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2.7 91159 Gene Expression

Level 2

Four credits

External

This achievement standard involves demonstrating understanding of gene expression.

1 //Gene expression// involves a selection from the following biological ideas and processes:
 * nucleic acid structure and nature of the genetic code
 * significance of proteins
 * protein synthesis
 * the determination of phenotype via metabolic pathways
 * effect of environment on genotype through mutations
 * effect of environment on expression of phenotype.

2 Biological ideas and processes relating to nucleic acid structure and nature of the genetic code are selected from:
 * molecular components and their role in carrying the genetic code: nucleotide monomers, deoxyribose and/or ribose sugar, phosphate, nitrogenous bases, complementary base pairing resulting in coding and template strand
 * nature of the genetic code including triplets, codons and anticodons
 * redundancy due to degeneracy within the code.

3 Biological ideas and processes relating to the significance of proteins are selected from:
 * proteins as the products of gene expression: DNA à mRNA à polypeptide or protein
 * identification of one gene à one polypeptide relationship
 * significance of proteins is limited to their structural and catalytic role in living things.

4 Biological ideas and processes relating to protein synthesis are selected from:
 * the role of DNA sequence in determining the structure of a protein and how that protein is produced (transcription and translation)
 * the role of enzymes in controlling the process (specific names of enzymes are not required).

5 Biological ideas and processes relating to the determination of phenotype via metabolic pathways are selected from:
 * biochemical reactions are catalysed by specific enzymes and every enzyme is coded for by a specific gene(s)
 * biochemical reactions do not occur in isolation but form part of a chain reaction so that the product of one becomes the substrate of another step in metabolism
 * phenotype is determined by the presence, absence, or amount of specific metabolic products.

6 Biological ideas and processes relating to the effect of the environment on genotype through mutations are selected from:
 * mutagens (specific mutagens are recognised but their effect at molecular level is not required)
 * the potential effect on genotype and phenotype of gene mutations at the gene level.

7 Biological ideas and processes relating to the effect of environment on expression of phenotype involve ways that environmental factors may change phenotype without changing genotype.