biology cellular control

An alteration to the DNA base sequence, often arise spontaneously during DNA replication

- Where one or more nucleotides (bases) are either inserted or deleted from the DNA sequence. - More likely to be either harmful or beneficial, due to the frame shift which means the entire amino acid sequence will be different

Where a nucleotide in te DNA sequence is replaced by another - more likely to be a neutral mutation, meaning no change occurs in the amino acid sequence

Transcription factors are proteins that can either initiate or inhibit the transcription of genes s that only certain parts of the DNA are expressed

e coli can use lactose as a respiratory substrate via use of an enzyme when lactose conc is low the lac operon binds to the gene that makes this enzyme and inhibits its expression

lactose binds to the operon causing it to change shape and unattach from the gene allowing RNA polymerase to bind and the gene to be expressed

Splicing, primary mRNA contains both coding regions (exons) and non coding regions (introns) the introns are removed to produce mature mRNA ready for translation

Activation of proteins such as adrenaline binds to a receptor an enzyme is activated whuch converts ATP to cyclic AMP. Prompts further enzyme reactions which activates the protein

Code for transcription factors that activate genes when theyre needed during the development of a zygote their sequences are similar in plants, animals and fungi

Mitosis (cell replication) is the primary mechanism of growth, genes regulting mitosis respond to varous stimuli both internal and external in order to control rate of growth

programmes the death of cells, it is highly controlled and keeps cell division a a constant rate so as to prevent cancer.