structure of DNA and RNA Flashcards
3.1.5.1
what does DNA stand for?
deoxyribonucleic acid
whats the function of DNA?
to carry genetic material
what does DNA need to be able to do?
- encode information
- be a stable structure
- be copied accurately
describe the structure of DNA
DNA is composed of lots of DNA nucleotides joined together by phosphodiester bonds (condensation reactions) to form a polynucleotide
what is DNA comprised of?
a phosphate group, a deoxyribose sugar and a nitrogenous base
what are the four different nitrogenous bases?
Adenine
Thymine
Guanine
Cytosine
what are the complementary nucleotide bases?
Adenine + Thymine
Guanine + Cytosine
describe DNA strands
in DNA many nucleotides join together to form a polynucleotide. the base pairings A-T and G-C are described as complementary to each other. DNA is made up of two strands of polynucleotides, they run antiparallel to each other. each strand is held together by hydrogen bonds between the bases, 3 between G-C and 2 between A-T
describe the structures of DNA that allow it to be copied accurately
- complementary bases held by weak hydrogen bonds, so they can be broken easily to separate the strands during DNA replication
- DNA is double stranded, so both strands can act as a template during DNA replication
- complementary base pairs, so strands can be faithfully copied + produce identical DNA molecules in DNA replication
describe the structures of DNA that allow it to encode information
- a long molecule, so it can store lots of genetic information
- ** a helix and tightly coiled**, so its compact
- the base sequence, codes for amino acids
describe the structures of DNA that allow stability
- many hydrogen bonds, so it is a stable structure
- bases in the middle of the double helix, so they are protected by the sugar phosphate backbone
what is RNA compromised of?
lots of nucleotides (RNA) joined together by phosphodiester bonds formed in condensation reactions to form a polynucleotide
whats the differences between DNA and RNA?
- RNA is single stranded whereas DNA is double stranded
- RNA has ribose sugar whereas DNA has deoxyribose sugar
- RNA has uracil instead of thymine
what are the three types of RNA?
- mRNA
- tRNA
- rRNA