Viruses- Invaders that sabotage our cells.
Bacteriophages- Viruses that infect bacterial cells.
Nucleotide- The monomer unit of DNA and RNA which contains a nitrogenous base, 5-carbon sugar, and a Phosphate group.
Sugar-phosphate backbone- formed by covalent bonding between the phosphate of one nucleotide and the sugar of the next nucleotide.
DNA polymerase- adds nucleotides to a growing chain
DNA ligase- joins small fragments into a continuous chain
RNA polymerase- catalyzes reaction
Transcription- Process in which DNA is transcribed in to RNA
Translation- Process in which RNA is transcribed into protein
RNA splicing- removal of introns and joining of exons to produce a continuous coding sequence
Reading Journal:
1) How do viruses work? viruses have genetic material that is surrounded by a protein coat. the proteins bind to receptors on a host's target cell, and the viral nucleic acid enters the cell, which it may choose to remain dormant or activate. Once it is activated, the host cell is destroyed, and the viruses are released to continue.
2) What was the semiconservative model? It is a model for DNA replication. Basically, two DNA strands separate and each strand is used as a pattern to produce a complementary strand. Each DNA helix has one old strand with a new strand.
3)What proteins are involved in DNA replication? DNA polymerase, which adds nucleotides, and DNA ligase which joins small fragments in a continuous chain.
Five Facts:
1) James D. Watson and Francis Crick deduced the secondary structure of DNA.
2) A nucleotide contains a nitrogenous base, a phosphate group, and a 5-carbon sugar.
3) DNA is composed of two polynucleotide chains joined together by hydrogen bonding between bases that is twisted in a helix.
4)DNA replication occurs in a 5' to 3' direction.
5) There are three stages in transcription and translation which include initiation, elongation, and termination.
Viruses are invaders that have the ability to sabotage our cells by destroying and taking over the host cell. Viral proteins are able to bind to receptors on a host's target cell, and once the nucleic acid enters the cell, it will remain dormant. When activated, viral DNA triggers viral duplication, which uses the host's molecules and organelles. Once the host cell is destroyed the, the replicated viruses are released to continue the infection.
Frederick Griffith discovered that "transforming factor" could be transferred in a bacterial cell.
Alfred Hershey and Martha Chase also showed that if they used bacteriophages, it could show that DNA was the genetic material. Bacteriophages are viruses that infect bacterial cells. A nucleotide is a monomer unit of either a DNA or RNA. It contains a phosphate group, a nitrogenous base, and a 5-carbon sugar. DNA and RNA are also polymers called polynucleotides. DNA is composed of two polynucleotide chains that are joined together by hydrogen bonds between bases. Specific base pairings give the helix a uniform shape (A with T, G with C).
In DNA replication, DNA unwinds at the origin, and replication proceeds in both directions from the origin, in a 5' to 3' direction. Replication ends when products form the bubbles merge with each other. Transcription is when DNA is being transcribed to RNA. Transcription has three steps, initiation, which is when RNA polymerase binds to a promoter; Elongation, in which RNA nucleotides are added to the chain. Last is termination, which is when RNA polymerase reaches a terminator sequence and detaches from the template. Translation is when RNA is translated into a protein. Translation has very similar steps as well, and occurs on the surface of a ribosome.
There are three mechanisms which allow the transfer of bacterial DNA: Transformation, Transduction, and Conjugation. Transformation is the uptake of DNA from surrounding environment, while transduction is gene transfer through bacteriophages, and conjugation is the transfer of DNA from a donor to a recipient bacterial cell through cytoplasmic bridge. There are also infectious agents that are made only of RNA or Protein. Viroids, which are circular RNA molecules that infect plants; and Prions, which are infectious proteins that cause brain diseases in animals.
This is an example of an HIV cell, which causes AIDS. The HIV is a retrovirus, containing two copies of its RNA genome and an enzyme that produces DNA from an RNA template, which is called reverse transcriptase. In HIV duplication, the enzymes(Reverse transcriptase) uses RNA to produce one DNA strand, and also produces the complementary DNA strand. The viral DNA enters the nucleus and integrates into the chromosome. This then becomes a provirus, which is used to produce mRNA, which is translated to produce viral proteins. These viral particles are assembled and leave the host cell.
Youtube Overview video of Trascription and Transcription:
http://www.youtube.com/watch?v=XIG_KCAUWPI
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