Topic 6 - inheritance

• What is meiosis?

  Formation of four non-identical cells
• What is mitosis?

  Formation of two identical cells
• What does sexual reproduction involve?

  Joining of male and female gametes
• What are the gametes in animals?

  Sperm and egg cells
• What are the gametes in flowering plants?

  Pollen and egg cells
• How are gametes formed?

  By meiosis, as they are non-identical
• How many chromosomes does a normal cell have?

  46 chromosomes
• How many chromosomes are in a gamete cell?

  23 chromosomes
• What happens to gametes during fertilization?

  They fuse to form a cell with 46 chromosomes
• What is the result of sexual reproduction?

  Variation in the offspring
• What does asexual reproduction involve?


  One parent with no gametes joining
• How are cells formed in asexual reproduction?

  By mitosis, forming two identical cells
• What is the genetic outcome of asexual reproduction?

  No mixing of genetic information
• What are clones?

  Genetically identical organisms
• Which organisms reproduce asexually?

  Bacteria, some plants, and some animals
• What happens to chromosomes during meiosis?

  They are shuffled, producing genetic variation
• What is the chromosome number in gametes?

  Each gamete has 23 chromosomes
• What happens after fertilization?

  The cell divides by mitosis to produce many copies
• What is differentiation?

  Cells take on different roles after division
• What are the advantages of sexual reproduction?

  • Produces variation in offspring
  • Increases survival advantage in changing environments
  • Decreases extinction risk for the species
• What are the advantages of asexual reproduction?

  • Only one parent needed
  • Faster reproduction without finding a mate
  • Produces many identical offspring in favorable conditions
• What is DNA?

  A polymer containing genetic instructions
• What is the structure of DNA?

  Two strands forming a double helix
• What are chromosomes made of?

  Long strands of DNA
• What are the four nitrogenous bases in DNA?

  A, C, G, T
• What is a gene?

  A section of DNA coding for a protein
• What does the genome refer to?

  All genes coding for proteins in an organism
• How has studying the human genome helped medicine?

  Improved understanding of diseases and treatments
• What does DNA stand for?

  Deoxyribonucleic acid
• What are nucleotides?

  Small parts that make up DNA
• What forms the backbone of DNA?

  Sugar and phosphate molecules
• What is complementary base pairing?

  A pairs with T, C pairs with G
• What does the order of bases in DNA determine?

  The type of protein produced
• What is protein synthesis?

  Producing a protein from DNA
• What happens to DNA during protein synthesis?

  It cannot move out of the nucleus
• What is mRNA?

  A template of the original DNA
• How are amino acids brought to ribosomes?

  By carrier molecules
• What happens when the amino acid chain is complete?

  The protein folds into a unique 3D structure
• What are enzymes?

  Biological catalysts that speed up reactions
• What can mutations do to DNA?

  Change the sequences of bases