DNA+Review+Period+2

Under each concept term post or revise information to make a fantastic review guide.
 * [[image:dna_image.png width="153" height="46"]] || Why is it called the "Blueprint of Life?" || What is it a blueprint for? || What reads the blueprint? ||

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1. Explain why researchers originally thought protein was the genetic material. Researchers originally thought that protein was the genetic material because protein was a very robust and complex molecule, whereas DNA was just a simple structure composed of A's, T's, G's, a C's. -Joe Illuminati
 * The Molecular Basis of Inheritance**
 * DNA as the Genetic Material**

2. Summarize the experiments performed by the following scientists that provided evidence that DNA is the genetic material: a. Frederick Griffith : Griffith was working to find a cure for pneumonia in 1928 when he discovered the streptococcus bacteria. He mixed a harmless live bacteria with a heat-killed infectious bacteria and put the mixture into the mice. The mice that were exposed to this mixture still died.

b. Oswald Avery, Maclyn McCarty, and Colin MacLeod: They purified both DNA and proteins from pnemonia bacteria in 1944. They injected both the protein and the DNA into the bacteria. When they injected the protein into the bacteria, there was no effect. When they injected DNA into the bacteria, it transformed harmless bacteria into harmful bacteria.

c. Alfred Hershey and Martha Chase: Hershey and Chase were two married scientists, that used the classic blender experiment where they worked with bacteriophage, growing phage viruses in two radioactive substances.. They completed this experiment in 1952 and determined that DNA is the transforming factor, rather than proteins.

d. Erwin Chargaff: Chargraff worked with DNA composition in 1947. He discovered that in natural DNA, the number of cytosine equals the number of guanine while the number of adenine equals the number of thyanine units.

Sam B.

3. Explain how Watson and Crick deduced the structure of DNA and describe the evidence they used. Explain the significance of the research of Rosalind Franklin. Watson and Crick took bits of information collected by other researchers, including the research of Rosalind Franklin. She was a specialist in x-ray crystallography and actually discovered the structure first, though she died before she could publish her findings. The publication told of how genetic instructions are stored in organisms and passed from one generation to another. The specific pairing of nucleotides was one of the basis of they're publication. Crick was also under the influence of LSD when he made the discovery.

[|Watson, Crick & Franklin]

~John Harrison

4. Describe the structure of DNA. Explain the base-pairing rule and describe its significance. DNA Structure - it has a sugar phosphate backbone that protects the bases of A,C,G,T. These are the four nucleotide bases that make every gene and trait. The base pairing rule is where the "A" pairs up with the "T" and "C" with "G". With these bases codes are made that are translated and transcribed to make different proteins, amino acids, etc. - Tim McGinley

5. Describe the process of DNA replication, including the role of the origins of replication and replication forks. Explain the semiconservative replication model.
 * D ﻿ NA Replication and Repair**

6. Explain the role of DNA polymerases in replication. During replication DNA polymerase removes sections of RNA primer and replaces with DNA nucleotides. DNA polymerase can only build on the 3’ or 5’ end of an existing DNA Strand. Ally Zeitz

7. Explain what energy source drives the polymerization of DNA. ATP is the energy source that drives the polyrmerazation in DNA. It works by breaking off a phospaste that the base pair will take, allowing it to bind to its complementary base pair. -Joe Illuminati

8. Define antiparallel and explain why continuous synthesis of both DNA strands is not possible. Antiparallel - In chemistry, it refers to two molecules that run side-by-side, however, they run in opposite directions. (One strand of DNA runs from the 5' carbon while the opposite strand starts from the 3' carbon.

 Because of this, only the leading 5' carbon molecule can be synthesized continuously, while the 3' carbon leading molecule is synthesized in fragments, called the Okazaki Fragments. -Gary C.

Kelsey Brown

9. Distinguish between the leading strand and the lagging strand.

The leading strand is synthesized continously, whereas the lagging strand is synthesized in short fragments that are ultimately stitched together by Okazaki Fragments, the leading strand is synthesized in the same direction as the replication fork while the lagging strand goes the opposite direction. -Muhammad Abdulkafarov

10. Explain how the lagging strand is synthesized even though DNA polymerase can add nucleotides only to the 3 prime end. Describe the significance of Okazaki fragments.

media type="youtube" key="gL3aigv7w4A" height="390" width="640" The lagging strand is synthesized because it is worked on a section at a time. Then RNA primers are laid down and okazaki fragments are built off these RNA primers. The okazaki fragments are added from the 3’-5’ ends each individually connecting to each other, then removing the RNA primes to be replaced with DNA. -Adam A-

11. Explain the roles of DNA ligase, primer, primase, helicase and DNA polymerase. DNA Ligase: Repairs single-stranded discontinuities Primer: what starts the replication process Primase: what adds the primer Helicase: Unwinds the strands of DNA DNA Polyerase: Brings the bases needed to make DNA strands -Zack Miller

12. Describe the structure and function of telomeres. Structure: Guanine-rich six to eight base pair repitition. Function: It prevents the early destruction of the orginal DNA by about 50 copies. This is like the aglet (plastic tip) of a shoe lace. It will eventually no longer exist because it has run out. The gene that controls whether telomeres is active is turned on for the first part of one's life but is shut off after your body no longer needs it. - Tim McGinley



13. Explain the possible significance of telomerase in germ cells and cancerous cells. Telomerase is the like the buffer of DNA when it copies and allows for no damage to be done to the information on the strand. For example, a young child has a lot more telomerase than a 50 year old. If cancerous or germ cells have a lot of telomerase they can continue to multiply and not be damaged or die off. It would be like a cat you didn't want having nine lives so you're stuck with it.

Bailey K.



The Connection Between Genes and Proteins 1. Distinguish between the “one gene one enzyme” hypothesis and the “one gene one polypeptide” hypothesis and explain why the original hypothesis was changed.
 * From Gene to Protein**

2. Explain how RNA differs from DNA. RNA differs from DNA in a few separate ways. First, DNA is a double stranded helix while RNA is a single stranded molecule. The most important difference between the two in simple terms is that DNA holds the information about a specific organism while RNA reads that information. (Think of "D" as Dictionary about you and "R" as the reader). Double Helix >Eric (Terminator) Horrox

3. Briefly explain how information flows from gene to protein.

Information goes from gene to protein through DNA transcription and translation. It starts with DNA in which 3 bases code for one amino acid. The DNA is copied to produce mRNA. The order of amino acids in the polypeptide is determined by the sequence of 3-letter codes in mRNA. Transcription is when DNA is replicated to form a strand of mRNA. Only one strand is copied. RNA polymerase recognizes the promoter and binds to it and starts to copy and unwind DNA. Introns are removed from mRNA. Exons are spliced together. Translation is where ribosomes synthesize proteins using the mature mRNA transcript. TRNA transports amino acid to ribosome. Bonds are moved between the two amino acids. These amino acids connect to form a protein. And that’s how it’s done! Emily Niedrist

4. Distinguish between transcription and translation. Transcription comes before translation. In transcription, the code of DNA is copied into an RNA molecule. In translation, the RNA created from transcription translates the nucleic acid language to amino acid language.

This video demonstrates and explains both transcription and translation. media type="youtube" key="41_Ne5mS2ls?fs=1" height="385" width="480" -John I

5. Compare where transcription and translation occur in prokaryotes and in eukaryotes.

In prokaryotic cells transcription and translation occur simultaneously in the cytoplasm of the organism. In eukaryotic cells, transcriptions occur in the nucleus while translation occurs in the cytoplasm, therefore making it impossible to happen simultaneously. -Adam A-

6. Define codon and explain the relationship between the linear sequence of codons on mRNA and the linear sequence of amino acids in a polypeptide.

A codon is a sequence of nucleotides that contain genetic code for the specific amino acid insertion during protein synthesis. The sequences all determine the spcific action that the protein performs. Any error could result in a serious problem. There are specific start and stop codons that controls the chains. These are very important. Gabby F

7. Explain why polypeptides begin with methionine when they are synthesized.  ﻿Polypeptides begin with methionine because it is the product of the AUG codon. AUG is the start codon for and protein synthesis and it assists the ribosomes assemble within the eukaryotic cells.

*cole j. weber*

 ﻿ ﻿ ﻿ 8. Explain the significance of the reading frame during translation. (reference mutations) One codon on the mRNA codes for one amino acid. If the reading frame shifts, then the mRNA will be read differently adn code for another amino acid. It can cause all of the codons to change during translation, resulting in a completely different protein. Fernanda R.

9. Explain the evolutionary significance of a nearly universal genetic code.

A universal code helps us prove the theory of evolution. This shows that we must have had a common ancestor. We can use this fact because we can find animals that have a genetic make-up that is close to humans and if we want to test a drug, we can test it on them first. Lee C

10. Explain how RNA polymerase recognizes where transcription should begin. Describe the promoter, the terminator, and the transcription unit.
 * The Synthesis and Processing of RNA**

11. Explain the general of transcription, including the three major steps of initiation, elongation, and termination.

12. Explain how RNA is modified after transcription in eukaryotic cells. (Splicing, Introns, and Exons)

After transcription, introns (non coding), leaving the exons (coding).

This shows how after splicing, only exons will remain.

13. Describe the structure and functions of tRNA. A tRNA molecule is a clover shaped, single strand molecule consisting of 70-80 nucleotides. It has loops formed from the base pairing of complementary bases. At the top of the molecule there is an amino acid and at the bottom is an anti-codon. The major function of the tRNA is to translate mRNA sequence into amino acid sequence. The tRNA transfers a specific active amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. tRNA (as well as mRNA and rRNA) is needed in order for protein to be synthesized.
 * The Synthesis of Protein**

~Ryan C.

14. Describe the structure and functions of ribosomes. <span style="color: #1da4cd; font-family: Georgia,serif;">Ribosomes are made of rRNA and proteins. It has two subunits, a large one and a small one. Its job is to translate mRNA and synthesis proteins. They are located on the Rough Endoplasmic Reticulum and in the cytoplasm. <span style="color: #1da4cd; font-family: Georgia,serif;"> <span style="color: #1da4cd; font-family: Georgia,serif;">Picture of a ribosome and Endoplasmic Reticulum <span style="color: #1da4cd; font-family: Georgia,serif;">media type="youtube" key="nl8pSlonmA0?fs=1" height="329" width="444" <span style="color: #1da4cd; font-family: Georgia,serif;">This is a video of the Ribosome translating. <span style="color: #1da4cd; font-family: Georgia,serif;">- Fernanda R.

15. Describe the process of translation (including initiation, elongation, and termination) and explain which enzymes, nucleotides, and energy sources are needed for each stage. translation is the third stage of protein biosynthesis. In translation, messenger rna produced by transcription is decoded by the ribosome to produce a specific amino acid chain, or polypeptide, that will later fold into an active protein. In Bacteria, translation occurs in the cell's cytoplasm, where the large and small subunits of the ribosome are located, and bind to the mRNA. In Eukaryotes, translation occurs across the membrane of the endoplasmic reticulum.The ribosome facilitates decoding by inducing the binding of trna with complementary anitcodon sequences to that of the mRNA. The tRNAs carry specific amino acids that are chained together into a polypeptide as the mRNA passes through and is read by the ribosome.

16. Describe two properties of RNA that allow it to perform so many different functions. The two properties of RNA that allow it to perform different functions are its similar structure to DNA and its ability to aid in the production of proteins. RNAs structure differs from DNA because instead of thymine as a base uracil is. This makes RNA less stable then DNA. RNA can store genetic information and copy it. TRNA, mRNA, and RNA Polymerase all aid in the production of proteins. Bailey K.

17. Compare protein synthesis in prokaryotes and in eukaryotes. Protein synthesis differs in prokaryotes and eukaryotes. However, there are some similarities between the two. The most obvious similarity is that they both are trying to synthesize a protein. They take different amino acids and different codons and try to form a mass of proteins for the cell to use. There are many differences between the two processes also. For example, when the ribosomes play a part in the protein synthesis, the ribosomes in eukaryotes are greater in size than the ribosomes in prokarotes. Another important difference between them is that the proteins don't start with the same amino acid code. The starting amino acid for every eukaryotic cell is methionine which in prokaryotes, its formylmethionine. The last and final difference is that the eukaryotic cell has a nucleus membrane while the prokaryotic cell doesn't not have a membrane. This effects the tRNA and mRNA transfer.

media type="youtube" key="B6O6uRb1D38?fs=1" height="385" width="480"

- CHRIS A.

18. Define point mutations. Distinguish between base-pair substitutions and base-pair insertions. Give examples of each and note the significance of such changes. A point mutation is a type of mutation where a single nucleotide (A, T, C, G, or U) in RNA or DNA is replaced with another. Base-pair substitutions are when a nucleotide is substituted with another Base-pair insertions are when a nucleotide is inserted into a correct DNA or RNA sequence. The newly inserted nucleotide pushes back the following nucleotides thus messing up the whole sequence. Nucleotides are replaced causing a normal hemoglobin cell to turn into a sickle-cell hemoglobin. -Videl S.

19. Describe several examples of mutagens and explain how they cause mutations.

<span style="color: #7f0db9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">A mutagen is something that causes a mutation in our DNA. It can be physical or it can be chemical. For example some physical agents consist of X-Rays, ultraviolet lights, and Gamma Rays. Nitrous acid, bromine, and benzene are some examples of chemical agents. Exposure to these mutagens causes mutations in various ways: <span style="color: #7f0db9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">By messing with the natural flow of DNA replication, these mutagens can cause cancer, result in disease, or result in an increased risk for disease.
 * <span style="color: #7f0db9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">By acting as base analogs and getting placed into DNA during replication
 * <span style="color: #7f0db9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">By reacting with DNA and causing changes that mess up the copying of the strand
 * <span style="color: #7f0db9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">By causing cells to make chemicals that create nasty effects on the DNA

<span style="color: #7f0db9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">

<span style="color: #7f0db9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">Ashley E

1) Describe how DNA technology can have medical applications in such areas as the diagnosis of genetic disease, the development of gene therapy, vaccine production, and the development of pharmaceutical products.
 * General Biotechnology Concepts we’ve discussed**

DNA technology can have medical applications in areas such as diagnosis, therapy, vaccine, and development of pharm. products because of the modern research. We have discovered that DNA is a long, organized classification of genes. By understanding what and how these genes are coded for, we are able to create different medicines personalized for patients with specific conditions/diseases, as well as prepare treatment based on the genetic background of a person. Such experimentation has come a long way since DNA has first been discovered. Gene therapy is possible because DNA has been broken down to the bare bones. We are now able to reconstruct parts of the DNA to yield viable results; scientists are able to restructure the codon sequences to produce desired anticodons, thereby leaving the appropriate proteins to form the desired results. It all revolves are DNA reconstruction and protein production.

Ariel O.

2) Explain how DNA technology could be used in the forensic sciences.

DNA has already begun to be widely used in forensic science. We are able to find blood that is invisible to the naked eye. After we find some blood we can run some test and find out the genetic make-up of that person. If a suspect has that same genetic make-up then we have our killer. DNA helps us identify to exactness who actually committed the crime. Lee C-

3) Describe how gene manipulation has practical applications for environmental and agricultural work. Explain how DNA technology can be used to improve the nutritional value of crops and to develop plants that can produce pharmaceutical products. <span style="color: #00ff00; font-family: 'Courier New',Courier,monospace;">﻿Gene manipulation is becoming more popular among foods because of the wide range of benefits it gives us. Reseachers forsee that soon they will be able to genetically manipulate a tomato that contains a medicine that can help you avoid getting headaches. And the debate comes up often about pesticides having to be sprayed on crops in order to kills insects eating them but soybeans can also be genetically manipulated to be immune to the poisons that are in pesticides so now the insects die but the crops do not.

<span style="color: #00ff00; font-family: 'Courier New',Courier,monospace;">*cole j. weber*

4) Discuss the safety and ethical questions related to recombinant DNA studies and the biotechnology industry.

It is not natural and artificial. It isn't ethical because it isn't natural. You pick what you want in the DNA and choose what you do not want in the DNA. To make recombinant DNA it is engineered. Tyler H.