mastering bio chp 11 and 12

A gene that causes a cell to become cancerous is called a(n)

oncogene

In a PCR reaction, the strands of DNA are first separated by ___.

heating

A(n) is a protein that promotes cell division. In excess, such a protein may lead to cancer.

growth factor

Operons are a standard method for gene regulation in _____.

prokaryotes but not eukaryotes

A normal gene that, if mutated, can lead to cancer is called a(n) .

proto-oncogene

What is the correct sequence of events that occur in a PCR reaction?

separation of DNA strands; addition of primers; use of DNA polymerase to produce second strand of DNA

DNA polymerase is a heat-sensitive enzyme. What is one thing that would need to be considered concerning the activity of this enzyme in PCR when the temperature is heated during each cycle to separate the DNA strands?

that the DNA polymerase could be denatured

To begin the process of gene transcription, RNA polymerase attaches to _____.

the promoter associated with the target gene

A(n) is a gene that encodes proteins that inhibit cell division. Such proteins normally help prevent cells from becoming cancerous.

tumor-suppressor gene

In gel electrophoresis DNA molecules migrate from _____ to _____ ends of the gel.

negative ... positive

Your body is composed of a dazzling array of different cell types. Each cell type develops its own unique properties. How does this happen?

All cells (with very few exceptions) contain the same set of genes, but the process of gene expression determines which genes are active in each cell.

The lac operon controls expression of three genes that produce lactose-digesting enzymes. What role does lactose play in regulating the lac operon?

It binds to and disables the repressor protein, thereby allowing production of the three enzymes.

When is PCR particularly applicable?

When there are small quantities of DNA to analyze

Within an operon, repressors _____.

block gene transcription to RNA by attaching to the operator