Nucleic Acids Flashcards
What is the purpose of nucleic acids in biology?
Nucleic acids carry genetic information inside the cell and are responsible for the creation of a large number of specific proteins. THe are made up of repeating subunits called nucleotides which forms the structure of DNA among other things.
What is a nucleotide made up of?
Each nucleotide is made up of a pentose sugar, a phosphate group and an organic nitrogenous base.
What are the 2 types of nitrogenous base pairs that make up DNA structures?
Adenine always pairs with Thiamine
Guanine always pairs with Cytosine
When DNA undergoes transcription and RNA is formed, which base pair is changed?
In RNA Adenine will now pair with Uracil
Guanine still pairs with Cytosine
What are the 2 types of nitrogenous bases that occur in DNA and RNA? What is similar about their structures?
The 2 categories are:
- Purines
Base pairs have 2 rings
Includes Adenine and Guanine - Pyrimidines
Base pairs only have a single ring
Includes Thiamine, Uracil and Cytosine
What type of bond links nucleotides to form structures like DNA and RNA?
Phospodidester linkages.
This involves the phosphate of 1 nucleotide bonding to the sugar of the next nucleotide.
The carbon atoms in the sugar of each nucleotide are number 1” (prime) to 5” (prime). The phosphate is at the 5” end while the OH group of the pentose is at the 3” end.
Where is DNA found in animals?
In the nuclear region of the cells.
List 3 ways RNA is different from DNA
- The 2” carbon of RNA is oxygenated, making the sugar ribose instead of deoxyribose
- RNA is single a single helical structure while DNA is double-stranded and therefore has a double helical structure
- In DNA Adenine pairs with Thiamine while in RNA Adenine pairs with Uracil
Name the 3 major types of RNA and describe their roles
mRNA: Messener RNA forms in the cytosol of cells and is “transcribes” from the DNA template. It can then carry this information to the ribosomes
rRNA: Ribosomal RNA is found in the ribosomes and is responsible for synthesising specif amino acids which will then go on to form proteins.
tRNA: Transfer RNA collects amino acids in the cytosol and takes them to the ribosomes where they will then be incorporated into the proteins
What is the name given to a specific sequence of 3 nucleotides in a strand of DNA which codes for the production of a specific amino acid?
A codon.
Researchers observe that DNA Strand A denatures at a lower temperature than DNA Strand B. Which property of the two strands might determine this result?
Strand A likely has more adenine and thymine bases, while Strand B probably contains more guanines and cytosines.
This property is referred to as GC content. Strands with more G and C bases will denature at a higher temperature, as the three hydrogen bonds between guanine and cytosine form a stronger connection than the two between adenine and thymine.
