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MBH - Nucleic Acids
OCR A level Biology F212
Question | Answer |
---|---|
What is the function of DNA? How does its structure relate to this function? | Contains genetic information. Long and tightly coiled, so that a lot of information can fit into a small space in the cell nucleus. |
How do DNA molecules make self-replication easier? | Have a paired structure. |
What is a gene? | A section of DNA that codes for a specific sequence of amino acids that forms a particular protein. |
What is RNA used for? | To make proteins from the instructions contained within DNA. |
What is DNA? | A polynucleotide, made up from lots of joined nucleotides. |
What is a nucleotide made from? | A deoxyribose sugar, a phosphate group, and a nitrogen containing base. |
What is the same between nucleotides and what varies? | The same sugar and phosphate, varying nitrogen containing base. |
What are the pyramidines? | Cytosine, thymine and uracil. |
What are the purines? | Adenine and guanine. |
Which base pairs with adenine in DNA? | Thymine. |
Which base pairs with guanine in DNA? | Cytosine. |
What is the structure of DNA? | Two polynucleotides joined by hydrogen bonds between the bases, to form an anti-parallel double helix. Nucleotides join up between phosphate group and sugar. |
How many hydrogen bonds form between A and T? | Two. |
How many hydrogen bonds form between C and G? | Three. |
How does the sugar in RNA differ from that in DNA? | Ribose rather than deoxyribose. |
What is the difference in structure between RNA and DNA? | RNA is a single polynucleotide strand, DNA is a double one. |
What replaces thymine in RNA? | Uracil, pairs with adenine in RNA. |
What are different proteins made from? | A different number of amino acids in a different order. |
How is the order of amino acids in a particular protein determined? | By the order of nucleotide bases in a gene. |
How many bases codes for each amino acid? | Three. |
What do different base sequences code for? | Different amino acids. |
What are proteins used for? | All the reactions and processes of living organisms. |
Where are ribosomes found? | In the cytoplasm. |
What are DNA molecules too large to do? | Move out of the nucleus. |
What is DNA copied into? | RNA. |
What does RNA do? | Leaves nucleus and joins with ribosome in cytoplasm, where it can be used to synthesise a protein. |