Saturday, March 6, 2010

From Gene to Protein_Chapter 17


1. What are the stages of transcription?
2. What is RNA splicing?
3. What are point mutations?

1. Initiation, elongation, and termination are the three stages of transcription.
2. Rna splicing takes places in eukaryotic cells. In rna splicing, large populations of the newly synthesized rna strand are removed. The sections of the mrna that are spliced out are introns, and the sections that remain and spliced together by a splicesome are called exons.
3. Point mutations are alterations of just one base pair of a gene. They come in two basic types. Base pair substituition, and insertation and deletion.

link on rna splicing :

point mutation:

5 main facts:
. The basic mechanics of transcription and translation are similar in eukaryotes and prokaryotes.
. The initial RNA transcript of any gene is called a primary transcript.
. Several codons may specify the same amino acid, but no codon specifies more than one amino acid.
. Some introns play a regulatory role in the cell. These introns contain sequences that control gene activity in some way.
. A point mutation that results in the replacement of a pair of complementary nucleotides with another nucleotide pair is called a base-pair substitution.

In this chapter we learnt that the information content of DNA is in the form of specific sequences of nucleotides along the DNA strands. The DNA inherited by an organism leads to specific traits by dictating the synthesis of proteins. Gene expression, the process by which DNA directs protein synthesis, includes two stages called transcription and translation. Proteins are the links between genotype and phenotype.

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