Biological Molecules - Structure of DNA and RNA Flashcards
What does DNA do?
Hold or store genetic information
Contains the instructions for the growth and development of all organisms
What does RNA do?
Transfers genetic information from DNA to the ribosomes
What does DNA and RNA have in common?
Both types of nucleic acid
Both found in all living cells
Both needed to build proteins, which are essential for the proper functioning of cells
Both important information-carrying molecules, although their functions are slightly different
What are ribosomes formed from?
RNA and proteins
What are RNA and DNA both polymers of?
Nucleotides
What are the components of a DNA nucleotide?
Deoxyribose
A phosphate group
One of the organic bases adenine, cytosine, guanine or thymine.
What are the components of an RNA nucleotide?
Ribose
A phosphate group
One of the organic bases adenine, cytosine, guanine or uracil.
What is DNA described as?
A double helix
What does condensation reaction between two nucleotides form?
A phosphodiester bond between the phosphate group of one nucleotide and the pentose sugar of the next nucleotide
What are DNA molecules made up of?
Two polynucleotide strands lying side by side, running in opposite directions – the strands are said to be antiparallel
What is each DNA polynucleotide strand is made up of?
Alternating deoxyribose sugars and phosphate groups bonded together to form the sugar-phosphate backbone
These bonds are covalent bonds known as phosphodiester bonds
What is each DNA polynucleotide strand is said to have?
A 3’ end and a 5’ end (these numbers relate to which carbon on the pentose sugar could be bonded with another nucleotide)
As the strands run in opposite directions (they are antiparallel), one is known as the 5’ to 3’ strand and the other is known as the 3’ to 5’ strand
How are the two antiparallel DNA polynucleotide strands that make up the DNA molecule held together?
Hydrogen bonds between the nitrogenous bases
Where do the hydrogen bonds occur between nitrogenous bases?
Adenine (A) always pairs with thymine (T) – two hydrogen bonds
Guanine (G) always pairs with cytosine (C) – three hydrogen bonds
This is known as complementary base pairing
These pairs are known as DNA base pairs
What is a RNA molecule?
A relatively short polynucleotide chain
Single - stranded
