DNA Flashcards
What did Frederick Griffith do?
Through experiments with mice he discovered that bacteria are capable of transferring genetic through transformations. Later it was found that DNA was the material communicating the genetic information.
What did Rosalind Franklin do?
Produced x ray pictures of DNA that helped Watson and Crick
What did Frederich Miescher do?
While isolating the chemicals in WBC he isolated a new molecule he called nuclein. This was actually the first DNA isolation.
Barbara McClintock
Showed that chromosomal crossovers happen in corn chromosomes, also learned that x rays can cause translocation, inversion and deletions in corn.
Oswald Avery
Found that dead bacteria could still cause pneumonia when in contact with harmless bacteria. Found the agent of bacteria transformations was DNA
Alfred Hershey and chase
Discovered viral DNA contained information for how to produced more viruses
Chargaff
Found the rule base pairing percentages. Adenine and thymine percentages were almost equal, as was guanine and cytosine. This is because only binds can firm between the correct pairs.
Watson and crick
Proposed chemical structure of DNA; double helix
What does DNA stand for and what does it do?
Deoxyribonucleic acid- Nucleic acid made up of nucleotides joined into long strands of covalent bonds. Carries genetic information and specifies how to make proteins.
What are the 3 components of nucleotides? Specify those for DNA
Also what holds nucleotides
Sugar -Deoxyribose
Phosphate
Nitrogen bases - Adenine, thymine, guanine, cytosine
Connected by strong covalent bonds
Purine vs pyrimidines
Purine- 2 carbon ring :Adenine, guanine
Pyrimidine- 1 carbon ring: Thymine, cytosine
What bond and how many hold the base pairs
Hydrogen bonds
A2T
G3C
Steps of DNA extraction lab and why each step works
- Mash strawberry: Break cell wall
- Extraction liquid: pulls membrane away from DNA and allows DNA to clump away from protein.
- Filter strawberry liquid: remove seeds
- Ethanol: pushed membrane down and DNA up
What is DNA replication
Copying of DNA before mitosis or meiosis; interphase. Results in creation of double set of semi conservative DNA strands.
|
|->One parent and one daughter strand
What are the 4 enzymes in replication and what do they do?
Helicase: unzips by breaking hydrogen bonds
DNA polymerase: builds new DNA strand by reading parents strand and matching nucleotides.
Primase: initiates the entire process and sets a path for polymerase.
Ligase: Glues Okazaki fragments on the lagging strand
What are the steps of DNA replication?
- Origin discovered and the strands is unzipped forming replication fork.
- SSBP binds to each side to prevent re zipping
- Primase formers primer in both sides of parent strand.
- polymerase goes to primer and uses free nucleotides to build used parent code.
- Covalent bonds are formed from sugar and phosphate.
- Polymerase reads 3’-5’ And builds 5’-3’
- Ligase joins fragments on lagging strand. (1000-2000 nucleotides Long)
DNA polymerase has another job besides building what is it?
Proof reading base pairs to correcting mistakes.
Compare DNA and RNA
DNA: -Codes for traits -deoxyribose -two strands -Nucleus -AT GC -1 type RNA: -protein synthesis -Ribonucleic acid -single stranded -Nucleus and cytoplasm -3 types -Uracil