Chapter 12, Problem 19P

Summary Introduction

(a)

To explain:  

The following statement “colon cancer cells often contain mutations in gene encoding prostaglandin E₂ receptor. PGE₂ is a growth factor which is required for division of cells in gastrointestinal tract”.

Introduction:

Mutation in an organism is defined as a permanent alteration of “nucleotide sequences”. The mutations can be harmful, beneficial or neutral depending on the location of alteration in the genome and the effect exerted by the environment.

(b)

Summary Introduction

To explain:

The following statement “ Kaposi sarcoma is a common tumor in people with untreated AIDS which is caused by virus carrying gene for a protein similar to Chemokines receptors CXCR1 and CXCR2. Chemokines are cell-specific growth factors.

Introduction:

Kaposi’s sarcoma is defined as a type of cancer which leads to forms masses of skin, lymph nodes or into other organs. The skin lesions appear in purple color. It forms patches of abnormal tissues under skin, lining of mouth and throat, in lymph nodes.

(c)

Summary Introduction

To explain:

The following statement “adenovirus is a tumor virus that carries gene for protein E1A which binds to retinoblastoma protein, pRb.

Introduction:

Adenoviruses are defined as medium-sized and non-enveloped virus. They are composed of icosahedral nucleocapsid that contains double stranded DNA genome. They can cause infections in lining of eyes, airways and lungs, intestine, urinary tract and so on.

(d)

Summary Introduction

To explain:

The following statement “an important feature of many oncogenes and tumor suppressor genes is their cell-type specificity”.

Introduction:

Oncogenes are a type of gene that are capable of causing cancer. In tumor cells, such genes are mutated and expressed at high levels. They are sequence of DNA which is altered or mutated from its original form.