Ch 11-3 Flashcards
What is pedigree analysis
A study of a particular trait(s) over generations.
What do vertical lines represent in a pedigree?
They connect one generation to the next
What do horizontal lines represent in a pedigree?
They connect related individuals or individuals who have crossed/reproduced.
What are recessively inherited disorders?
Disorders caused by recessive alleles that code for malfunctioning or absent proteins.
What is a carrier?
A heterozygous individual who carries a recessive allele but does not express the disorder phenotypically
How does consanguinity affect the likelihood of recessive disorders?
It increases the likelihood due to the shared genetic histories of close relatives.
Describe sickle-cell disease
A disorder where a single amino acid change in hemoglobin causes red blood cells to deform.
Why is the sickle-cell allele maintained in some populations?
Heterozygotes have a survival advantage against malaria.
Describe cystic fibrosis.
A lethal genetic disease caused by mutations in a gene encoding a transmembrane protein that transports chloride ions.
What are dominantly inherited disorders?
Disorders caused by dominant alleles, often rare and resulting in decreased reproductive success.
Describe Huntington’s disease.
A neurodegenerative disorder with symptoms appearing later in life (35-40 years old).
What are multifactorial disorders?
Disorders with both genetic and environmental components.
What is genetic counseling?
Counseling provided to couples with family histories of genetic disorders to assess the risk of passing on the disorder to their offspring.
What is the probability of two carriers of a recessive disorder having a child with the disorder?
1/4
What are the ethical implications of genetic screening?
The ability to screen for and potentially alter genetic abnormalities raises significant ethical concerns.
What type of inheritance pattern is represented by a 1:2:1 genotypic ratio and a phenotypic spectrum in the population?
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A) Complete dominance
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B) Incomplete dominance
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C) Codominance
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D) Sex-linked inheritance
B
Which of the following is NOT a difficulty in studying human heredity?
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A) Long generation time
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B) Few offspring
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C) Ease of setting up specific matings
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D) Ethical considerations
C
What term describes an individual with more than the usual number of digits?
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A) Polydactyl
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B) Pleiotropic
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C) Consanguineous
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D) Heterozygous
A
Which of the following is an example of a recessively inherited disorder?
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A) Polydactyly
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B) Sickle-cell disease
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C) Huntington’s disease
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D) Achondroplasia
B
The frequency of alleles for serious disorders is typically low due to:
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A) Reduced reproduction by homozygous individuals.
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B) High mutation rates.
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C) Lack of carriers in the population.
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D) Migration patterns.
A
Mating between close relatives is called:
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A) Polydactyly
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B) Pleiotropy
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C) Consanguinity
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D) Heterozygosity
C
Sickle-cell disease is caused by:
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A) A bacterial infection.
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B) A single amino acid change in hemoglobin.
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C) Environmental factors.
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D) Multiple gene mutations.
B
Heterozygotes for the sickle-cell allele have an advantage in areas with:
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A) Cold climates.
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B) High altitudes.
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C) High incidence of malaria.
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D) Low population densities.
C
Cystic fibrosis affects which transmembrane protein?
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A) Sodium channels
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B) Potassium pumps
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C) Chloride transporters
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D) Glucose receptors
C
What term describes a gene product with multiple effects on the body system?
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A) Polydactyl
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B) Pleiotropic
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C) Consanguineous
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D) Heterozygous
B
Which of the following is an example of a dominantly inherited disorder?
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A) Cystic fibrosis
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B) Sickle-cell disease
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C) Achondroplasia
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D) Tay-Sachs disease
C
Huntington’s disease is characterized by:
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A) Early onset symptoms.
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B) Deterioration of the nervous system.
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C) A cure with current therapies.
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D) A bacterial infection.
B
Multifactorial disorders are influenced by:
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A) Only genetic factors.
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B) Only environmental factors.
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C) Both genetic and environmental factors.
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D) Neither genetic nor environmental factors.
C
If both parents are carriers of a recessive disorder, what is the probability of their child inheriting the disorder?
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A) 0%
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B) 25%
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C) 50%
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D) 100%
D
Genetic counseling can help couples:
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A) Choose the gender of their child.
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B) Prevent all genetic disorders.
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C) Assess the risk of passing on genetic disorders.
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D) Guarantee a healthy child.
C
Pedigree analysis can be used to determine the likelihood of a particular genotype/phenotype being present in offspring.
T
Carriers of recessive disorders always exhibit symptoms of the disorder
F
The frequency of specific genetic disorders is consistent across all populations.
F
Consanguinity decreases the likelihood of homozygous recessive traits.
F
Sickle-cell disease provides resistance to malaria in individuals with two copies of the sickle-cell allele.
F
Cystic fibrosis is caused by a buildup of mucus in the lungs and other organs
T
Dominantly inherited disorders are always lethal.
F
Huntington’s disease is a curable genetic disorder.
F
Multifactorial disorders are influenced by multiple genes and environmental factors.
T
Genetic counseling is only available for couples who are already pregnant.
F
