EXAM 3 Flashcards
Diabetes involves both genetic and environmental factors, yet one either develops the disease or doesn’t develop the disease, diabetes is an example of a multifactorial…
threshold trait
A trait like weight in people shows a…. distribution of phentoypes
continuous
The round pea shape in Mendel’s work is a good examples of a……
discontinuous (or single gene) trait
People with an inherited predisposition to retinoblastoma inherit …. defective alleles of the RB gene
one
The ability of cancer cells to move from the original tumor to a new site is called
metastasis
The major type of damage in DNA that is produced by UV light is
TT dimers
The principle cause of skin cancer is exposure to
sunlight
Fragile-X syndrome is an example of a disorder caused by what types of mutation
trinucleotide repeat
IF the phenotype of a trait is half due to genetics and half due to the environment, then the heritability of the trait is nearly
about 1/2
Small molecule released into synapses during nerve impulses are
neurotransmitters
In Huntington disease loss of neurons is due to the toxic effects of the
huntingtin protein
Most human behaviors are… traits that are influenced by both genetic and environmental factors
multifactoral
A neurological disease arising from high numbers of a CAG trinucleotide repeat is…
Huntington Disease
A gene whose enzyme produce is involved in the metabolism of neurotransmitters is
MAOA
If a pair of identical twins share a trait, then the trait is
concordant
If the heritability of the trait is near…. then the trait has almost no genetic component
zero
Viruses that cause cancer typically carry … as part of their genomes
oncogenes
What mutation in the ras proto-oncogene will change the gene to an oncogene and produce a RAS protein that differs from the normal gene by one amino acid
missense
The RB and p53 genes are good examples of … since they act to limit progression from G1 to S
tumor suppressor genes
A carcinogen and mutagen that is produced by fungal cells is
aflatoxin
Over the last 60 years the average IQ of children in the United States has steadily increased. What is a reasonable explanation for this trend?
The environment has changed in ways that increase the average IQ’s of the children
Our text discuessed examples of differential sensitivity among humans to drugs and chemicals in teh environment. What are four examples of these examples?
- The range of sensitivities found reflects differences in the nucleotide sequences of genes
- The range of sensitivities found reflects differences in the amino acid sequences of proteins
- The range of sensitivities found reflects differences in the active sites of proteins
- The range of sensitivities found reflects differences in genotypes
DNA rearrangements can dramatically change the expression of genes, what happens to the structure and expression of the c-abl oncogene after a reciprocal translocation generates the ‘Philadelphia Chromosome’ which is associated with a form of leukemia?
The c-abl gene is rearranged to form an active hybrid gene that is expressed in large amounts
What is a type of cancer commonly found in children?
leukemia
Most polygenic traits in people display:
a continuous distribution of the trait’s phenotype
When each of a pair of monozygotic twins exhibits the same trait, it is described as being
concordant
Sporadic retinoblastoma typically
occurs in one eye in adults
Traits where the phenotype depends on the effects of several genes as well as the environment are
multifactoral traits
The Concordance Value for cleft lip for monozygotic twins is 42% and for dizygotic 5%. What does this imply?
The environmental plays a major role in determining the trait
Traits that are determined by two or more genes are known as…
polygenic
For a multifactorial threshold trait like cleft lip, which group is expected to have the greatest ‘familial risk’ relative to the general population?
monozygotic twins
In humans, polygenic traits like weight or height exhibit
a continuous distribution of the phenotype
Mutant ras genes are associated with several forms of cancer. The normal, nonmutant ras gene
is a proto-oncogene
A defect in the X-linked monoamine oxidase type A gene is associated with mild mental retardation, aggression, and violent behavior. What may be true?
The trait is recessive and fewer females than males are affected
What are two things that may cause a predisposition to develop cancer?
- decreasing the expression of a tumor suppressor gene
2. decreasing the expression of a DNA repair gene
In twin studies of male homosexual behavior, if one brother showed homosexual behavior, then 52% of identical twins, 22% of nonidentical twins and 11% of unrelated adoptive brothers also showed homosexual behavior. What is this study consistent with?
There being significant genetic and environmental components to homosexual behavior
Schizophrenia may be related to problems with
producing the myelin membranes found on nerve cells
A human genetic disease that is associated with an increased number of trinucleotide repeats is
huntingtons disease
What enzyme is involved in the natural turnover of neurotransmitters?
monoamine oxidase
Which autosomal dominant trait is associated with progressive neurological decline which usually starts in middle age?
Huntington’s disease
A mutagen on DNA in skin cells, that doesn’t have the energy to mutate DNA in cells within the body, is
UV light
Ultraviolet light damages DNA by causing the formation of
thymine dimers in the DNA
The DNA in skin cells undergoes vast amounts of damage from sunlight. The usual result of this damage is
no effect on the overall cell metabolism because humans possess highly effective DNA repair systems
Metastasis refers to the process in which
tumor cells move to new sites in the body
The most aggressive form of skin cancer is
malignant melanoma
The Philadelphia chromosome was generated by
a translocation
A type of cancer involving over production of white blood cells is
lymphoma
What is associated with defective DNA repair?
an inherited predisposition to colon cancer involving the HNPCC1 gene
The heritability of the total ridge count in human fingerprints in nearly one. What does this imply?
A person’s genotype plays a much greater role than the environment in determining this trait
The principle cause of skin cancer is exposure to ….. in sunlight and tanning beds
UV-LIGHT
Which sex suffers the most from autoimmune diseases
females