Mod 6 Ch. 24 Flashcards Preview

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Flashcards in Mod 6 Ch. 24 Deck (26):

Which of the following would NOT be consistent with the idea that a disorder has a genetic component?

The disorder can spread to individuals sharing similar environments


Assuming complete penetrance, which type of inheritance pattern is consistent with the pedigree shown here?

Autosomal recessive


Which of the following is NOT a common explanation for a dominant disorder?

A change in chromosome number


Locus heterogeneity refers to a genetic disorder that..

Is caused by mutations in two or more different genes


What is a haplotype?

The linkage of alleles or molecular markers along a chromosome


Haplotype association studies are aimed at the identification of a particular ___ based on ___.

Gene, its linkage to other genes or molecular markers


Which of the following is NOT a method used in genetic testing?

Chromosome walking


Which of the following prenatal genetic testing methods is done in conjugation with in vitro fertilization?

Preimplantation genetic diagnosis


A prion is a disease-causing agent composed of..

Protein alone


An oncogene is produced from a ___ that has acquired a ___.

Proto-oncogene, gain-of-function mutation


Which of the following is a type of genetic change that could produce an oncogene?

All of the above

Missense mutation
Gene amplification
Chromosomal translocation


Tumor-suppressor genes promote cancer when..

Their function is inactivated


Normal (nonmutant) tumor-suppressor genes often function..

- as negative regulators of cell division
- in the maintenance of genome integrity


Most forms of cancer involve..

The activation of multiple oncogenes and the inactivation of multiple tumor-suppressor genes


Personalized medicine may be used..

- to characterize types of tumors
- to predict the outcome of certain types of cancers
- to determine the proper dosage of drugs


A family pedigree of Tay-Sachs disease, indicating recessive inheritance.

What feature(s) of this pedigree indicate recessive inheritance?

The key feature is that affected offspring have both parents who are unaffected by the disease. The parents are heterozygous carriers.


A family pedigree of Huntington disease, indicating dominant inheritance.

What feature(s) of this pedigree indicate dominant inheritance?

That affected offspring have an affected parent


A family tree of hemophilia A in the royal families of Europe, indicating an X-linked recessive inheritance.

What feature(s) of this pedigree indicate X-linked recessive inheritance?

That all the affected individuals are males. Furthermore, these males all have mothers who were descendants of Queen Victoria


What is a haplotype?

Refers to the linkage of alleles or molecular markers along a chromosome


The transmission pattern of a molecular marker for Huntington disease.

Explain the connection between the founder and the G8-C marker.

In this example, the original mutation that caused the Huntington allele occurred in a germ-line cell or gamete of a founder such that the Huntington allele was linked to the G8-C marker.


A proposed molecular mechanism of prion diseases.

Where does the PrP^Sc protein come from?

May come from eating infected meat or some people have a genetic predisposition that occasionally caused the PrP^C protein to convert to the PrP^Sc protein.


Functional cycle of the Ras protein.

How would a mutation that prevents the Ras protein from hydrolyzing GTP affect the EFG pathway described?

Such a mutation would keep the Ras protein in an active state and thereby promote cancerous growth. The EGF pathway would be turned on.


The reciprocal translocation commonly found in people with chronic myelogenous leukemia.

Why does this translocation cause leukemia rather than cancer in a different tissue type, such as the lung?

The bcr gene is expressed in white blood cells. This translocation causes abl gene to be under the control of the bcr promoter. The abnormal expression of abl in white blood cells causes leukemia.


Interactions between the Rb and E2F proteins.

If a cell cannot make any Rb protein, how will this affect the function of E2F?

E2F will be active all of the time, and this will lead to cancer.


Cell-cycle control.

What is a checkpoint?

A point in the cell cycle in which proteins detect is the cell is in the proper condition to divide. If an abnormality such as DNA damage is detected, the checkpoint proteins will halt the cell cycle.


Inheritance pattern of familial breast cancer.

Explain why familial breast cancer shows a dominant pattern of inheritance in a pedigree even though it is recessive at the cellular level.

An individual with a predisposition for familial breast cancer inherits only one copy of the mutant allele. Therefore, it shows a dominant pattern of inheritance. However, to actually get breast cancer, the other allele must become mutant in somatic cells.