Nucleotides Flashcards
What are nucleotides?
Nucleotides are biological molecules that are used in almost all biochemical reactions
What is a nucleotide made of?
Phosphate, nitrogenous base and pentose sugar
Is DNA a double or single helix structure? ——-
Double
Is RNA a double or single helix structure?
Single
What is the monomer for DNA and RNA?
Nucleotides
What are nucleotides used for?
Monomers for DNA and RNA
Regulate metabolic pathways
Component of enzymes like NADP on respiration, NAD and FAD and conenzyme A used in respiration
Where is the DNA in a eukaryotic cell?
Nucleus wrapped in histone proteins
Where is the DNA in a prokaryotic cell?
‘Naked’ in the cytoplasm or in loops
What is DNA?
It is the genetic material containing coded information for the synthesis of proteins
What are the 2 types of bases?
pyrimidines
purines
What is the difference between pyrimidines and purines?
pyrimidines are a single ring structure
purines are a double ring structure
Which bases are purines?
Adenine
Guanine
Which bases are pyrimidines?
Thymine
Cytosine
Uracil - in RNA
How do 2 nucleotides join?
The sugar and phosphate group join at either the sugars 3rd or 5th carbon with a sugar phosphate or phosphodiester bond.
It is a covalent bond.
What shape does DNA make?
A double helix that runs anti-parallel from each other
What is the complementary base pair for adenine in DNA?
Thymine
What is the complementary base pair for guanine?
Cytosine
What is the complementary base pair for adenine in RNA?
Uracil
What holds the 2 helixes together?
Hydrogen bonds
How many H bonds do adenine and thymine make?
2
How many H bonds do guanine and cytosine make?
3
Other than the nucleus where else it their DNA in a eukaryotic cell?
The mitochondria and chloroplasts
What are the 2 strands called?
Leading or lagging strand
What does a 3” strand mean? ——
The phosphate is bonded to the 3rd carbon
What does a 5” strand mean?
The phosphate is bonded to the 5th carbon
What enzyme unwinds DNA?
gyrase
What enzyme unzips DNA?
DNA helicase
What happens when the DNA unzips?
The hydrogen bonds break between the nucleotides, leaving them exposed, so that free phosphorylated nucleotides can bond with their complementary base parings.
What happens on the leading strand?
RNA is placed at the end and then DNA polymerase catalyses the addition of the new nucleotides, going in the 5 to 3 direction, on the leading strand
What happens on the lagging strand?
Because DNA polymerase only goes in from 5 to 3 the RNA polymerase is added at multiple places on the strand, so it adds onto the strand at multiple intervals
How do the individual nucleotides and sugars join to each other?
The nucleotides releases phosphate group and energy to make the phosphodiester bond between the sugar and phosphate group
Which is the lagging strand?
3” - 5”
Which is the leading strand?
5” - 3”
What is conservative replication?
When the DNA double helix is copied as a whole to make 1 new and 2 parental DNA molecule
What is semi - conservative replication?
When the DNA strand unzips and 2 hybrid DNA strands are made
How does DNA replicate in prokaryotes?
A bubble sprouts from the loop, which unwinds and unzips the complementary nucleotides join to the exposed nucleotides until it is all copied
