Questions and Answers
What is the primary role of DNA in genetics?
During which stage of prenatal development does the blastocyst form?
Which process is responsible for creating gametes with half the number of chromosomes?
What is the significance of the SRY gene in prenatal development?
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Which of the following is a recessive genetic disorder?
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How do polygenic traits differ from single-gene traits?
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What is the primary focus of genetic counselling?
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Which chromosomal disorder is associated with an extra twenty-first chromosome?
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What is the purpose of amniocentesis in prenatal diagnosis?
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In the context of genetics, what does the term 'range of reaction' refer to?
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How do dominant gene disorders differ from recessive gene disorders?
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What is the role of the placenta during prenatal development?
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Which prenatal diagnostic technique carries the lowest risk of miscarriage?
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What is an example of a sex-linked recessive trait?
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What does the term 'genomic imprinting' refer to in genetics?
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Study Notes
Genetic Information and Development
- DNA stores genetic information, directing cellular activities and functioning as the blueprint for life.
- The blastocyst forms during the germinal stage of prenatal development, marking successful implantation into the uterine wall.
Gamete Formation
- Meiosis is the process that creates gametes (sperm and eggs) with half the normal number of chromosomes, essential for sexual reproduction.
SRY Gene Importance
- The SRY gene is crucial in prenatal development as it triggers the formation of male sex organs.
Genetic Disorders
- Cystic fibrosis is a recessive genetic disorder, requiring both copies of the gene to be mutated for the disease to manifest.
- Polygenic traits are influenced by multiple genes and environmental factors, contrasting with single-gene traits that arise from one gene.
Genetic Counseling
- The primary focus of genetic counseling is assessing the risk of genetic disorders, aiding parental decision-making without offering cures.
Chromosomal Disorders
- Down syndrome is associated with the presence of an extra twenty-first chromosome, leading to various physical and cognitive challenges.
Prenatal Diagnostic Techniques
- Amniocentesis is used to detect chromosomal abnormalities in the fetus and carries a higher miscarriage risk compared to ultrasound, which has the lowest risk.
Understanding Genetic Traits
- The term "range of reaction" describes potential phenotypes influenced by genetic and environmental interactions.
- Dominant gene disorders manifest with just one copy of the mutated gene from either parent, differing from recessive disorders which require both copies to be affected.
Role of the Placenta
- The placenta serves as a vital organ that facilitates nutrient and waste exchange between the mother and fetus, also producing hormones needed for fetal growth.
Prenatal Techniques and Traits
- Ultrasound is the diagnostic technique with the lowest risk of miscarriage, used primarily for monitoring fetal development.
- Haemophilia is an example of a sex-linked recessive trait, often associated with males due to its inheritance pattern.
Genomic Imprinting
- Genomic imprinting refers to the differential expression of a gene based on whether it is inherited from the mother or father, impacting development and phenotype.
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Description
Test your knowledge on the fundamental concepts of genetics, including DNA's role, prenatal development stages, and gamete formation. This quiz covers essential topics that are pivotal for understanding heredity and biological processes.
