Chapter 3 - Nucleotides and nucleic acids Flashcards
DNA and RNA are..
polymers
What monomer makes up DNA and RNA
Nucleotides
What are the three components of a nucleotide
- a pentose sugar
- a nitrogen-containing organic base
- a phosphate group
Components of a nucleotide for DNA
o A deoxyribose sugar with hydrogen at the 2’ position
o A phosphate group
o One of four nitrogenous bases - adenine (A), cytosine(C), guanine(G) or thymine(T)
Where is the hydrogen on the DNA nucleotide
2nd position
Nitrogenous Bases in DNA nucleotide
adenine (A), cytosine(C), guanine(G) or thymine(T)
Components of RNA nucleotides
o A ribose sugar with a hydroxyl (OH) group at the 2’ position
o A phosphate group
o One of four nitrogenous bases - adenine (A), cytosine(C), guanine(G) or uracil (U)
What is the function of the hydroxyl group on the 2nd carbon in RNA nucleotide
- makes RNA more susceptible to hydrolysis
- This is why DNA is the storage molecule and RNA is the transport molecule with a shorter molecular lifespan
Draw RNA nucleotide
Draw DNA nucleotide
Define purine
A nitrogenous base that has two rings in their structure that are made up of carbon and nitrogen atoms.
One larger ring is hexagonal while the other smaller ring is pentagonal in structure.
What shape is the larger ring in purines
Hexagonal
What shape is the smaller ring in purines
Pentagonal
What bases are purine
Adenine + guanine
Define pyrimidines
A nitrogenous base that contains only one ring made up of both carbon and nitrogen atoms.
Their ring is also hexagonal.
What bases are pyrimidines
Cytosine
Thymine
Uracil
Flow chart of different structure of nucleotides = visual
Differences between DNA and RNA = sugar/bases/number of strands
How does RNA and DNA form
Condensation reaction
Where does the condensation reaction occur between nucleotides
between the phosphate group of one nucleotide and the pentose sugar of the next nucleotide
What type of bond does the condensation reaction form
Phosphodiester bonds
Draw a polynucleotide
Why is it called a phosphodiester bond
because it consists of a phosphate group and two ester bonds
• The chain of alternating phosphate groups and pentose sugars produced as a result of many phosphodiester bonds is known as….
the sugar-phosphate backbone (of the DNA or RNA molecule)
What do organisms use ATP for
o Anabolic reactions (building larger molecules from smaller molecules)
o Moving substances across the cell membrane or moving substances within the cell
• In animals, energy is also required for:
o Muscle contraction – to coordinate movement at the whole-organism level
o The conduction of nerve impulses
Examples of nucleotides
DNA
RNA
ATP
ATP is a type of..
Nucleic acid
What is ATP specifically
A phosphorylated nucleotide
Structure of ATP
o Three phosphate groups = adenosine triphosphate(ATP)
Adenosine with 1 phosphate group
adenosine monophosphate(AMP)
Adenosine with 2 phosphate groups
adenosine diphosphate(ADP)
What is adenosine
A nucleoside
What is 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 made up of
alternating deoxyribose sugars and phosphate groups bonded together to form the sugar-phosphate backbone.
What are the bonds in the sugar phosphate backbone
Phosphodiester bonds = covalent bonds
Where does the Phosphodiester bond occur
o The phosphodiester bonds link the 5-carbon of one deoxyribose sugar molecule to the phosphate group from the same nucleotide, which is itself linked by another phosphodiester bond to the 3-carbon of the deoxyribose sugar molecule of the next nucleotide in the strand
What does 3’ and 5’ mean
o 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)
o 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 polynucleotide strands held together
Hydrogen bonds between bases