Ch 14 BIO 1200
what is the chance that a mutation in a parent's germ line cells will be passed on to his or her offspring? -75% -50% -0% -100%
50%
the expression of the p53 gene is included in response to: -proto-oncogenes -activation of capases -apoptosis -DNA damage
DNA damage
what is an example of how mutation in an operator site alters regulation of gene transcription? -a change in amino acid sequence so that the structure and function of the hemoglobin protein are altered -a change in nucleotide sequence, but no change in protein structure or function -a change of a DNA sequence in E. coli so that the lac repressor protein no longer binds to it
a change of a DNA sequence in E. coli so that the lac repressor protein no longer binds to it
What is a point mutation? -a mutation that occurs in a somatic cell -a mutation that is induced by an environmental agent -a mutation that changes a normal codon to a stop codon -a mutation that occurs at a particular developmental stage -a mutation that affects only a single base pair
a mutation that affects only a single base pair
What is a proto-oncogene? -a gene that encodes a protein that inhibits cell division -a normal gene that can become an oncogene if it is mutated -a gene that encodes a protein that is required for apoptosis -a gene that promotes cancer
a normal gene that can become an oncogene if it is mutated
a missense mutation may not affect protein structure and function if the altered amino acid has: -changed to a stop codon -a similar side chain -a different side chain
a similar side chain
a point mutation in which one base pair is replaced by another is known as a(n) ___________ substitution
base
a ________ tumor is precancerous and has not spread throughout the body
benign
arrange the stages of cancer progression in the correct order. start with the earliest form at the top. -malignant growth -benign growth -metastasis
benign growth malignant growth metastasis
how do point mutations affect DNA sequences? choose all that apply -by substituting one base for another -by rearrangement of nucleotides -by inserting a sequence of multiple base pairs into the existing DNA molecule -by reinserting a portion of the sequence in reverse order -by adding or subtracting a single base pair
by adding or subtracting a single base pair by substituting one base for another
the Rous sarcoma virus is an example of a virus that causes: -cancer -formation of thymine dimers -chromosome deletions -chromosomal translocations
cancer
agents that increase the likelihood of developing cancer are known as
carcinogens
what proteins monitor the integrity of the genome and prevent a cell from progressing through a certain point in the cell cycle? -capases -proto-oncogenes -checkpoint proteins -cyclins
checkpoint proteins
what are two types of proteins that are responsible for advancing a cell through the phases of the cell cycle? -cyclin-dependent kinases -tumor-suppressor genes -cyclins -DNA repair enzymes -capases
cyclins cyclin-dependent kinases
in what types of cells do germ line mutations occur? -skin -egg -sperm -skeletal muscle -brain -gamete-producing precursors
egg sperm gamete-producing precursors
mutations that occur in noncoding sequences may affect gene __________
expression
T/F: an oncogene is a mutated version of a normal gene. the oncogene is less active than the normal gene
false; it is a mutated version of a proto-oncogene
what type of mutation is the result of the insertion or removal of nucleotides that does not occur in multiples of three? -silent -nonsense -missense -frameshift
frameshift
cells that give rise to gametes, such as egg and sperm cells, are know as the _________ ____________ cells.
germ-line
animal cells are classified into two main types -non-stem cells -germ-line cells -stem cells -embryonic cells -somatic cells -adult cells
germ-line cells somatic cells
which of the following are examples of proteins encoded by oncogenes? -genome integrity proteins -transcription factors -DNA repair enzymes -intracellular signaling proteins -growth factor receptors
growth factor receptors intracellular signaling proteins transcription factors
what is the function of the p53 protein? -it is a cyclin-dependent kinase -it is a transcription factor -it is a capase -it is a DNA repair enzyme
it is a transcription factor
which of the following best describes the retinoblastoma (Rb) gene? -it is a proto-oncogene that encodes a growth factor receptor -it is a tumor-suppressor gene involved in the negative regulation of cell division -it is a proto-oncogene that encodes a transcription factor -it is a tumor-suppressor gene involved in the maintenance of genome integrity
it is a tumor-suppressor gene involved in the negative regulation of cell division
a specific type of point mutation called a(n) ____________ mutation is a base substitution that changes a single amino acid in a polypeptide sequence
missense
the two main functions of tumor suppressor genes are: -negative regulation of cell division -negative regulation of apoptosis -maintenance of genome integrity -positive regulation of cell division
negative regulation of cell division maintenance of genome integrity
a mutant gene that results in uncontrolled cell growth is known as a(n)
oncogene
consider a normal gene that is needed for growth. if this gene becomes overactive, it may contribute to cancer. it then becomes a(n) -homeobox gene -p53 gene -tumor-supressor gene -oncogene
oncogene
apoptosis is a term that refers to: -programmed cell death -mutations caused by radiation -formation of blood vessels -uncontrolled cell division -cancers of the stomach
programmed cell death
how does a frameshift mutation affect protein function? -it will likely inhibit protein function because the codon for an amino acid is changed to a stop codon, which will result in a truncated polypeptide -it may have either a neutral or negative effect on protein function depending on the amino acid that is now encoded -protein function is not affected because the mutation does not change the amino acid that is encoded -protein function is most likely inhibited because an entirely new amino acid sequence occurs downstream of the mutation
protein function is most likely inhibited because an entirely new amino acid sequence occurs downstream of the mutation
the original sequence of a DNA molecule is 5'-AACCGGTT-3'. match each mutates sequence with the correct description of the change that occured 5'-AACGGTT-3' -base substitution -single base addition -single base deletion
single base deletion
sperm and egg cells are termed germ line cells. in contrast, cells of the skin, muscle, heart, and liver are examples of?
somatic
all cells of the body that are not part of the germ line are called
somatic cells
silent mutations have no effect on the amino acid sequence of a polypeptide because: -mRNA does not recognize the base substitution, so the same polypeptide is produced during translation -although a base substitution occurs, the nucleotide excision repair system restores it to the original -the mutation changes only a single amino acid in the polypeptide sequence -the base substitution results in a codon that specifies the same amino acid as the original sequence
the base substitution results in a codon that specifies the same amino acid as the original sequence
where must a mutation occur if it is to directly affect an amino acid sequence? -transcriptional regulatory elements -the promoter of a gene -the coding region of a structural gene -an operator site -the intergenic region
the coding region of a structural gene
How do nonsense mutations affect protein function? -translation is terminated where the mutation occurs, producing a truncated polypeptide which is unlikely to function correctly -because multiple codons can specify the same amino acid, the base substitution does not affect protein structure or function -the amino acid sequence is altered after the site of the mutation, completely changing the structure and function of the polypeptide -the effect on protein function may be neutral or negative, depending on how similar the substituted amino acid is to the original
translation is terminated where the mutation occurs, producing a truncated polypeptide which is unlikely to function correctly
which of the following terms describes the movement of a DNA segment from one chromosome to another? -transmutation -transformation -transduction -translocation -transportation
translocation
true/false: new mutations are much more likely to be harmful than beneficial to the individual
true
true/false: the earlier in development a somatic mutation occurs, the larger the patch of tissue that will be affected by that mutation
true
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 -creation of a fusion protein due to chromosomal translocation -insertion of a retrovirus near the gene's promoter -mutation within the gene -abnormal DNA methylation near the gene's promoter
loss of the chromosome that carries the gene abnormal DNA methylation near the gene's promoter mutation within the gene
what type of mutation changes a normal codon to a termination codon? -silent -missense -frameshift -nonsense
nonsense
the original sequence of a DNA molecule is 5'-AACCGGTT-3'. match each mutates sequence with the correct description of the change that occured 5'-AACCCGGTT-3' -base substitution -single base addition -single base deletion
single base addition
What is metastasis? -the conversion of a proto-oncogene to an oncogene -a change in the DNA sequence of a gene -programmed cell death -the spread of cancerous cells through the bloodstream or body fluids
the spread of cancerous cells through the bloodstream or body fluids
consider a germ-line mutation that occurs in a sperm which fertilizes a normal egg to produce a zygote. in the individual that results from this zygote, _________% of the cells will contain the mutation, and _______% of the gametes produced by that individual will carry the mutation
100%; 50%
what is a tumor? -a DNA element that can change locations -a chemical agent that causes mutations -an overgrowth of cells -a mutation in a DNA sequence -a thickening of the epithelium
an overgrowth of cells
the original sequence of a DNA molecule is 5'-AACCGGTT-3'. match each mutates sequence with the correct description of the change that occured 5'-AACCCGTT-3' -base substitution -single base addition -single base deletion
base substitution
tumor-suppressor genes lead to cancer by mutations that: -eliminate their function -increase their expression -convert them to proto-oncogenes -change their location in the genome
eliminate their function
how does a missense mutation cause red blood cells to sickle? -glutamic acid is changed to valine, altering the structure of the hemoglobin protein and causing the hemoglobin subunits to stick to one another -the entire amino acid sequence is changed, rendering the hemoglobin protein nonfunctional -aspartic acid is changed to glutamic acid, preventing the binding of the appropriate subunits to the heme group -glutamic acid is changed to a stop codon, greatly reducing the length of one of the polypeptide subunits, rendering it nonfunctional
glutamic acid is changed to valine, altering the structure of the hemoglobin protein and causing the hemoglobin subunits to stick to one another
a normal proto-oncogene may become an oncogene if it is: -translocated to a diff chromosome -recognized by a DNA repair enzyme -amplified -deleted -mutated
mutated amplified translocated to a diff chromosome
a heritable change in the genetic material of an organism
mutation
what type of mutation has no effect on the amino acid sequence of a polypeptide? -nonsense -silent -neutral -frameshift -missense
silent
genes encoding proteins involved in the regulation of normal cell growth and thus the prevention of cancer are called __________-___________ genes
tumor-suppressor
arrange the steps in a growth factor signaling pathway that promotes cell division in the correct order -an intracellular signal transduction pathway is activated -genes that promote cell division are transcribed -transcription factors in the nucleus are activated -a growth factor binds to a receptor and activates it
a growth factor binds to a receptor and activates it an intracellular signal transduction pathway is activated transcription factors in the nucleus are activated genes that promote cell division are transcribed
amplification of a proto-oncogene can lead to cancer if it increases: -the amount of protein produced -the turnover rate of the protein -the likelihood of apoptosis occuring
the amount of protein produced
genes that normally function to prevent cancerous growth are called: -tumor-suppressor genes -oncogenes -proto-oncogenes
tumor-suppressor genes
what two mechanisms enable a retrovirus to promote cancer? -it may carry an oncogene in its genome -it may cause chromosome loss -it may cause chromosomal translocations -it may insert their DNA near proto-oncogenes -it may carry a tumor-suppressor gene in its genome
it may insert their DNA near proto-oncogenes it may carry an oncogene in its genome
how do somatic mutations affect an individuals offspring? -the mutation does not occur in germ line cells and therefore does not affect offspring -the mutation is present in all cells of the individuals body, including germ line cells. therefore, the mutation is passed to all offspring -the mutation occurs only in the germ line cells and is passed on to half of the individuals offspring -the mutation occurs only in the germ line cells and is passed on to all of the individuals offspring
the mutation does not occur in germ line cells and therefore does not affect offspring
Cancer is characterized by: -uncontrolled cell division -photosensitivity -uncontrolled apoptosis
uncontrolled cell division
