Nucleic acids Flashcards
What are the two main types of nucleic acids?
Deoxyribonucleic acid ( DNA ) and ribonucleic acid ( RNA )
What is DNA?
DNA is the genetic material found in all living other organisms. In eukaryotes, it is found in the nucleus, and prokaryotes, the DNA is not enclosed in a membranous envelope.
What is RNA?
Mostly involved in protein synthesis. The DNA molecules never leave the cell but use an intermediary to communicate with the rest of the cell which is the messenger RNA.
What are the other types of RNA?
rRNA, tRNA, and microRNA are all involved in protein synthesis and its regulation.
What are the monomers of DNA and RNA?
They are known as nucleotides, they combine to form a polynucleotide which are known as DNA and RNA.
What is the basic structure of a nucleotide formed out of?
- a pentose sugar
- a nitrogenous base
- one or more phosphate groups.
What is the sugar in DNA called?
Deoxyribose
What are the features of deoxyribose?
- The pentose sugar is called deoxyribose
- Every DNA nucleotide has the same sugar and phosphate group but the base can vary.
- There are 4 possible bases; adenine ( A ), Thymine ( T ), Cytosine ( C ), and Guanine ( G ).
What is the sugar in RNA called?
Ribose
What are the features of ribose?
They are all the same as DNA but instead of thymine, it is replaced with uracil.
Is DNA double or single-stranded?
DNA is double-stranded whereas RNA is single-stranded.
How do nucleotides form to make a polynucleotide?
- Nucleotides join via a condensation reaction between a phosphate group of one nucleotide and the sugar of another.
- They form a strong, covalent, phosphodiester bond (consisting of the phosphate group and two ester bonds ).
- This chain of sugars and phosphates is called the sugar-phosphate backbone.
- When a polynucleotide is formed, the 5’ phosphate of the incoming nucleotide attaches to the 3’ hydroxyl group at the end of the growing chain.
What is the DNA molecule?
A DNA molecule is a double helix held together by two polynucleotide chains held together by hydrogen bonds and specific complementary base pairs.
What is an RNA molecule?
An RNA molecule is a relatively short polynucleotide chain.
Why did scientists doubt that the DNA carried the genetic code?
As it was relatively simple.
What does the semi-conservative replication of DNA ensure?
It ensures the genetic continuity between generations of cells.
What is semi-conservative replication?
- The method by which DNA replicates, creating two molecules of DNA that consist of one original DNA strand and one newly synthesized DNA strand.
What is the process of semi-conservative replication?
- DNA helicase breaks H bonds between two strands
- Free complementary nucleotides base pair with the exposed strands
- DNA polymerase catalyzes condensation reactions to join adjacent nucleotides, forming phosphodiester bonds.
