P2. Inheritance And Evolution

• What process halves the number of chromosomes in gametes?

  Meiosis
• How does fertilization affect chromosome number?

  It restores the full number of chromosomes
• What do cells in reproductive organs divide to form?

  Gametes
• What happens when a cell divides to form gametes?

  • Copies of genetic information are made
  • The cell divides twice to form four gametes
  • Each gamete has a single set of chromosomes
  • All gametes are genetically different
• What occurs at fertilization regarding gametes?

  Gametes join to restore chromosome number
• What process follows fertilization in the new cell?

  Mitosis
• What happens as the embryo develops?


  Cells differentiate
• What are the advantages of sexual reproduction?

  • Produces variation in offspring
  • Variation provides survival advantage
  • Selective Breeding for food production
• What are the advantages of asexual reproduction?

  • Only one parent needed
  • More time and energy efficient
  • Faster than sexual reproduction
  • Many identical offspring produced
• How do malarial parasites reproduce?

  Asexually in humans, sexually in mosquitoes
• How do many fungi reproduce?

  Asexually by spores and sexually
• How do many plants reproduce?

  Sexually by seeds and asexually by runners
• What is the definition of a genome?

  The entire genetic material of an organism
• What is DNA composed of?

  A polymer made of two strands
• What is a gene?

  A small section of DNA on a chromosome
• What does each gene code for?

  A particular sequence of amino acids
• What is the significance of studying the human genome?

  It helps...

  • search for genes linked to different types of disease

  • understanding and treatment of inherited disorders

  • use in tracing human migration patterns from the past.
• What does a sequence of three bases in DNA code for?

  A particular amino acid
• What is the structure of DNA?

  Two strands forming a double helix
• What is a mutation?

  A change in the DNA sequence
• What can mutations lead to?

  Altered proteins or no effect
• What are the terms related to genetic inheritance?

  • Gamete
  • Chromosome
  • Gene
  • Allele
  • Dominant
  • Recessive
  • Homozygous
  • Heterozygous
  • Genotype
  • Phenotype
• What is a dominant allele?

  An alternative form of a gene that is always expressed.
• What is a recessive allele?

  Expressed only if two copies are present
• What does homozygous mean?

  Two identical alleles for a trait
• What does heterozygous mean?

  Two different alleles for a trait
• What is the relationship between genotype and phenotype?

  Phenotype is the observable expression of this genotype
• What is the role of mutations in variation?

  They create genetic diversity
• What is selective breeding?

  Choosing parents for desired traits
• What can selective breeding lead to?

  Inbreeding and inherited defects
• What are the impacts of selective breeding?

  • Increases desired traits in crops and animals
  • Can lead to inbreeding issues
  • Enhances food production
• What is the significance of genetic engineering?

  Introducing genes from one species to another
• Why is genetic modification controversial?

  Potential ethical and ecological concerns
• What is selective breeding?

  Breeding plants and animals for traits
• Why have humans practiced selective breeding for thousands of years?

  To enhance food crops and domesticated animals
• What is the first step in selective breeding?

  Choosing parents with desired characteristics
• How does selective breeding continue over generations?

  By breeding offspring with desired traits together
• What characteristics can be chosen in selective breeding?

  • Disease resistance in crops
  • Increased meat or milk production in animals
  • Gentle nature in domestic dogs
  • Large or unusual flowers
• What is a potential risk of selective breeding?

  It can lead to inbreeding and diseases
• What is genetic engineering?

  Modifying an organism's genome with genes