reproduction

• What are the two main types of reproduction?

  Sexual and asexual reproduction
• What are the characteristics of sexual reproduction?

  • Involves two parents
  • Cell division through meiosis
  • Joining of male and female gametes
  • Produces non-identical offspring
  • Results in genetic variation
• What are the characteristics of asexual reproduction?

  • Involves one parent
  • Cell division through mitosis
  • No fusion of gametes
  • Produces genetically identical offspring
  • No mixing of genetic information
• What is meiosis?

  A type of cell division that makes gametes
• What happens to the number of chromosomes during meiosis?

  It halves in gametes
• What restores the number of chromosomes after meiosis?

  Fertilisation
• What process follows fertilisation in the development of an embryo?

  Mitosis produces more cells
• What is the process of meiosis summarized?

  1. Parent cell
  2. DNA replicates
  3. Two daughter cells with paired chromosomes
  4. Four daughter cells (gametes) with single chromosomes
  5. All genetically different
• What is the genetic material in the nucleus of a cell composed of?

  DNA
• What structure contains DNA in a cell?

  Chromosomes
• What is a gene?

  A section of DNA coding for a protein
• What is the genome of an organism?

  The entire genetic material of that organism
• What can scientists do by studying the human genome?

  • Search for disease-linked genes
  • Understand and treat inherited disorders
  • Trace human migration patterns
• What causes polydactyl disorder?

  A dominant allele
• What causes cystic fibrosis?

  A recessive allele
• What are the ethical issues surrounding embryo screening and gene therapy?

  Concerns about genetic modification and selection
• What is a gamete?

  • Specialized sex cell
  • Formed by meiosis
• What are chromosomes?

  • Long DNA molecules
  • Found in the nucleus of cells
• What is an allele?

  Different forms of the same gene
• What is a dominant allele?

  Needs one copy to be expressed
• What is a recessive allele?

  Needs two copies to be expressed
• What does homozygous mean?

  Two copies of the same allele
• What does heterozygous mean?

  Two different alleles for a trait
• What is a genotype?

  Combination of alleles an individual has
• What is a phenotype?

  Physical expression of the genotype