Cellular Control

Question 1

what is a mutation

Answer 1

an alteration to the DNA base sequence

Question 2

what are addition or deletion mutations

Answer 2

where one or more nucleotide is added or deleted
frame shift means whole amino acid will be different

Question 3

what is a substitution mutation

Answer 3

when a nucleotide is replaced by another

Question 4

how is gene expression regulated at transcriptional level

Answer 4

transcription factors
proteins that can initiate or inhibit transcription of genes so only vertain part expressed

Question 5

describe the function of lac operon in low lactose concentrations

Answer 5

E.coli can use lactose as a respiratory substrate through enzymes
when lactose conc low the lac operon binds to gene that make this enzyme and inhibit its expression

Question 6

describe the function of lac operon in high lactose concentrations

Answer 6

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

Question 7

how is gene expression regulated post transcriptional level

Answer 7

splicing
primary mRNA contains both coding regions (exons) and non coding regions (introns)
introns removed to produce mature mRNA ready for translation

Question 8

how is development controlled by homeobox genes

Answer 8

code for transcription factors that activate genes when needed during development

Question 9

how is development controlled by mitosis

Answer 9

mitosis is primary mechanism of growth
genes regulating mitosis respond to stimuli to control rate of growth

Question 10

how is development controlled by apoptosis

Answer 10

programmes the death of cells
keeps cell division at a constant rate to prevent cancer