4785584
Description
Flashcards by Charlotte Hewson, updated more than 1 year ago
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Created by Charlotte Hewson
about 8 years ago
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| Question | Answer |
| what is used to get the DNA code into the cytoplasm? | RNA |
| what does mRNA do? | transfers DNA code from nucleus into cytoplasm |
| why is mRNA used? | it is small enough to pass through nuclear pores and enter cytoplasm |
| what is the genetic code? | the sequence of bases on mRNA |
| why is the mRNA not identical to the DNA? | it is complementary to it |
| what is a codon? | the sequence of three bases on the mRNA that codes for a single amino acid. |
| what are the six main features of the genetic code? | - each amino acid is coded by 1 codon - a few a.a. only have one codon the code is degenerate (most a.a. have more than one codon) - three stop codons mark end of chain - non-overlapping - universal |
| what is each nucleotide in the RNA polymer made up of? | - the pentose sugar ribose - one of the organic bases (A, G, C or U) - a phosphate group |
| what are the two types of RNA? | messenger RNA and transfer RNA (mRNA and tRNA) |
| what is mRNA structure? | many mononucleotides in a long strand in a double helix. |
| what happens once the mRNA has left the nucleus? | it associates with ribosomes where it acts as a template for proteins to be built. |
| how is mRNA structure suited to its function | possesses correct sequences for specific polypeptides is easily broken down so only exists whilst needed to make protein. |
| describe the structure of tRNA | around 80 nucleotides, single stranded chain folded into a clover with one end extending beyond the other where amino acids can attach. opposite end has an anticodon, each a.a. has its own anticodon |
| what is the base replacement in RNA? | Thymine (T) to Uracil (U). |
| what can RNA link with? | DNA or other RNA |
| what happens at the anticodon during protein synthesis? | anticodon pairs with complementary organic bases that make up the codon on the mRNA. A.a. attach to extended chain. |
| how is tRNA adapted? | lines up amino acids on the mRNA |
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