ch.13 altering the genetic material: mutation, cancer
Which of the following 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 base pair is removed from a gene.
Which of the following are ways that chemical mutagens covalently modify the structure of nucleotides?
Alkylation of bases Deamination of bases
Which of the following are ways that ionizing radiation can alter DNA structure?
Base deletion Breaks in one or both DNA strands
What are the typical functions of proteins encoded by genes that may become oncogenes?
Growth factor receptor Transcription factor Intracellular signaling protein
What is the function of the Rb protein?
It inhibits cell division.
What is the function of the p53 protein?
It is a transcription factor.
What does a gene mutation affect?
The sequence of bases in a particular gene
A mutation is best defined as:
a heritable change in the genetic material
The effects of _________ mutagens on DNA structure is varied. Some can alkylate bases, others act as base analogues, and a few can insert between bases in the double helix and cause additions or deletions.
chemical
A mutation may affect the amino acid sequence of a polypeptide only if it occurs within the
coding sequence of a structural gene.
The protein product of what tumor-suppressor gene acts to sense DNA damage, promote DNA repair, and halt cell division?
p53
Biologists categorize the causes of mutation as _________ which result from errors in normal processes, or induced, which are caused by external agents.
spontaneous
What are the three most common ways that the function of a tumor-suppressor gene is lost?
Abnormal DNA methylation near the gene's promoter Loss of the chromosome that carries the gene Mutation within the gene
The _____ test, which was developed in the 1970s, is used to evaluate the ability of a substance to cause mutations.
Ames
Which of the following are ways that chemical mutagens covalently modify the structure of nucleotides?
Deamination of bases Alkylation of bases
True or false: Cancer usually requires only one or two genetic changes to the same cell lineage.
False cancer usually requires around 10 or more genetic changes to the same cell lineage.
Which of the following are ways that point mutations may alter a gene?
The base sequence within the gene is changed. A nucleotide is added to a gene. A base pair is removed from a gene.
The p53 protein can arrest the cell cycle at the G1 stage by:
activating genes that encode proteins that stop the cell cycle
A chemical that resembles a normal base and therefore can substitute for it during DNA replication is said to be a(n)
base analogue
A chemical that resembles a normal base and therefore can substitute for it during DNA replication is said to be a(n) Multiple choice question.
base analogue
Mutations that occur within a noncoding DNA sequence affect ______ _____________
gene expression
Cells that give rise to gametes, such as egg and sperm cells, are known as the _______ _______ cells
germ line
gametes are produced by
germ line cells
Over the past four decades, researchers have identified many types of ______. Examples include growth factor receptors, transcription factors, and intracellular signaling proteins.
oncogenes
A normal gene that can become an oncogene if it is mutated is called a(n)
proto-oncogene
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 planting
Nonionizing radiation, such as ultraviolet light, can lead to:
the formation of a thymine dimer
The protein p53 is encoded by a(n):
tumor-suppressor gene
Maintenance of genome integrity and negative regulation of cell division are the two main functions of:
tumor-suppressor genes
