4.2 DNA and protein synthesis Flashcards
Define genome
complete set of genetic information in the cells of an organism
Define proteome
complete set of proteins that can be produced by a cell
Describe the structure of messenger RNA
A long, single strand.
Its base sequence is complementary to the DNA it was transcribed from.
suggest advantages of using mRNA rather than DNA for translation
. shorter & contains uracil = breaks down quickly so no excess polypeptide forms
. single-stranded & stranded = ribosome moves along strand & tRNA binds to exposed bases
. contains no introns
Describe the structure of transfer RNA
A single strand of around 80 nucleotides that is folded in a clover leaf shape.
On one end is an anti-codon, on the opposite end is the amino acid binding site
What is produced by transcription?
mRNA
Where does transcription take place?
In the nucleus
Outline the process of transcription
. DNA uncoils into two strands with exposed bases. One used as a template
. Free nucleotides line up next to their complementary bases, and are joined together by RNA polymerase.
What happens to mRNA after transcription?
In eukaryotic cells, pre-mRNA must be spliced to remove introns, leaving only the coding regions. Then it moves out of the nucleus and attaches to a ribosome.
What is produced by translation?
Proteins
Where does translation take place?
in the cytoplasm
Outline the process of translation
. The anti-codon of tRNA attaches to complementary bases of the mRNA
. Amino acids bonds to tRNA form peptide bonds, continuing to form a peptide chain until a stop codon is reached
. Process requires ATP
