Gene Expression

Mind Map by georgia_rae, updated more than 1 year ago
Created by georgia_rae almost 5 years ago


mutations, protein synthesis, metabolic pathway

Resource summary

Gene Expression
1 Proteins
1.1 Fibrous
1.1.1 Structure
1.2 Globular
1.2.1 E.g. Enzymes or hormones
1.3 Coded by genes
1.3.1 Gene is a section of DNA
2 Transcription
2.1 FIrst stage of protein synthesis
2.2 Occurs in the nucleus
2.3 DNA unwinds + unzips
2.3.1 Coding strand identical to mRNA strand, except T instead of U
2.3.2 Template strand 3 bases called triplet code for mRNA strand 3 bases called codon processed introns are removed exons are joined to together mRNA leaves the nuclues translation begins using complementary base pairing rule instead U replaces T
2.4 PURPOSE: mRNA transcribes the code for a polypeptide chain from the DNA. so the original DNA does not get damaged
3 Translation
3.1 mRNA enters cytoplasm and moves to the ribosome
3.1.1 the ribosome moves along the mRNA reading the code the tRNA pairs with the mRNA using complementary base pairing rule the mRNA acts as a code for the tRNA the tRNA as an amino acid joined the coded for amino acids join together by peptide bonds forming a polypeptide chain A stop codon is read the polypeptide chain is released into the cytoplasm folds up in a particular way to produce a fuctional protein the protein is used fro cellular functions 3 bases on tRNA is called anti-codon
3.2 PURPOSE: to use the mRNA to make a polypeptide chain/protein. so the protein can be used for cellular functions
4 Mutations
4.1 A change in the DNA base sequence
4.2 can be harmful or helpful
4.3 Somatic mutation
4.3.1 mutation in body cells, cannot be inherited
4.4 Gametic Mutation
4.4.1 mutation in gametes, can be inherited by offspring
4.5 Mutagen
4.5.1 causes mutations e.g. UV light, chemicals
4.6 Deletion
4.6.1 A base is deleted Frameshift Making the reading of the triplets change along one. the following triplets affected, resulting in different amino acids different coded for protein or unfunctional protein
4.7 Insertion
4.7.1 A base is inserted
4.8 Substitution
4.8.1 one base swapped for another
4.8.2 Missense changes the amino acid
4.8.3 Nonsense changes the amino acid to a stop
4.8.4 silent does not change the amino acid no affect on protein due to redundancy due to degeneracy more than one codon codes for the same amino acid e.g. UUU and UUC, both code for Phe
5 Metabolic Pathway
5.1 Linked biochemical reactions controlled by enzymes that maintain life processes in organisms
5.2 the reactants of one reaction are the products for the previous reaction
5.3 mutation occur may result in a enzyme not being produced or too much
5.3.1 causing a build up of one product phenotype may be affected
6 Environmental Influences
6.1 genotype + environment ------> phenotype
6.2 temperature
6.3 light
6.4 moisture
6.5 minerals
6.6 nutrients
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