lesson 7 regulation of gene expression

Question 1

what is gene regulation

Answer 1

gene regulation determines whether a gene is active or not
determiens the level of activity and the amount of protein available in teh cell

Question 2

what are constitutive genes

Answer 2

housekeeping genes that are always active because the proteins are neede dfor survival of the cell.
genes that code for dna repair and cell cycle regulation

Question 3

what are the three levels of control in prokaryotes

Answer 3

can occur during:
transcription
translation
and after a protein ahs been synthesized

Question 4

what is the operon

Answer 4

operon is the most common regulation during initiation of transcription
- in prokaryotes, genes are clustered in a region under the control of a single promotor. this is called an operon which is a cluster of genes goruped together under the control of one promotor
- one mRNA called a polycisronic mRNA is synthesized for multipe genes in the same metabolic pathway

Question 5

what is the lac operon

Answer 5

the genes that encode the enzymes needed to break dow nthe sugar lactose are found in the lac operon on the e.coli chromosome.
- the lac operon contains the coding region containing genes for three enymes tha t break down lactose and the regulator region

Question 6

what is the regulatory region components

Answer 6

the promotor which involves the transcription of the alctose metabolizing enzymes
the operator which is a dna sequence to which a protein/ a repressor binds to inhibit transcription initation
and the cap binding site which is a dna seuence to which cap binds to increase the rate of transcription