chapter 12 Flashcards
what is transcription?
just scription is a process when the messenger RNA a.k.a. M RNA is made from a gene within the DNA. M RNA is A single-stranded he likes whereas DNA is double-stranded helix.
what is translation?
translation is a process of using the mRNA to direct the production of a protein.
RNA polymerase and function
A protein called RNA polymerize produces the mRNA copy of DNA during transcription. It first binds to one strand of the DNA at a site called the promoter and then moves down the DNA molecule and assembles a complementary copy of RNA. RNA uses Uracil (U) instead of thymine (T). The complementary strand ends at the terminator site which is shaped like a hairpin loop.
what are codons?
to correctly read a gene, a cell must translate the information encoded in the DNA to get a nucleotides into the language of proteins a.k.a. amino acids. Translation follows rules set out by the genetic code. The mRNA is red and three nucleotides called codons. Each codon corresponds to a particular amino acid.
structure of the ribosome?
A ribosome is composed of two subunits: a large subunit and a small subunit. Between the large ribosomal subunits and the small ribosomal subunits, there is on the e site, P site, and a site. There is also the M RNA binding site.
The structure of tRNA is important to its function
it has an amino acid attachment site at one end and a three nucleotide sequence at the other end. This three nucleotide sequence is called the anti-codon and is complementary to one of the 64 codons of the genetic code. Activating enzymes match amino acids with the proper tRNAs. The tRNA looks like a cloverleaf.
start codon
A UG – methionine
located at the peptide site
stop codon
UAA, UAG, UGA
Central dogma
The path that DNA takes
DNA –> RNA –> protein
The use of information in DNA to direct the production of particular proteins is called gene expression, which takes place in two stages
