Structure Of RNA And DNA Flashcards
What does RNA stand for?
Ribonucleic acid.
What does DNA stand for?
Deoxyribonucleic acid.
What does DNA carry?
Genetic information.
What is DNA made up of?
Nucleotides.
What are nucleotides made of?
A pentose sugar, a phosphate group and a nitrogen-containing organic base.
What is a pentose sugar?
A sugar with 5 carbon atoms.
What are the 5 organic bases?
Cytosine, guanine, thymine, adenine and uracil.
What reaction are the pentose sugar, phosphate and organic base joined by?
A condensation reaction.
What bond is formed between nucleotides?
A phosphodiester bond.
Where on the nucleotides is the phosphodiester bond formed?
Between the pentose sugar of one mononucleotide and the phosphate molecule on the neighbouring mononucleotide.
What do 2 mononucleotides bonded together make?
A dinucleotide.
What do lots of mononucleotides bonded together form?
A polynucleotide.
What is the structural difference between DNA and proteins?
DNA is a sequence of bases with nucleotides that form a polynucleotide, protein is a sequence of amino acids that form a polypeptide.
What is RNA?
A single, relatively short polynucleotide chain in which the pentose sugar is always ribose.
What are the organic bases in RNA?
Adenine, guanine, cytosine and uracil.
What does RNA do?
Transfers genetic information from DNA to the ribosomes.
What are ribosomes made of?
Proteins and another type of RNA.
What is a third type of RNA involved in?
Protein synthesis.
Who worked out the structure of DNA in 1953?
James Watson and Francis Crick.
How did James and Francis work out the structure of DNA?
By pioneering work by Rosalind Franklin on the x-ray diffraction patterns of DNA.
What is the pentose sugar in DNA?
Deoxyribose.
What are the organic bases in DNA?
Adenine, thymine, guanine and cytosine.
What is DNA made up of?
Two strands of nucleotides (polynucleotides).
What are the 2 strands of polynucleotides in DNA joined by?
Hydrogen bonds between bases.
How is DNA thought of as a ladder?
The phosphate and deoxyribose molecules alternate to form the uprights and the organic bases pair together to form the rungs.
What is specific is the formation of DNA?
Base pairing.
What does adenine pair with in DNA?
Thymine.
What does guanine pair with in DNA?
Cytosine.
What is the word used to describe base pairings?
Complementary.
What quantities are the same in DNA?
The paired bases (adenine and thymine, guanine and cytosine).
What varies form species to species in DNA?
The ratio of adenine and thymine to guanine and cytosine.
What forms the structural backbone of the DNA molecule?
The wounded deoxyribose and phosphate.
What is the shape of DNA?
A double helix.
Why is DNA a stable molecule?
The phosphodiester backbone protects the more chemically reactive organic bases inside the double helix, and hydrogen bonds link the organic base pairs forming rungs between the phosphodiester uprights.
How many hydrogen bonds form between adenine and thymine?
2
How many hydrogen bonds form between guanine and cytosine?
3
What makes DNA more stable and why?
Lots of cytosine-guanine pairings because they form 3 hydrogen bonds.
What also helps to hold the DNA molecule together?
Base stacking.
What is DNA responsible for?
Passing genetic information from cell to cell and generation to generation.
What provides the genetic diversity within living organisms?
The infinite variety of sequences of bases.
What is a benefit of DNAs very stable structure?
It gets passed from generation to generation, meaning mutations are rare as most are repaired.
What is an advantage of strands being joined by hydrogen bonds in DNA?
They can separate during DNA replication and protein synthesis.
What is an advantage of DNA being a large molecule?
It can carry an immense amount of genetic information.
What is an advantage of having the base pairs within the helical cylinder of the deoxyribose-phosphate backbone?
The genetic information is some what protected from being corrupted by outside chemical and physical forces.
What does base pairing lead to?
DNA being able to replicate and to transfer information as mRNA.
What does the function of DNA depend on?
The sequence of base pairs that is possesses.
