Structure Of Dna And Rna Flashcards
Nucleotides are made of three components
A phosphate group
A pentose sugar
A nitrogen containing organic base
In DNA in sugar is
Deoxyribose
In RNA the sugar is
Ribose
Four bases in DNA
Adenine
Thymine
Guanine
Cytosine
Four bases in RNA
Adenine
Uracil
Guanine
Cytosine
Join up by what reaction
Condensation
Two mononucleotides join up to form
A dinucleotide
Bond connecting mononucleotides
phosphodiester bond
Adenine pairs with thymine
2 hydrogen bonds
Cytosine pairs with guanine
3 hydrogen bonds
DNA has a sugar phosphate backbone
Stability and strength
Protecting the bases on the inside from physical / chemical damage
DNA is a very large molecule
Holds lots of information
DNA has a sequence of nitrogen bases
Allows information to be stored
Base sequence codes for polypeptides
DNA is double stranded
Replication occurs semi- conservatively, both strands act as templates
DNA has complementary base paining
Ensures accurate replication takes place - identical copies
Hydrogen bonds between the base pairs in DNA are weak
Enables strand separation/ unzipping so replication can take place
Conservative replication
A separate, entirely new molecule of DNA is built leaving the old molecule intact
Semi-conservative
Each new molecule of DNA has one strand from the original molecule and one new strand
Which enzyme unwinds and unzips the double helix in replication
DNA helicase
DNA replication
DNA unzips
Both strands act as templates
Free DNA nucleotides are attracted to exposed bases on the DNA
Which enzyme joins the nucleotides together along the sugar phosphate backbone in DNA replication
DNA polymerase
What is the name of the bonds formed between adjacent nucleotides in the same strand in DNA replication
Phosphodiester bonds
Three main types of RNA
Messenger RNA (mRNA)
ribosomal RNA (rRNA)
Transfer tRNA (tRNA)
mRNA
Transfers information from DNA to the ribosomes
rRNA
Associated with proteins, rRNA makes up the ribosomes
tRNA
Carries specific amino acids to the ribosomes during protein synthesis
