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Flashcards in DNA Deck (45)
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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



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
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



Steps of DNA extraction lab and why each step works

1. Mash strawberry: Break cell wall
2. Extraction liquid: pulls membrane away from DNA and allows DNA to clump away from protein.
3.Filter strawberry liquid: remove seeds
4. 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?

1. Origin discovered and the strands is unzipped forming replication fork.
2. SSBP binds to each side to prevent re zipping
3. Primase formers primer in both sides of parent strand.
4. polymerase goes to primer and uses free nucleotides to build used parent code.
5. Covalent bonds are formed from sugar and phosphate.
6. Polymerase reads 3’-5’ And builds 5’-3’
7. 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

-Codes for traits
-two strands
-1 type
-protein synthesis
-Ribonucleic acid
-single stranded
-Nucleus and cytoplasm
-3 types


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.



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

1. DNA is transcribed in small messages to be carried to a ribosome.
2. RNA polymerase is used to read by matching DNA code to RNA bases. Starting at the promoter.
3. mRNA is transported out of Nucleus.
4. Single stranded mRNA finds ribosome in cytoplasm.


Describe translation

1.mRNA moves to a ribosome made of rRNA where the protein is assembled.
2. tRNA carries amino acids according to its anticodon.
3. mRNA holds the codons
4. Initiation
5. Elongation
6. Termination




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?



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

1. Gene mutation: produce change in single gene
2. 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



Grafting or transplanting organs or tissues between different species



Member of a population of genetically identical cells produced from a single cell. Twins are formed from the first two cells splitting.




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



breeding that involved crossing dissimilar individuals to bring together the best traits of both.



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
Ion channel proteins
Enzymes made of proteins



Process of manipulating organisms, cells, or molecules to produce specific products.



Small circular piece of DNA located in the cytoplasm of many bacteria