Structure of DNA and RNA (3.1.5.1) Flashcards
Part of Nucleic Acids Are Important Information-Carrying Molecules (3.1.5)
1
Q
Give examples of nucleic acids
A
- Deoxyribonucleic acid
- Ribonucleic acid
2
Q
What is the function of DNA?
A
- To hold genetic information
3
Q
What is the function of RNA?
A
- To transfer genetic information from DNA to the ribosomes
4
Q
What are phosphodiester bonds?
A
- Strong covalent bonds which consist of one phosphate group and two ester bonds
- Formed in a condensation reaction between phosphate and deoxyribose and catalysed by DNA polymerase
5
Q
What is each nucleotide made up of?
A
- Pentose sugar
- A nitrogenous base
- A phosphate group
6
Q
What is each DNA nucleotide made up of?
A
- Deoxyribose
- One of four nitrogenous bases: adenine, thymine, guanine or cytosine
- A phosphate group
7
Q
What is each RNA nucleotide made up of?
A
- Ribose
- One of four nitrogenous bases: adenine, uracil, guanine or cytosine
- A phosphate group
8
Q
What are polynucleotides?
A
- The polymers of nucleotides
9
Q
How are DNA polymers formed?
A
- Nucleotides within each strand join together through condensation reactions forming phosphodiester bonds between the deoxyribose sugar of one nucleotide and the phosphate group
- This creates polynucleotide chains with a sugar-phosphate backbone
10
Q
What is the structure of DNA?
A
- Polymer of nucleotides
- Each nucleotide formed from deoxyribose, a nitrogenous base and a phosphate group
- Nucleotides are joined by phosphodiester bonds to form a sugar-phosphate backbone
- DNA is double stranded and forms a double helix
- The two strands are held together by hydrogen bonds between complementary base pairs
- Adenine pairs with thymine and cytosine pairs with guanine
11
Q
How is the structure of DNA adapted for its function?
A
- The sugar-phosphate backbone → gives strength
- Being double stranded → so replication can occur using one strand as a template
- Being a large molecule → means that a large amount of information can be stored
- Many hydrogen bonds → gives stability to the molecule, individual hydrogen bonds being weak it allows the helix to unzip easily for replication
- Sequence of bases → codes for a specific sequence of amino acids in a polypeptide
- Complementary base pairing → enables information to be replicated accurately
12
Q
What is RNA?
A
- A relatively short polynucleotide chain and it is single stranded
