BIO Chap 15

What are ways that point mutations may alter a gene?

A nucleotide is added to a gene. The base sequence within the gene is changed. A nucleotide is removed from a gene.

The test used to evaluate the ability of a substance to cause mutations, and which employs a bacterium that cannot synthesize the amino acid histidine, is the ________ test

Ames Test

In most cases, how many genetic changes in a cell lineage typically occur before cancer develops?

At least 10

Xeroderma pigmentosum and Cockayne syndrome are genetic diseases that affect ______.

DNA repair

What are causes of spontaneous mutations?

Errors made by DNA polymerase during replication Free radicals produced during metabolic processes that change nucleotide structure Insertion of a transposon into a gene

Which of the following are causes of spontaneous mutations?

Errors made by DNA polymerase during replication Free radicals produced during metabolic processes that change nucleotide structure Insertion of a transposon into a gene

Which of the following are examples of ionizing radiation?

Gamma rays X-rays

What are the three most common ways that the function of a tumor-suppressor gene is lost?

Loss of the chromosome that carries the gene Abnormal DNA methylation near the gene's promoter Mutation within the gene

What type of mutation results from abnormalities that naturally occur during biological processes?

Spontaneous

Where must a mutation occur if it is to directly affect an amino acid sequence?

The coding region of a structural gene.

In nucleotide excision repair, what serves as the template for synthesis of new DNA to replace the damaged strand?

The complementary strand of DNA

What does a gene mutation affect?

The sequence of bases in a particular gene

What's true about nucleotide excision repair (NER)?

The undamaged strand is used as a template to synthesize a normal strand. A region of several nucleotides in the damaged strand is removed from the sequence.

What are the typical functions of proteins encoded by genes that may become oncogenes?

Transcription factor Growth factor receptor Intracellular signaling protein

Which of the following genetic diseases affect DNA repair systems in humans?

Xeroderma pigmentosum Cockayne syndrome

What have the ability to repair DNA and thus minimize mutations?

all living things

How do point mutations affect DNA sequences?

by adding or subtracting a single base pair by substituting one base for another

The disease of multicellular organisms that is characterized by uncontrolled cell division is known as ______

cancer

Some tumor-suppressor genes encode proteins that test the integrity of the genome and prevent a cell from progressing past a certain stage in the cell cycle. These proteins are termed _________ proteins

check point proteins

What are the two types of proteins that are responsible for advancing a cell through the phases of the cell cycle?

cyclins Cyclin-dependent kinases

The two proteins that advance a cell through the four phases of the cell cycle are called _________ and _________ - dependant ________

cyclins cyclin kinases

What is the purpose of the Ames test?

evaluation of the ability of a substance to cause mutation

Mutations that occur in noncoding sequences may affect gene ______

expression, transcription, or regulation

Relatively small changes in DNA sequence are known as ______

gene mutations

Cells that give rise to gametes, such as egg and sperm cells, are known as the _______ - _______ cells.

germ line cells

Gametes are produced by ______.

germ-line cells

X-rays and gamma rays are examples of _______ radiation, which is a type of electromagnetic radiation that can create free radicals.

ionizing radiation

Mutations in noncoding sequences ______.

may affect gene expression

When oncogenes are ______ compared to proto-oncogenes, they can promote certain types of cancer.

over active

Bacterial colonies can be transferred from a master plate to secondary plates in the same configuration using a transferring agent such as a sterile velvet cloth. This technique is known as _________ ________

replica plating

An overgrowth of cells, which can be benign or become cancerous, is known as a(n) ________

tumor

Genes that normally function to prevent cancerous growth are called ______.

tumor suppressor genes

Maintenance of genome integrity and negative regulation of cell division are the two main functions of ______.

tumor-suppressor genes

Cancer is characterized by ______.

uncontrolled cell division