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
What is RNA and what is it’s function?
Where does RNA synthesis take place?
Ribonucleic acid- controls the assembly of amino acids into proteins.
Nucleus and cytoplasm for eukaryotes
What are the types and function RNA
- Messenger: carries the message of what amino acids are to be put together in what sequence to make cell proteins.
- Ribosomal: important component of ribosomes
- Transfer: transfers amino acids to the ribosome for assembly in proteins.
Transcription:
Synthesis of an RNA molecule Fromm DNA template, the base sequence of the transcribed RNA complements the base of the template DNA.
Steps of transcription
- DNA is transcribed in small messages to be carried to a ribosome.
- RNA polymerase is used to read by matching DNA code to RNA bases. Starting at the promoter.
- mRNA is transported out of Nucleus.
- Single stranded mRNA finds ribosome in cytoplasm.
Describe translation
- mRNA moves to a ribosome made of rRNA where the protein is assembled.
- tRNA carries amino acids according to its anticodon.
- mRNA holds the codons
- Initiation
- Elongation
- Termination
Codon
Anticodon
Group of 3 nucleotide bases in mRNA that specify a particular amino acid
Sequence of 3 bases that are complementary to codon
Describe Initiation
Binding of mRNA to the small subunit of a ribosome. First tRNA with its amino acid binds to mRNA, large subunit binds so that the first tRNA is in the p side. First codon of mRNA is AUG, first tRNA is TAC= start codon of methionine.
Describe elongation
Binding of second tRNA carrying amino acid to the A side. One tRNA is in place, an enzyme detached the first amino acid. A peptide bond is created between the first and second amino acid. First tRNA is released from p site to go back out to cytoplasm. Second tRNA is moved to p site, keeps going until stop codon.
Describe termination:
When the codon sequence UGA reaches the a site it attracts the protein release factor. The peptide is release from the tRNA. The sun units separate from mRNA.
How many amino acids are there?
20
What’s a tripeptide ?
Peptide with 3 amino acids joined by peptide bond.
What’s a mutation and what are the two types of mutations?
Change in genetic material of a cell
- Gene mutation: produce change in single gene
- Chromosomal: change in whole chromosome
Describe the types of gene mutations
Substitution: a single nucleotide is replaced or substituted, there may be a change of amino acid.
Insertion: a single nucleotide is inserted into the DNA sequence a frameshift occurs and all amino acids after the mutation may be changed.
Deletion: similar to insertion it can change all amino acids after.
Point mutations
Occurs at a single post in the sequence (insertion, deletion)
What are the types of chromosomal mutations:
Deletion: loss of part of all of a chromosome
Duplication: extra copy of all or part of a chromosome
Inversion: reverses direction of parts of a chromosome
Translocation: part of one Chi Rome breaks off and attaches to another.
What’s a mutagen?
Chemical or physical agents that interact with DNA and may cause a mutation.
Chemical: pesticides, tobacco smoke
Physical: some radiation (x rays)
How can mutations be good, how can they be bad?
Dramatically change protein structure ( sickle cell)
Insects can resist pesticides, polyploid plants are larger
What’s gene therapy? How is it being used? What are the two types
Transplantation if normal genes into cells in place of missing or defective one to correct issues.
Used to make cells more resistant to chemotherapy and tumor cells more sensitive.
Ex vivo- cells modified outside of body then transplanted back in
In Vivo- cells treated inside patients body
Recombinant DNA
DNA produced by combining DNA from different sources
Xenotransplantation:
Grafting or transplanting organs or tissues between different species
Clone
Member of a population of genetically identical cells produced from a single cell. Twins are formed from the first two cells splitting.
Transgenic
Examples
Organism that contains genes of other organism
- Bacteria that contain human genes for the productos of insulin. Which can then be harvested.
- Plants with built in pesticides or can grow in salt rich soils
- Gmo
Hybridization
breeding that involved crossing dissimilar individuals to bring together the best traits of both.
Polyploid
Cell that contains more than two paired homologous sets of chromosomes
Often stronger and larger
What are the proteins in hair, muscles, cellular messengers, antibodies, blood, brain and nerves and enzymes?
Alpha keratin Actin myosin Receptor proteins Antibodies Hemoglobin Ion channel proteins Enzymes made of proteins
Biotechnology
Process of manipulating organisms, cells, or molecules to produce specific products.
Plasmid
Small circular piece of DNA located in the cytoplasm of many bacteria
