyond the point of insertion or deletion is read incorrectly during translation. Ex.: Crohn’s disease
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Insertion Deletion
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Mutations Types of mutations
Chromosomal Inversions: an entire section of DNA is reversed. Ex.: hemophilia, a bleeding disorder
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DNA Repair A complex system of enzymes, active in the G2 stage of interphase, serves as a back up to repair damaged DNA before it is dispersed into new cells during mitosis.
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RNA O O=P-O N CH2 O C1 C4 C3 C2 Phosphate Group Nitrogenous base
(A, U , G, C ) CH2 O C1 C4 C3 C2 5 Sugar (ribose)
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RNA Function: obtain information from DNA & synthesizes proteins
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3 differences from DNA Single strand instead of double strand
Ribose instead of deoxyribose Uracil instead of thymine
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3 types of RNA Messenger RNA (mRNA)- copies information from DNA for protein synthesis Codon- 3 base pairs that code for a single amino acid. codon
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3 types of RNA 2. Transfer RNA (tRNA)- collects amino acids for protein synthesis Anticodon-a sequence of 3 bases that are complementary base pairs to a codon in the mRNA
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3 types of RNA 3. Ribosomal RNA (rRNA)- combines with proteins to form ribosomes
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Amino Acids Amino acids- the building blocks of protein
At least one kind of tRNA is present for each of the 20 amino acids used in protein synthesis.
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Transcription - mRNA is made from DNA & goes to the ribosome
Translation - Proteins are made from the message on the mRNA
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Transcription In order for cells to make proteins, the DNA code must be transcribed (copied) to mRNA. The mRNA carries the code from the nucleus to the ribosomes.
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Translation At the ribosome, amino acids (AA) are linked together to form specific proteins. The amino acid sequence is directed by the mRNA molecule. Amino acids ribosome
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Make A Protein DNA sequence ATG AAA AAC AAG GTA TAG mRNA sequence
UAC UUU UUG UUC CAU AUC
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Make mRNA mRNA sequence UAC UUU UUG UUC CAU AUC tRNA sequence
AUG AAA AAC AAG GUA UAG
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Make mRNA mRNA sequence UAC UUU UUG UUC CAU AUC Amino Acid sequence
Tyr Phe Leu Phe His lle
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Human Genome Project The Human Genome Project is a collaborative effort of scientists around the world to map the entire gene sequence of organisms. This information will be useful in detection, prevention, and treatment of many genetic diseases.
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DNA Technologies DNA technologies allow scientists to identify, study, and modify genes. Forensic identification is an example of the application of DNA technology.
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Gene Therapy Gene therapy is a technique for correcting defective genes responsible for disease development. Possible cures for: diabetes cardiovascular disease cystic fibrosis Alzheimer's Parkinson’s and many other diseases is possible.
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Genetic Engineering The human manipulation of the genetic material of a cell. Recombinant DNA- Genetically engineered DNA prepared by splicing genes from one species into the cells of a different species. Such DNA becomes part of the host's genetic makeup and is replicated.
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Genetic Engineering Genetic engineering techniques are used in a variety of industries, in agriculture, in basic research, and in medicine. This genetically engineered cow resists infections of the udders and can help to increase dairy production.
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Genetic Engineering There is great potential for the development of useful products through genetic engineering EX., human growth hormone, insulin, and pest- and disease-resistant fruits and vegetables Seedless watermelons are genetically engineered
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Genetic Engineering We can now grow new body parts and soon donating blood will be a thing of the past, but will we go too far? Photo of a mouse growing a "human ear"
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