Nucleic Acids

What are the components of nucleotides?

-Pentose sugar

-phosphate group

-Nitrogenous base

When is a sugar phosphate backbone created?

When the phosphate group on the 5’ of one nucleotide bonds to a on the 3’ end of another pentose sugar through phosphodiester bonds

What are the 2 types of Nitrogenous bases and what bases do they contain? What is the difference between the tow types?

-Purines: Thymine & Cytosine & Uracil

-Pyrimidines: Adenine & Guanine

Difference: purines have a double ring structure while pyrimidines have a single ring structure

How are 2 DNA strands connected?

Hydrogen bonds form between the nitrogenous bases

What is the role of Complementary Base pairing?

Complementary base pairing reduce the risk of mutations during DNA replication and stabilizes the double helix. It is also used in gene expression through switching certain proteins on and off.

What does Conservative Genetic Code mean? What Theory does this give evidence for?

It means that the genetic code can be translated by all organisms as we all have the same nitrogenous bases.

Gives evidence for Last Universal Common Ancestor

Why is the Directionality of DNA & RNA important?

Nitrogenous bases are read from 5’ to 3’, allowing for the accurate conservation of genetic information through biological processes.

What role does the Purines & Pyrimidines play in the double helix?

Since Purines and Pyrimidines can only bond to one another, they stabilise the double helix as the length of the DNA strand is always the same.

What is a Nucleosome? What purpose do they serve?

Consists of DNA supercooled around 8 histone proteins and are connected to one another via linker DNA.

They protect the DNA and allow a large amount of DNA to fit inside the nucleus

Describe the Herschey & Chase Experiment.

They aimed to see whether proteins or DNA was the genetic material/ they did this by infecting a virus with either radioactive phosphorus (only infects DNA) and radioactive sulphur (only infects proteins). They then inserted these viruses into bacteria and spun the bacteria in a centriphuge to separate the bacteria from the virus. They found that only the phosphate infected bacteria still carried the radioactive phosphorus proving that DNA is the genetic material.

What is Chargaffs Data?

There are an equal number of Adenine to Thymine & Guanine to Cystosine.

Explain "DNA is the genetic material for all life".

- DNA contains all the genetic material of an organism and consists of multiple nucleotides joined by a condensation reaction called polymerisation