Concept explainers
C.1Identify the normal functions of the genes whose mutations are associated with development of cancer.
RBI(retinoblastoma)
c
p
APC(familial adenomatous polyposis)
Which of these genes would you classify as a protooncogene and which as a tumor suppressor gene? Explain your categorization for each gene.
To review:
To identify normal function of the given genes, as the mutation of these genes is related to cancer development.
The normal function of
The normal function of
The normal function of
The normal function of APC is to be identified.
The proto-oncogene and tumor suppressor genes is to be classified.
Introduction:
Proto oncogenes are those which perform normal function in the cell cycle. Mutation in proto oncogenes results in over expression of proto oncogenes which leads to uncontrolled cell division, now, they are termed as oncogenes. On the other hand, genes normally faction in DNA damage repair and control the normal cell cycle. If mutation occurs in this gene, they lose their function and DNA damage cannot be repaired; in such condition, the cell is termed as transformed, and it undergoes uncontrolled cell division.
These genes prevent cell transformation and maintain a normal cell cycle and are termed as tumor suppresser genes.
Explanation of Solution
RB1 normally inhibit the
APC (Adenomatous polyposis coli) functions as a tumor suppresser gene. It is involved in proteolytic cleavage and degradation of
Proto oncogenes accelerate rate of normal cell division and are responsible for the formation of tumors. Tumor suppresser genes suppress the formation of tumor.
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Chapter C Solutions
Genetic Analysis: An Integrated Approach (3rd Edition)
- Explain the molecular mechanisms of cancers caused by a P53 gene mutation.arrow_forwardThere are three broad categories of cancer-related genes: proto-oncogenes, tumor suppressor genes, and DNA stability/repair genes. Define each of these categories and indicate which one you think the RB1 gene belongs to and why.arrow_forwardillustrate some of the molecular mechanisms leading from loss-of-function mutations in tumor-suppressor genes to increased predispositions to cancer?arrow_forward
- Define tumor-suppressor genes. Why is a mutation in a single copy of a tumor-suppressor gene expected to behave as a recessive gene?arrow_forwardClassify the following genes as proto-oncogenes or tumor-suppressor genes: p53, ras, Bcl-2, telomerase, jun, andarrow_forwardDescribe how mutations in genome maintenance factors promote tumorigenesis. Why would inactivation of a mis- match repair gene cause colon cancer?arrow_forward
- How tumor-suppressor genes contribute to cancer whenmutated or abnormally expressed ?arrow_forwardHow can the role of epigenetics in cancer be reconciled with the idea that cancer is caused by the accumulation of genetic mutations in tumor-suppressor genes and proto-oncogenes?arrow_forward46. Explain why mutations in oncogenes are generally dominant while those in tumor suppressor genes are recessive.arrow_forward
- Explain about the TP53 Tumor-suppressor Gene ?arrow_forwardGenetic instability in the form of point mutations, chromosome rearrangements, andepigenetic changes needs to be maximal to allow the development of cancer.(a) With diagrams explain:(i) point mutations (ii) chromosome rearrangement (iii) epigenetic changesarrow_forward1. a)Proteins that stimulate/promote progression through the cell cycle are encoded by (oncogenes or tumor suppressor genes). Boldface one. b)Proteins that inhibit progression through the cell cycle are encoded by (oncogenes or tumor suppressor genes). Boldface one. c)What is the difference between a proto-oncogene and an oncogene? d)To cause cancer, proto-oncogenes require (1 or 2)allele(s) to be mutated and therefore are considered (dominant or recessive). The mutation results in a (loss or gain) of function. For each underlined pair, boldface one. e)To cause cancer, tumor suppressor genes require (1 or 2)allele(s) to be mutated and therefore are considered (dominant or recessive). The mutation results in a (loss or gain) of function. For each underlined pair, boldface one.arrow_forward
- Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax