The structure of nucleic acids Flashcards
What is the structure of DNA?
It is composed of two polynucleotide strands which are wound together to form a double helix structure. It is very long and thin and is tightly coiled within the chromosome.
What pentose sugar is found in DNA?
Deoxyribose
What are the four organic bases in DNA?
Purines – adenine and guanine and pyrimidine – cytosine and thymine.
What forms the sugar phosphate backbone?
And when they talk to you I have a sugar in the phosphate group are found on the outside of the DNA molecule.
What bond is found between the complimentary base pairs?
Hydrogen bonds join the bases together. Adenine and thymine have two hydrogen bonds whereas guanine cytosine has three hydrogen bonds.
What does it mean by the term antiparallel?
It means that they are parallel but are flowing in opposite direction. One goes from the five prime end to the three prime and and the other goes from the three prime end the five prime end.
Is purine in a double or single ring?
Double
Is pyrimidine a double or single ring?
Single
Why is DNA suited to its functions?
As it is a very stable molecules the information is essentially unchanged from generation to generation. As the DNA molecule is large it can carry large amounts of genetic information. The two strands are able to separate due to hydrogen bonds which hold them together and as the base pairs are found inside the double helix the genetic information is protected by the sugar phosphate backbone.
What is the structure of RNA?
It is a single-stranded polynucleotide. It contains the pentose sugar ribose. It contains the pyrimidine bases adenine and guanine and the pyrimidine bases cytosine and uracil.
What are the three types of RNA involved in protein synthesis?
Messenger RNA, ribosomal RNA and transfer RNA.
What is the structure of mRNA?
It is long, single-stranded which forms the helix.
Where is messenger RNA synthesised?
It is synthesised in the nucleus.
What is the function of mRNA?
It carries the genetic code from the DNA to the ribosomes in the cytoplasm.
Why do mRNA molecules vary in length?
They have different lengths related to the genes from which they are synthesised.
