BRAINCAKETranscription
Protein synthesis consists of two stages.
In the nucleus the DNA of a single gene is copied as a complementary mRNA strand. This leaves the nucleus through nuclear pores and associates with ribosomes in the cytoplasm.
tRNA molecules attached to amino acids bind temporarily to the mRNA in the order determined by the base sequence on the mRNA.
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Key terms in this lesson
- hydrogen bond
- A weak electrostatic attraction between a slightly positive hydrogen atom on one polar molecule and a slightly negative atom, such as oxygen or nitrogen, on another.
- nucleotide
- A molecule made of a pentose sugar, a phosphate group and a nitrogen-containing base.
- DNA polymerase
- The enzyme that joins free nucleotides together to form a new complementary strand of DNA.
- ribosome
- A small organelle, made of RNA and protein, that is the site of protein synthesis.
- gene
- A length of DNA that codes for a polypeptide or a functional RNA molecule, at a specific locus on a chromosome.
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