Red- Steven

7.4.1
Every single amino acid has a tRNA activating enzyme that will allow the tRNA to bind with an mRNA. There is a three part activating site for the tRNA and they consist of the ATP, the amino acid, and the tRNA activating enzyme. The process consists of the activating enzyme attaching the amino acid to the tRNA and this is a process that uses ATP as its energy source.
7.4.2
A ribosome consists of two separate subunits which are the small and large subunits. A large subunit is made up of three different rRNA and a number of protein molecules. A ribosome will most likely have a mRNA binding site along with two tRNA binding sites.
7.4.3
Translation consists of four different stages initiation, elongation, translocation, and termination.
7.4.4
Translation occurs in a 5 to 3 direction because the start codon is nearer to the 5 end than





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7.4.5 -
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7.4.6 - As a molecule of mRNA is moved through a ribosome, codons are translated into the amino acis, one by one, the process started by iniation through start codons. The interpreters are tRNA molecules, each type with a specific anitcondon at one end and a corresponding amino acid at the other end. A tRNA adds its amino acid cargo to a growing polypeptide chain when the anticodon bonds to a complementary codon on the mRNA (elongation) until termination occurs, ending elongation with a stop codon. Polysomes enable this process to occur very quickly by attaching a second ribosome on a strand of mRNA after the frst ribosome moves past he start codon; thus, a number of robosomes may trail along one mRNA.

7.4.7 - Free ribosomes are suspended in the cytoplasm and mostly synthesize proteins the dissolve into the cytoplasm and function there. Bound ribosomes are attached to the cytoplasmic end of the ER or the nuclear envelope. Bound ribosomes make proteins of the endomembrane system (the nuclear envelope, ER, Golgi apparatus, lyosomes, vacuoles, and plasma membrane) as well as proteins secreted from the cell (insulin). The ribosomes themselves are identical and can swith their status from being free to bound.

7.5.1 - Eukaryotic genes can contain exons and introns. An exon is a coding region of a eukaryotic gene. Exons, which are expressed, are seperated by introns. An intron is a noncoding, intervening squence ("useless") within a eukaryotic gene.