Questions and Answers
What are genetic disorders?
A defect in the structure or number of genes or chromosomes.
What is the role of genetic counselling?
To provide advice, resources, and support to patients at risk of inherited disorders.
What is the study of genetics?
The study of how and why characteristics are inherited.
In humans, each cell contains ______ chromosomes.
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What does a person’s genotype represent?
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What is a homozygous individual?
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Only one faulty gene is needed to cause an autosomal dominant disorder.
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X-Linked dominant inheritance affects only females.
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What is the difference between phenotype and genotype?
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Which of the following statements are true regarding autosomal dominant disorders?
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Study Notes
Genetic Assessment and Genetic Disorders
- Genetic disorders stem from structural or numerical defects in genes or chromosomes.
- Inherited disorders can be passed through generations, emphasizing the importance of genetic counselling for at-risk patients.
- Genetic disorders may remain undetected until fetal testing or birth, while some are severe enough to halt normal fetal growth.
- In vitro fertilization (IVF) allows for genetic examination of embryos to identify single gene or chromosome disorders before implantation.
Nature of Inheritance
- Genes are the fundamental units of heredity, made of DNA, influencing both physical and cognitive traits.
- Cytogenetics focuses on chromosome study via light microscopy to identify chromosomal abnormalities.
Mendelian Inheritance
- In humans, cells generally contain 46 chromosomes (22 pairs of autosomes and 1 pair of sex chromosomes).
- Each spermatozoon and ovum carry 23 chromosomes, contributing to genetic variability.
- Genotype refers to an individual's genetic makeup, while phenotype describes the expressed traits.
Autosomal Dominant and Recessive Patterns
- Dominant and recessive patterns impact how traits and disorders are inherited.
- Autosomal dominant disorders require only one faulty gene for expression; parental genetic contribution influences child risk:
- Two heterozygous parents have a 25% chance for a child to be unaffected, a 50% chance for a child to be a carrier, and a 25% chance for a child to be affected (potentially homozygous dominant, which can be incompatible with life).
- Autosomal recessive disorders necessitate both genes to be faulty for the disorder to manifest, impacting offspring probability.
Types of Genetic Inheritance
- Autosomal Dominant Inheritance:
- Affected individuals have one faulty dominant gene.
- Presence of disorder indicates a direct lineage connection.
- X-Linked Dominant Inheritance:
- Affected individuals inherit the dominant gene from an affected parent.
- All individuals with the gene manifest the disorder due to its dominant nature.
Genome and Chromosome Composition
- A normal human genome comprises approximately 50,000 - 100,000 genes.
- 46 XX configuration denotes a female with a total of 46 chromosomes.
- 46 XY configuration indicates a male with 46 chromosomes.
Key Genetic Terminology
- Homozygous: Two identical genes (e.g., +,+ or -,-).
- Heterozygous: Two different genes (e.g., +,-).
- Genetic counselling provides valuable resources and support for individuals at risk of genetic disorders.
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Description
This quiz focuses on the genetic assessment and counseling for maternal and child health. It covers the basics of genetic disorders, including their structure, chromosomal defects, and inheritance patterns. Ideal for nursing students looking to enhance their knowledge in genetic health considerations.
