1.5 Nucleic acids are important information - carrying molecules ( Biological molecules ) Flashcards
Describe the basic functions of DNA and RNA in all living cells
DNA = holds genetic information which codes for polypeptides
RNA = transfers genetic information from DNA to ribosome
name the two types of molecule from which a ribosome is made
RNA and proteins
describe the differences between a DNA nucleotide and an RNA nucleotide
DNA :
- pentose sugar is deoxyribose
- base can be thymine
RNA :
- pentose sugar is ribose
- base can be uracil
describe how nucleotides join together to form polynucleotide
- condensation reactions , removing water molecules
- between Phosphate group of one nucleotide and deoxyribose / ribose of another
- forming phosphodiester bonds
why did many scientists initially doubt that DNA carried the genetic code
The relative simplicity of DNA - chemically simple molecule with a few components
describe the structure of DNA
- polymer of nucleotide
- each. nucleotide formed from deoxyribose , phosphate group and a nitrogen containing organic base
- phosphodiester bonds join adjacent nucleotides
- 2 polynucleotides chains held together by hydrogen bonds
- between specific complementary base pairs = adenine / thymine and cytosine / guanine
- double helix
deprive the structure of mRNA
- polymer of nucleotides
- each nucleotide formed from a ribose , phosphate group and a nitrogen containing organic base
- bases = uracil , adenine , cytosine and guanine
- phosphodiester bonds join adjacent nucleotides
- single helix
compare and contrast structure of DNA and mRNA
Dna :
penrose sugar is deoxyribose
- has the base thymine
- double stranded
- long
- has hydrogen bonds / base pairing
RNA :
- Pentose sugar is ribose
- has the base urscil
- single stranded
- shorter
- does not have hydrogen bonding
suggest how the structure of DNA relates to its functions
- two strands = both can act as a template for semi conservative replication
- hydrogen bonds between bases are weak = strands can be separated for replication
- complementary base pairing = accurate replication
- double helix with sugar phosphate backbone = protects hydrogen bonds
- long molecule = store lots of genetic information
- double helix = compact
suggest how you can use incomplete information about the frequency of bases on DNA strands to find the frequency of other bases
1) %’of adenine in strand 1 = % of thymine in strand 2
2) % of guanine in strand 1 = % of cytosine in strand 2
- because of specific complementary base pairing between 2 strands
