DNA Flashcards
What is a eukaryotic cell?
This is a cell that has a nucleus
What is a prokaryotic cell?
This is a cell that does not have a nucleus
How are the parts of the cell compartmentalised?
They are contained within organelles
What is the central dogma?
1) DNA replication
2) DNA is transcribed into RNA
3) the RNA is translated into a protein
What is the transforming principle?
S cells contain a chemical that is fatal
R cells do not contain this chemical
The chemical in dead S cell bacteria could be transformed into living bacteria to make them deadly- Living R cells are changed to S cells
What is a bacteriophage?
This is a virus that infects bacteria by sticking to bacteria surface and injecting its own genetic material
Which experiment established DNA as genetic material?
Hershey and Chase: 1952 35S proteins 1) protein coats of phages are radioactively labelled 2) phages infect bacteria with GM 3) no radioactivity enters the cell 32P DNA 1) DNA of phases is radioactively labelled 2) phages infect bacteria with GM 3) radioactivity enters the cell
What makes up a nucleotide?
DNA backbone- phosphates and their esters (phosphate)
Carbohydrates- ribose and deoxyribose (sugar)
Organic bases (nucleoside bases)- AGTC (unit)
What is a nucleotide?
Nucleotides form the basic structural unit of nucleic acids such as DNA
What are the bases and are they purines or pyramidines?
Adenine
Guanine
(Purines)
Uracil
Thymine
Cytosine
(Pyramidines)
What is the difference between ribose and deoxyribose?
Deoxyribose contains one less OH group than ribose
At which parts of DNA does it assemble?
DNA is assembled 5’ to 3’ direction
Describe the structure of the double helix of DNA
Phosphates are on the outside
Bases and hydrogen bonding is on the inside
It contains 2 strands which are antiparallel
Are nucleic acids acidic?
No nucleic acids are not acidic
At pH 7, only one in 1000 will have a proton to donate
The phosphate normally exists as an anion
Are DNA bases basic?
No they are not
Bases at pH 7 are neutral
Why does DNA have an overall negative charge?
Phosphates on the backbone will be negatively charged and so DNA has an overall negative charge