DNA & RNA Flashcards
Frederick Griffith
-Studied pneumonia
- isolated two different strands of pneumonia from mice and grew them in the lab
-disease Causing strain grew smooth Edges
-harmless Strain grew rough edges.
What were Frederick Griffith’s experiments?
Experiment one: mice injected with disease, causing strain, got pneumonia and died
Experiment two: mice treated with harmless strain did not get sick
Experiment three: heated disease, causing bacteria to kill and injected heat kill bacteria into mice and they died
Experiment four: mixed, he kill disease, causing bacteria injected into and they got pneumonia and died
Conclusion: heat killed bacteria passed disease, causing ability to harmless strain in a process called transformation
Oswald, Avery
-1944
-Determined which molecules was needed for transformation
- made extract from heat, killed bacteria and treated it with enzymes
In Oswald, Avery’s experiment what did the enzymes destroy?
- Proteins, lipids, carbohydrates and transformation still occurred
-Repeated with enzymes that transformation did not occur
-Conclusion, DNA is responsible for transformation
Alfred Hershey and Martha Chase
-1952
-Studied viruses
-Virus that infect bacteria is called bacteriophage and it has DNA and RNA center with DNA coat
What was Hershey and Chase’s experiment?
Grew viruses in radioactive isotopes phosphorus -32 (p^32)
And sulfur -35 (s^35)
If s- 35 found in bacteria, then protein was injected
If p-32 was found in bacteria than DNA was injected
Concluded, genetic material of bacteriophage is DNA not protein
What is DNA made of?
Nucleotides
What are nucleotides consist of?
Deoxyribose (5 carbon sugar)
Phosphate group
Nitrogen base
What are the four bases of DNA
Adenine
Guanine
Cyostine
Thymine
Erwin Charagaff
In 1950 discovered that the percent of guanine (G) is approximately equal to percent of cytosine (C) in any DNA sample
Rosalind Franklin
Used x-rays to produce an image of DNA
James Watson and Francis crick
-Stole Rosalind Franklin‘s image
- Built a model of DNA explaining how it carried information and how it could be copied
What is base pairing?
When hydrogen bonds only formed between certain pairs
What varies from one species to another?
Number of chromosomes
What is a chromatin?
When DNA is wrapped around a protein called histones
What does each strand of DNA have?
Double helix that has all the information needed to make other strands
What do you use to build a new DNA strand?
Base pairing
Prokaryotes
Replication begins at one point and goes in both directions
Eukaryotes
Replication begins at hundreds of locations and goes both ways until complete
What is replication fork
Site where separation and replication occur occurs
Semi conservative
Each new DNA molecule has one old strand, and one new strand
What is the job of DNA polymerase?
Build new strands and proofread
What is helicase
Enzyme that unzip DNA strands by breaking hydrogen bonds between those pairs
Transcription
Process of making RNA based on DNA code
Translation
Using RNA to make functional protein and happens at ribosome
Genes
Coded DNA instructions that control the production of proteins and ultimately traits and they decode genetic messages by copying part of code from DNA to RNA
What are the three main differences between DNA and RNA
- Sugar in RNA is ribose instead of deoxyribose
- RNA is single stranded.
- RNA contains your uracil in place of thymine
What are the three types of RNA?
Messenger RNA
Ribosomal RNA
Transfer RNA
Messenger RNA
One messenger of RNA (mRNA) carries copies of instructions for assembling amino acids into protein
- Created a nucleus based on segment of DNA
- leaves nucleus
Ribosome RNA (rRNA)
Structural component of RNA
Transfer RNA (tRNA)
Carry amino acid to ribosome and match to correct structure in mRNA
What is a codon?
Three base groups in mRNA code for specific amino acid
Where does transcription start?
Promoter region of DNA
Introns
Part of sequence not needed for protein production
Exons
Part of code needed to make proteins
-slice together and cap and tail for functional mRNA
What is the first codon
AUG
Amino acid bind together to form what
Polypeptide; polypeptide folds into protein
What are two major types of mutations?
Point mutation
-affects only one nucleotide
Frame shift mutation
- Affects everything after mutation in sequence
Silent mutation
Mutation that does not change the amino acid
Missense mutation
Point mutation, resulting in a different amino acid than the original sequence
What are the types of frameshift mutations?
Insertion mutation
- 1 or more nucleotides added to sequence in any direction
Deletion mutation
- One or more nucleotides are removed from sequence in any location
What are causes of mutation?
Over breeding
Chemical damage
Radiation
Nutritional
Mistake in DNA replication
Recombination error
