genetics main

• What is genetics?

  Science of inheritance from parents to offspring
• What are alleles?

  Different forms of the same gene
• What does genotype refer to?

  Genetic makeup of an organism
• What does phenotype refer to?

  Physical characteristics of an organism
• What does homozygous mean?

  Both alleles of a gene are the same
• What does heterozygous mean?

  Two alleles of a gene are different
• What is a dominant allele?

  Allele that overrides the recessive allele
• What is a recessive allele?

  Shows in phenotype only if homozygous
• What is a monohybrid cross?

  Genetic cross involving one characteristic
• What did Gregor Mendel investigate?

  Monohybrid crosses using pea plants
• What was special about Mendel's work?

  He discovered principles of inheritance early
• What is a test cross?

  Determines genotype of dominant phenotype
• How is a test cross performed?

  Cross dominant phenotype with homozygous recessive
• What does a recessive phenotype in offspring indicate?

  Parent's genotype is heterozygous
• What is a genetic condition/disorder?

  Condition caused by a fault in a gene
• What is sex linkage?

  Genes on sex chromosomes affecting traits
• How are symbols used in sex-linked genetic crosses?

  Show sex chromosome type and allele
• What is a carrier?

  Heterozygous individual without the condition
• What is genetic screening?

  A process to identify genetic abnormalities
• What is Huntington's disease?

  Progressive brain deterioration, fatal condition
• What is amniocentesis?

  A procedure to obtain fetal cells from amniotic fluid
• How is Huntington's disease inherited?

  It is a dominant condition, not sex-linked
• What risk is associated with amniocentesis?

  Risk of miscarriage
• How can the risk of miscarriage from amniocentesis be reduced?

  By conducting a preliminary blood test
• What is a dilemma associated with positive amniocentesis results?

  Whether to carry out an abortion
• What are some ethical issues of genetic screening?

  • Who decides who will be tested?
  • Dilemma of abortion after positive results
  • Potential discrimination based on genetic information
• What condition do individuals with cystic fibrosis experience?

  Frequent lung infections and gastrointestinal problems
• What type of genetic condition is cystic fibrosis?

  It is a recessive condition
• What is the genetic cause of Down's syndrome?

  Presence of an extra chromosome (3 copies of chromosome 21)
• How does Down's syndrome occur?

  Due to a mistake in gamete formation
• Is Down's syndrome inherited?

  No, it is not inherited
• Who is more likely to have a child with Down's syndrome?

  Older mothers (over 40)
• What are the implications of having an extra chromosome on cognitive development?

  It can lead to reduced cognitive development
• What are the effects of an extra chromosome on muscle tone?

  It leads to reduced muscle tone