Podcast
Questions and Answers
Which term describes a permanent change in the DNA sequence of a gene?
Which term describes a permanent change in the DNA sequence of a gene?
Which of the following is an example of an autosomal recessive disorder?
Which of the following is an example of an autosomal recessive disorder?
What does a karyotype represent?
What does a karyotype represent?
Nondisjunction during meiosis leads to which of the following?
Nondisjunction during meiosis leads to which of the following?
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Which inheritance pattern requires one mutated gene from either parent to cause a disorder?
Which inheritance pattern requires one mutated gene from either parent to cause a disorder?
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Which of the following best defines a genome?
Which of the following best defines a genome?
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What is the primary factor in multifactorial inheritance disorders?
What is the primary factor in multifactorial inheritance disorders?
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A carrier for a genetic disorder is defined as an individual who:
A carrier for a genetic disorder is defined as an individual who:
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Which chromosomal disorder is characterized by the presence of an extra chromosome leading to specific physical and intellectual disabilities?
Which chromosomal disorder is characterized by the presence of an extra chromosome leading to specific physical and intellectual disabilities?
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What major factor influences the severity of teratogenic effects during fetal development?
What major factor influences the severity of teratogenic effects during fetal development?
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Which of the following teratogens is specifically linked to causing microcephaly and congenital heart defects?
Which of the following teratogens is specifically linked to causing microcephaly and congenital heart defects?
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In which of the following periods of fetal development would exposure to teratogens most likely result in organ-specific malformations?
In which of the following periods of fetal development would exposure to teratogens most likely result in organ-specific malformations?
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Which disorder results from a numerical chromosomal abnormality where one chromosome is missing?
Which disorder results from a numerical chromosomal abnormality where one chromosome is missing?
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Which congenital anomaly is specifically described as a structural abnormality associated with neural tube defects?
Which congenital anomaly is specifically described as a structural abnormality associated with neural tube defects?
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Which of the following maternal factors is associated with the increased risk of congenital heart defects?
Which of the following maternal factors is associated with the increased risk of congenital heart defects?
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Which condition is characterized by the accumulation of excess iron in the body leading to multiple health issues?
Which condition is characterized by the accumulation of excess iron in the body leading to multiple health issues?
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What is the primary genetic mechanism by which mitochondrial inheritance disorders are transmitted?
What is the primary genetic mechanism by which mitochondrial inheritance disorders are transmitted?
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Which of the following conditions is a result of trisomy involving chromosome 13?
Which of the following conditions is a result of trisomy involving chromosome 13?
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Study Notes
Genetic and Chromosomal Disorders
- Genetic and chromosomal disorders stem from abnormalities in DNA structure or chromosome numbers.
- The human genome comprises approximately 3 billion base pairs.
- DNA errors can lead to developmental issues, disorders, and sometimes embryonic failure.
Basic Genetic Terminology
- Gene: A DNA segment encoding a specific protein.
- DNA (Deoxyribonucleic Acid): The genetic material guiding all life processes.
- Genome: The complete set of an organism's DNA.
- Chromosome: A DNA-protein complex within the cell nucleus.
- Karyotype: An organized chart of chromosomes by size and shape.
- Phenotype: Observable characteristics resulting from genotype and environment.
- Genotype: The complete set of genes influencing a specific trait.
- Mutation: A permanent DNA change potentially causing disorders.
- Nondisjunction: Chromosome separation failure during cell division.
- Carrier: An individual carrying one normal and one defective gene allele.
Types of Genetic Disorders
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Single-Gene Inheritance Disorders: Caused by single-gene mutations.
- Autosomal Dominant: One mutated gene from either parent is sufficient.
- Autosomal Recessive: Requires two mutated gene copies, one from each parent.
- X-Linked Inheritance: The gene mutation is on the X chromosome, more commonly affecting males. Examples include Cystic Fibrosis, Sickle Cell Anemia, and Marfan Syndrome.
- Multifactorial Inheritance Disorders: Stem from interacting genetic and environmental factors. Examples include heart disease, diabetes, and cancer.
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Chromosomal Abnormalities: Result from changes in chromosome numbers or structure.
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Numerical Abnormalities:
- Monosomy: Missing a chromosome. Example: Turner Syndrome.
- Trisomy: Extra chromosome. Example: Down Syndrome (Trisomy 21).
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Numerical Abnormalities:
- Mitochondrial Inheritance Disorders: Mutations in mitochondrial DNA inherited solely from the mother. Examples include Leber's Hereditary Optic Neuropathy (LHON) and MELAS Syndrome.
Common Chromosomal Disorders
- Down Syndrome (Trisomy 21): Intellectual disability, facial features, developmental delays.
- Edwards Syndrome (Trisomy 18): Severe intellectual disability, heart defects, physical abnormalities.
- Patau Syndrome (Trisomy 13): Severe developmental issues, brain abnormalities, multiple birth defects.
Teratogens, Congenital Abnormalities, and Abnormal Metal Absorption
- Teratogen: An environmental factor causing developmental abnormalities in a fetus.
- Factors Influencing Teratogenicity:
- Genotype of the conceptus: Genetic makeup can affect susceptibility.
- Timing of exposure: Before germ layer differentiation: potential embryonic death. During organogenesis: organ-specific malformations. Fetal period: growth retardation, impairments.
- Dose and interactions: Higher doses, combined factors, result in heightened negative impact.
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Common Teratogens and Effects:
- Drugs: Alcohol (microcephaly, heart defects, facial anomalies), Phenytoin (cleft lip/heart defects), Vitamin A (spina bifida).
- Infections: Rubella (microcephaly, cataracts, heart defects), Toxoplasma (hydrocephalus), Varicella (limb defects, skin scarring).
- Maternal Factors: Diabetes (neural tube defects, congenital heart defects), Phenylketonuria (microcephaly, heart problems).
- Physical Agents: Hyperthermia (neural tube defects), X-rays (microcephaly, developmental delays).
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Congenital Anomalies: Structural or functional birth defects due to prenatal development problems.
- External Anomalies: Cleft lip/palate, Spina bifida, Clubfoot.
- Internal Anomalies: Heart defects (e.g., Tetralogy of Fallot, Pulmonary Valve Atresia).
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Disorders of Metal Metabolism:
- Hemochromatosis: Excess iron absorption leading to organ damage (liver, heart, pancreas).
- Wilson's Disease: Copper buildup in organs (liver, brain, eyes) causing organ damage.
- Alpha-1 Antitrypsin Deficiency: Abnormal protein buildup in the liver and lungs leading to lung and liver problems.
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Description
Explore the fundamentals of genetic and chromosomal disorders, including terminology, DNA structure, and implications of mutations. This quiz covers key concepts such as genes, mutations, and karyotypes, providing a comprehensive understanding of how these elements influence development and health.
