Zusammenfassung der Ressource
DNA - Genetic Code
- Genetic Code
- Characteristics
- It is a triplet code - 4 to the power
of 3 = 64 - only twenty amino acids
used for protein synthesis
- It is a degenerate code (all amino
acids have more the one code) apart
from methionine.
- stop and start codons
- wide spread but not universal
- Transcription
- 1) The gene to be transcribed, unwinds and unzips by dipping into
the nucleus, hydrogen bonds between base pairs break
- 2) activated RNA nucleotides hydrogen bonds to the
exposed complementary base pairs - catalysed by RNA
polymerase
- 3) The two extra phosphates are released,
providing energy for bonding of adjacent molecules
- 4) The mRNA produced is complementary to the template strand
and is therefore a copy of the coding strand of DNA.
- 5) The mRNA is released from the DNA and
passed out of the nuclear pore to a ribosome
- Is the creating of a single-stranded mRNA copy of the DNA coding strand
- Genome
- The genome of an organism is the entire DNA sequence of that organism,
the human genome consists of about 3 billion nucleotide base pairs