Unit 2 Short Answer Question (Do NOT leave blank): Use the following words to fill in the blanks: transcription, dairy products, enzymes, proteins, repressor, rna polymerase, lactose intolerant, lactase, operator, ecoli, transcribe, bases, repressor, operator. An example of prokaryotic gene expression is the lac operon. When a person is 1), they do not produce the enzyme 2), which aids in the digestion of lactose, the sugar found in 3). If a person who is lactose intolerant eats or drinks a dairy product, lactose travels down the digestive tract into the large intestine, where the genes in the bacteria, 4) , are turned on to create the 5) / 6) needed to digest the lactose. In E. Coli, when lactose is present, it acts as an inducer and binds to the 7) protein, keeping it from attaching to the 8). 9) then is able to attach to and 10) the E. Coli gene by matching up the 11). When lactose is NOT present, the 12) protein binds to the 13 and transcription is blocked. This is an example of gene expression (production of proteins) being controlled at 14).

1. lactose intolerant

2. lactase

3. dairy products

4. E.coli

5. enzymes

6. proteins

7. repressor

8. operator

9. RNA polymerase

10. transcribe

11. bases

12. repressor

13. operator

14. transcription

Explanation:

Lac operon is good example of prokaryotic gene regulation. The lactose operon or lac operon is a type of operon which is use to transport  and metabolize the lactose in E.coli and other bacteria. The lac operon is made up of three important components including promoter, an operator, and three genes that encode the enzymes required for lactose digestion.

A person who is lactose intolerant is unable to produce the enzyme lactase, which helps in the digestion of sugar generally present in dairy products. The lac operon is regulated by lactose in the environment.

So, when lactose intolerant people consume dairy products, the gens in bacteria E.coli present in the large intestine, turn on to produce enzyme or  proteins required to digest the lactose.

When lactose is present, lac operon in E.coli, acts as an inducer and binds to the repressor protein which prevent it binding to the operator. RNA polymerase the binds to the promoter and transcribe the E.Coli gene by matching the base pair or bases.

When lactose is absent, repressor protein is allow to bind to the operator and inhibit the transcription process in E.Coli. The whole process is regulated during transcription in prokaryotes that involves lac operon.

Hence, the correct words for the blanks are as following:

1. lactose intolerant

2. lactase

3. dairy products

4. E.coli

5. enzymes

6. proteins

7. repressor

8. operator

9. RNA polymerase

10. transcribe

11. bases

12. repressor

13. operator

14. transcription

b c a d mark me

oceans

indian ocean

pacific ocean

atlantic ocean

arctic ocean

southern ocean