3.A

3.A DNA, RNA and Genetics 

3.A.1

1. James Watson and Francis Crick used Muric Wilkins and Rosalind Franklin's crystallography data and X-Ray diffraction to create the first DNA model. 
2. The Avery, McLeod, and McCarthy experiments were based off of Fredrick Griffiths discovery of a transforming factor in bacteria. What these scientist did was that they provided further evidence by disproving that RNA and protein was not the transforming factor 
3. The Hershey and Chase Experiments used phage which injected DNA into a cell. In the first part of the experiment they put the phage with radioactive amino acids, but the DNA was remained the same. When the phage injected the DNA, the phage that were produced were not radioactive. In the second part of the experiment, the DNA was radioactive and what they found was the DNA, not protein is what carries genetic information.
4. Genetic information is stored and carried through DNA and in some cases RNA.
5.  Noneukaryotic organisms have circular chromosomes while eukaryotic organism have multiple linear chromosomes 
6. A plasmid is a small extra chromosomal double stranded circular DNA molecule.
7. DNA Replication, 

1.  

• Replication: Initiation See above, binds to the promoter region and helps with the transcription factors 
• The transcription factors bind to a region within the promoter called the TATA box 
• RNA polymerase binds to the promoter, forming an initiation complex.

• A regulator protein can sometimes bind just upstream from the promoter in the regulator region, activating the initiation complex.
• Activators proteins bind the the enchanter region 
• Transcription begins 

• Elongation: 
• The RNA polymerase continues to move down the DNA while it continues to untwist the helix and exposes the DNA bases to pair with RNA nucleotides 
• RNA polymerase reads DNA in 3>5 while mRNA is assembled in the 5>3 direction 

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Termination: the mRNA transcript is released when polymerase reaches the termination site. 

Translation: Occurs in the Ribosome, RNA synthesis of a polypeptide (protein)

• The first site enters the ribosome at the P site to initiate translation 
• Another tRNA brings the next amino acid into the A site of the ribosome.
• A peptide bond forms between the two amino acids. the tRNA then removes the A site to P site and ribosome moves over one codon.

Translation: Elongation

• Amino Acids are added one by one to the preceding amino acid chain
• The amino acid is transferred to the growing peptide chain
• The process continues along until the mRNA until a stop codon is reached

1. Retroviruses is a special case and has an alternate flow of information, instead viral genome RNA into DNA. 
2. DNA and RNA both contain three components sugar, phosphate and nitrogenous base. Differences between the two is that DNA contain deoxyribose while RNA contains ribose, RNA also contains uracil in lieu of thymine in DNA. DNA is also double stranded while RNA is single stranded.
3. In Prokaryotes, Since they do not contain a nucleus, the whole process of translation occurs inside of the cell instantaneously.
4. mRNA when it leaves the nucleus, it is tagged by proteins that directed towards the cytoplasm and into the cytoplasms.
5. There are many ways that DNA can be manipulated for human usage including electrophoresis, plasmid based transformation, restriction enzyme analysis and polymerase chain reaction In electrophoresis, electric currents separate DNA fragment that have been cut by restriction enzyme. Restriction enzymes cut DNA at specific nucleotide sequences called restriction sites. Different sizes will move at different speeds through the gel, the smaller fragments will go farther hill the larger ones will stay by the DNA start period. Then DNA fragments can be compared using markers, DNA fragments of known sizes. Plasmid based Transformation is when a cell is altered using foreign DNA.  Cell can be altered to be made into antibiotics and other commercial uses.  Restriction enzyme analysis of DNA is using DNA electrophoresis to identify patterns. Polymerase Chain Reaction (PCR) is a technique to amplify quantities of DNA. PCR uses a thermocycler which can make billions of copies of DNA.
6. Genetically modified foods (GMOs) were commercially began selling in 1994. GM food have been engineered for faster growth, resistance to pathogens, production of extra nutrients and other purposes Transgenic animals are animals that have foreign DNA incorporated into their genome. Mice are used to express human diseases for medical research, products such as insulin and possibly human.  Cloned animals is when scientists use nuclear transplantation and put the nucleus of an unfertilized egg cell and replace it with a nucleus of a differentiated cell.  Pharmaceuticals are used to Recombinant DNA technology to modify E.coli bacteria to produce human insulin and Factor X

3.A.2

1. The first step of Interphase which has period of growth, synthesis of DNA and preparation of mitosis (G1,S,G2 and M) G1 is when the cell grows and functions normally, S is DNA replication and G2 is when the cell continues to grow for mitosis.
2. The checkpoints in the cell cycle are G1, G2, and M. G1 decides whether the cell divides, deals devision or enter a resting stage (G0). The G2 checkpoint determines if the DNA has been replicated and decides if the cell is ready for mitosis. The M checkpoint determines if the chromosomes are alined correctly at metaphase. 
3. The purpose of the Mitosis Promoting Factor (MPF) is a to allow the cell to go to different levels of mitosis once enough MPF has  accumulated in the body. 
4. The platelet derived growth factor (PDGF) is a protein in the cell cycle that binds to a PDGF receptor and activates it. The PDGF is a receptor tyrosine kinase.
5. Cancer occurs in a cell from disruptions in the cell cycle control.
6. Cyclin during interphase accumulates during the cell and cyclin will bind to CaK to form the MPF, when there is enough MPF, G2 ends and mitosis begins. The MPF will then degrade the cyclin and the process repeats
7. The relationship between mitosis and interphase is that a cell is usually in interphase for 95% of its life growing and preparing for mitosis which is where the actual cell division occurs and accumulates 5% of cell life.
8. The key points of mitosis is  prophase, metaphase, anaphase, tele-phase and cytokenesis . In prophase, the nucleus breaks down into chromosomes centriols and other materials. Metaphase is when the chromosomes begin to line up in the middle of the cell. Anaphase is when the centriols and spindle fibers on the opposite side of the cell split apart the cell. Telephase is when the two cells begin to form. And finally cytokenesis is when there are two cells.
9. Meiosis consists of Meiosis, PMAT one, Meiosis 2 and PMAT 2. Everything in the cell occurs just like it would in mitosis EXCEPT in prophase 1, the homologous chromosomes cross over with each other and exchange a piece of their chromosome. Once the end of Meiosis 1 has occurred you have 2 haploid cells (1n). And the PMAT 2 creates 4 (1n) cells.
10. Meiosis creates genetic variation because during meiosis chromatids exchange genetic material via crossing over and creates a cell that is different from the two diploid cells.

3.A.3 

1.  The addition rule however involves the punette square and you add up the amount of genotypes each variation can produce.
2. The law of segregation states that allele pairs separate or segregate during gamete formation
3. The law of Independent assortment states that allele pairs separate independently during the gamete formation 
4. These laws both result in genetic variation because if the two allele pairs separate and then separate independently, then the gamete formed has alleles from both parents and create a new variation of genes.
5. A example of a genetic disorder is Huntington disease. This  is the result of the autosomal dominant disorder that causes degeneration of the nervous system.
6. A example of a chromosomal disorder is Down syndrome. Down syndrome is the result of the Trisomy 21 chromosome having nondisjunction.
7.  Nondisjunction is  when the chromosomes do not separate correctly during meiosis and result in genetic and chromosomal disorders.
8. There are ethical, social and medical issues surround human genetic disorders because people may not believe in knowing what your genetic disorders are. Socially, people may discriminate you due to you have something wrong with your genetics. And the medical issues surrounding human disorders is that it is very expensive and time consuming to help these people who have these genetic disorders.

3.A.4

1. Mendels law do not apply to all traits because these genes (patterns of inheritance) do not follow mendel's laws
2. Sex linked traits are traits that are on sex chromosomes and they can effect males more because Y chromosomes carry little genetic information and males only have on X gene.
3. Nonnuclear inheritance are traits that are not found in the nucleus. Plants have Chloroplast and animals have mitochondria and these traits are determined by cpDNA and mtDNA