nucleotides and nucleic acids Flashcards
name the pentose sugar in DNA and RNA
DNA: deoxyribose
RNA: ribose
describe how polynucleotides stands are formed and broken down
condensation reactions between nucleotides form strong phsophodiester bonds (sugar-phosphate backbone)
hydrolysis reactions use a molecule of water to break these bonds
enzymes catalyse these reactions
name the purine bases and describe their structure
adenine
guanine
two-ring carbon structure
name the pyrimidine bases and describe their structure
thymine
cytosine
uracil
one ring-carbon structure
name the complementary base pair in DNA
2 H-bonds between adenine and thymine
3 H bonds between guanine and cytosinen
name the complementary base pairs in RNA
2 H bonds in adenine and uracil
3 H bonds in guanine and cytosine
what are the two types of nucleic acids
DNA
RNA
what is a phosphodiester bond
a phosphate group and 2 ester bonds
what is the bond between 2 nucleotides called
phosphodiester bond
describe the structure of DNA
double stranded
consists of two strands running in opposite directions (anti-parallel)
2 strands held together by hydrogen bonds between complementary bases
complementary base pairing:
- Adenine always binds with Thymine
- Cytosine always binds with Guanine
- a pyrimidine always pairs with a purine
Hydrogen bonds form between deoxyribose molecules causing the 2 DNA strands to coil up into a helix – known as the double helix
Explain how the nucleotides in a DNA molecule are arranged as two polynucleotide strands
phosphodiester bonds in, backbone / described ✔
hydrogen / H, bonds / bonding (between chains / bases) ✔
purine to pyrimidine / A to T and C to G ✔
3 H bonds between C and G
2 H bonds between A and T
nucleotide
pentose sugar (deoxyribose or ribose)
phosphate group (attached to carbon 5)
nitrogenous group (attached to carbon 1)
