Core component 5 - DNA and RNA Flashcards
What is a nucleotide made up of?
A phosphate group, a pentose sugar and a nitrogenous base
What are the pyrimidine bases called?
Thymine, cytosine, uracil
What are the purine bases called?
Adenine and guanine
What are the four bases found in DNA?
Adenine -> Thymine
Guanine -> Cytosine
What makes up the backbone of DNA?
The deoxyribose sugar and phosphate groups on the outside
What is the structure of DNA?
It is comprised of two polynucleotide strands wound around each other in a double helix, the strands are antiparallel and there are hydrogen bonds between complementary base pairs maintaining shape.
How many hydrogen bonds between A and T?
2
How many hydrogen bonds between C and G?
3
How is DNA suited to its function?
1) Very stable - information passes essentially unchanged from generation to generation
2) Large - carries large amount of info
3) Two strands can separate
4) Base pairs on inside - genetic info is protected
How does in RNA differ to DNA?
1) Bases in RNA are Adenine -> uracil and Guanine -> cytosine so there is no thymine
2) It is a single-stranded polynucleotide rather than double stranded
3) Pentose sugars are different: RNA - ribose and DNA - deoxyribose
Compare structure of mRNA, tRNA and rRNA
1) mRNA is long (shorter than DNA)
2) rRNA AND tRNA are shorter than mRNA
3) tRNA folds so there are complementary base pairs in some places. Carries a sequence of three bases called the anticodon.
What is the function of tRNA?
Transports amino acids to the ribosomes in protein synthesis
What is the function of rRNA?
Makes ribosomes - site of translation of the genetic code into protein
What is the function of mRNA?
Carries genetic code from the DNA to the ribosomes in the cytoplasm.
Why is DNA transcribed to RNA to be taken out the nucleus?
Chromosomes are too large to fit through the nuclear pores
