19) The initiation complex for protein synthesis contains all of the following e

Question

19) The initiation complex for protein synthesis contains all of the following except a) a small ribosomal subunit. b) mRNA c) tRNA with methionin d) a release factor. e) an initiation factor. 20) The diferent components of the protein synthesizing machinery include all of the following except a) mRNA b) tRNA c) ribosomes. d) amino acids. e) RNA polymeras 21) Eukaryotic mRNA molecules are occasionally interspersed with non-coding sequences that must be removed before protein synthesis. These are called a) anticodons. b) introns c) exons. d) nucleosomes. e) chromomeres 22)Humans and a bacterium make human insulin. How is this possible? a) The human insulin gene appears naturally in the bacteria b) The human insulin gene is a mutated form of a bacterial gene for bacterial insulin. c) The human insulin gene was inserted into a bacterium's genome, and since the genetic code is nearly universal, the bacterium is able to produce human insulin. d) The human insulin gene appears in bacteria that have been exposed to radiation treatments for diabetes. e) The human insulin gene appears naturally in the bacteria that is an inhabitant of the GI tract of diabetic patients. 23)There are 45 different kinds tRNA (anticodons) available to serve as amino acid carriers, but there are 64 mRNA codons. Why aren't the tRNA anticodons and mRNA codons equal in number? a) The reason is that the third base pair on the tRNA allows some flexibility (wobble); thus, b) The reason is that some tRNA anticodons can misread some of the mRNA codons, which c) The reason is that the third base pair on the mRNA codon allows some flexibility (wobble); d) The reason is that the tRNA has the flexibility to choose which mRNA codons are necessary some tRNA anticodons can recognize more than one mRNA codon. creates a "wobble in the tRNA anticodons that can be repaired by RNA repair enzymes. thus, some tRNA anticodons can recognize more than one mRNA codon. for building the polypeptide chain.

Explanation / Answer

19. The initiation complex for protein synthesis consists of two ribosomal subunits and fmet tRNA which assemble on a properly aligned mRNA to form a complex. This assembly process also requires the participation of protein initiation factors that are not permanently associated with ribosome. Initiation involves three initiation factors as IF-1, IF-2, IF-3. Hence, release factor is not a part of initiation complex. So, d. is the correct option.

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