DNA
Genetic materialThe Hershey-Chase experiments were a series of experiments conducted in 1952 by Alfred Hershey and Martha Chase that helped to confirm that DNA is genetic material. They used a bacterial cell(host) and a bacteriophage with radioactive protein capsule or one with radioactive DNA. After the protein and the radioactive were labeled with sulfur they allowed them to infect the bacterial separately. The result of the protein was no radioactive material inside the pallet it was all in the fluid outside. Anything that was protein outside did not get into the bacterial cells. With the DNA, all the radioactivity is inside the pellet (bacteria) and none was in the fluid outside.
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DNA vs RNAAlthough DNA and RNA both carry genetic information, there are quite a few differences between them.
RNA: RNA is used to transmit genetic information in some organisms and may have been the molecule used to store genetic blueprints in primitive organisms. |
Protein synthesis
![Picture](/uploads/2/4/1/6/24164881/5318858.png?266)
Protein Synthesis occurs in 2 main steps:
- Transcription: transcription is the synthesis of RNA from a DNA template.
- Initiation: An enzyme called RNA polymerase attaches to the template DNA strand and begins to catalyze production of complementary RNA. Specifically, it binds at a sequence of DNA called the promoter.
- Elongation: The covalent addition of nucleotides to the 3' end of the growing polynucleotide chain. It involves the development of a short stretch of DNA that is single-stranded.
- Termination: The recognition of the transcription termination sequence and the release of RNA polymerase.
- mRNA attaches to the ribosome.
- tRNA's attach to free amino acids in the cytoplasmic "pool" of amino acids.
- tRNA carries its specific amino acid to the ribosome.
- tRNA "delivers" its amino acid based on complementary pairing of a triplet code (anticodon) with the triplet code (codon) of the mRNA.
- Enzyme "hooks" the amino acid to the last one in the chain forming a peptide bond.
- Protein chain continues to grow as each tRNA brings in its amino acid and adds it to the chain.
Transcription factors
Although transcription is performed by RNA Polymerase, the enzyme needs other proteins to produce the transcript. These factors are either associated directly with RNA Polymerase or add in building the actual transcription apparatus. The general term for these associated proteins is transciption factor.
Functions of Transcription Factors
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Rna processing (post transciption)
The RNA copy of a protein encoding gene must be modified in several ways before it can be transported out of the nucleus and translated into protein. The primary transcription product of a gene is therefore called a precursor of mRNA, pre-mRNA. It takes place after transcription, before mRNA leaves the nucleus.
Events: 3 steps
Events: 3 steps
- 5’ cap added for protective covering
- Poly-A tail added to 3’ end
- RNA splicing to remove intons AND/OR to create alternative RNA transcripts coding for different protein products.
Point mutations
A point mutation is a type of mutation that causes a single nucleotide base substitution, insertion, or deletion of the genetic material,DNA or RNA. The term frameshift mutation indicates the addition or deletion of a base pair.
Helpful resources
Pictures Cited: http://s.hswstatic.com/gif/genetics-at-work2.jpg
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRVXrm9A3ptH70fLqC1GHk2wxtxcrCVZ727whY9ugTHQDpd8AL3ew
Mr. Caviness pictures
https://apbio-werle.wikispaces.com/file/view/c8.18x8.processing.jpg/68536799/c8.18x8.processing.jpg
https://upload.wikimedia.org/wikipedia/commons/thumb/6/69/Point_mutations-en.png/350px-Point_mutations-en.png
http://study.com/cimages/multimages/16/point_mutation_types.png
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRVXrm9A3ptH70fLqC1GHk2wxtxcrCVZ727whY9ugTHQDpd8AL3ew
Mr. Caviness pictures
https://apbio-werle.wikispaces.com/file/view/c8.18x8.processing.jpg/68536799/c8.18x8.processing.jpg
https://upload.wikimedia.org/wikipedia/commons/thumb/6/69/Point_mutations-en.png/350px-Point_mutations-en.png
http://study.com/cimages/multimages/16/point_mutation_types.png