Nucleic Acids (Topic A1.2) Flashcards
(17 cards)
What is DNA?
DNA is the hereditary material of all living things that is passed from parent to offspring and stores genetic information.
A large polymer composed of four different nucleotides
What are the two types of nucleic acids?
Deoxyribonucleic Acid(DNA): A large polymer composed of four different nucleotides
Ribonucleic Acid(RNA): S polymer composed of four different nucleotides
Some viruses use…
RNA as genetic material but they are not living
What are the three different parts of a nucleotide?
- A Pentose Sugar (5 Carbon Atoms)
- A Phosphate Group (Acidic and Negatively Charged)
- One of four nitrogen bases that have either two rings (purine) or one ring (pyrimidine)
Must be able to sketch
What is the backbone of DNA and RNA?
Alternating sugar and phosphates covalently bonded to one another
When a nucleotide is added to a nucleic acid the phosphate on the nucleotide is always linked to the pentose sugar to ensure that there is always an alternating sugar and phosphate
What are the bases of DNA?
DNA contains four nitrogen bases
- Adenine, Guanine, Cytosine and Tymine
What are the bases of RNA?
RNA contains 4 nitrogen bases
- Adenine, Guanine, Cytosine and Uracil
How is RNA formed?
RNA is a single stranded polymer bonded through a condensation reaction. Involving the removal of water and the formation of the covalent bonds with oxygen and the two nucleotides
Should be able to draw and recognize diagrams of the single nucleotides and RNA polymers
What is the shape/structure of DNA?
A double stranded polymer of repeating nucleotides composed of a phosphate group, nitrogen base and deoxyribose sugar.
DNA is also a helical in shape with a constant diameter of 2 nanometers. The double helix allows DNA to could so that it can pack inside the nucleus
What is the use of hydrogen bonds in DNA?
Hydrogen bonds hold together the double stranded polymer using the nitrogenous bases.
Adenine is always bonded to Thymine, having two hydrogen bonds. Guanine is always bonded to Cystine, with three hydrogen bonds. This is known as complimentary base pairing, its always a purine bonded to a pyrimidine, maintaining parallel structure
How do the DNA strands compare to one another?
The strands run antiparallel to one another. One stran begins with a phosphate ground and ends with a sugar and the opposing strand will run in the opposite direction
what are three differences between DNA and RNA?
Double Stranded (DNA) vs Single Stranded (RNA)
Adenine, Cytosine, Guanine and Thymine (DNA) vs Adenine, Cytosine, Guanine and Uracil (RNA)
Deoxyribose Sugar (One fewer oxygen atom) (DNA) vs Ribose Sugar (RNA)
What does complimentary base pairing ensure?
When DNA is replicated the new strand of DNA is identical to the original strand.
What is complimentary base pairing?
Purine adenine always bonds with the pyrimidine thymine and the purine guanine always pairs with the pyrimidine cytosine
It is always a single ring bonded with a double ring.
What is transcription? and how is complimentary base pairing used in transcription?
When a gene is expressed the DNA is copied into RNA during Transcription.
Complimentary base pairing is used in the process but instead of thymine, uracil is the pyrimidine pairing with the adenine
*More on this is DNA replication and Protein Synthesis)
How and why is DNA limitless?
DNA has four different bases which can be put in different sequences, with 4n possible sequences.
DNA is only 2nm, but width of molecules can be any legnth. Huge amounts of information can be stored in very small amount of space and can be tightly packed into the nucleus.
