Term
| What was work done on fruit flies supposed to help with? |
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Definition
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Term
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Definition
| Individual units of chromatin that consist of protein and DNA |
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Term
| What are two things that chromosomes consist of? |
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Definition
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Term
| How many different amino acids in proteins? |
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Definition
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Term
| how many nucleotides are in DNA? |
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Definition
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Term
| What is the Griffith experiment, and what does it represent? |
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Definition
Looked at a strain of bacterial pneumonia
one strain had smooth coat, S strain, and was pathogenic. The other strain was rough, R strain, and was non-pathogenic. Tested on mice and found S died and R lived. Then heated the bacteria and heat-killed S cells kept the mice alive. He then mixed heat-killed S cells and alive R cells but mice died. R cells picked up S cell phenotypes. Transforming substance=genetic material |
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Term
| What are the 4 nucleotides in DNA? |
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Definition
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Term
| What is the Avery experiment? |
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Definition
| more elaborate version of griffith experiment. Look at bacterial cell morphology, so no longer needed mice. Took away all proteins, lipids, carbohydrates, and RNA from heat-killed S cells. All that was left was DNA. DNA Transforms R cells. Conclusion DNA= genetic material |
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Term
| What is the genetic material? |
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Definition
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Term
| What is the Hershey-Chase Experiment, and what does it represent? |
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Definition
Represents what the genetic material is.
Used distinctive radioactive labeling of protein and DNA in bactriophages. Labeled virus with P and S to determine if protein or DNA was cause. They then allowed viruses to infect cells. Tun through a blender and separated through centrifugation. Materials separated on density, and looked at which were radioactive. 35S was found in supernatan and not in cell pellet (protein did not enter cell). 32P was found in cell pellet and not in supernatant (DNA entered the cell)
Conclusion: DNA=Genetic Material transferred by viruses into cells |
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Term
| What is a bacteriophage? (phage) |
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Definition
Viruses that infect bacteria
Made up of DNA and protein
Transfer genetic matterial into cells while coat remains outsid |
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Term
| What is the Structre of DNA? |
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Definition
Linear polymer of nucleotides
4 different possible nitrogenous bases
5" side=has phosphorus
3" side=no phosphorus |
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Term
| What is Edwin Chargaffs discovery? (Chargaff's Rules) |
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Definition
The base composition of SNA (%, As, Ts, Gs, Cs) differs from species to species, but it is constant within the cells of a species
purines= 50%=pyrimidines
%A=%T
%G=%C
DNA for a given species had specific # but varied among species |
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Term
| What did Rosalind Franklin and Maurice Wilkins do? |
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Definition
Used X-ray diffraction to find out:
DNA=helical
DNA=double stranded
Phosphates are on outside
Aproximate measurement |
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Term
| What did Watson and Crick establish? |
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Definition
Made models and tried to fit Chargoffs rules and franklins results.
- With phophates and sugars on outside, bases point in and have to interact to produce a molecule with the correct diameter
- A-T and G-C can hydrogen bond (Chargaff) with correct total strand diameter (Franklin)
- Able to establish DNA structure
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Term
| What are the implications of watson and cricks DNA structure? |
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Definition
Linear order of 4 possible nitrogenous bases provides mechanism for information content and storage.
Double stranded structure would allow strands to separate and for each to serve as template to make a replica of the other mechanism for copying information |
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Term
| How long is the dna in a cell? |
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Definition
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Term
| What are Dna wrapped around? |
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Definition
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Term
| Where are phosphates and sugars located on the DNA structure? |
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Definition
| on the outside, bases point in |
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Term
| When can you visualize and distinguish chromosomes? |
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Definition
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Term
| Describe the DNA structure that Watson and Crick came up with |
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Definition
DNA is right-handed double helix
Strands are anti-parallel (opposite directions)
Bases in, sugars and phosphates out
C/T and A/T form opposite strands pair
10.5 bases per turn |
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Term
| What are the three possible models for DNA replication? |
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Definition
- Conservative model- start with double stranded dna, make a new strand and conserves orinal piece
- Dispersive model- start with orignal, splits DNA with parts randomly order
- Semiconservative model- start with original, half is old, half is new
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Term
| What is the actual model for DNA Replication and how did they do that? |
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Definition
Semi-conservative model
They cultured bacteria in a medium with N isotope, transfered, and centrifuged, looked at DNA sample. Then repeated.
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Term
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Definition
| material in the chromosomes. Protein, RNA, DNA |
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Term
| What are 4 parts of DNA structure? |
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Definition
Polymer
Double stranded
complementary bases
anti-parallel |
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