INHERITANCE + VARIATION + EVOLUTION

• What process halves the number of chromosomes in gametes?


  Meiosis
• What is the result of combining genes from sexual partners?

  Unique offspring
• What can gene mutations occasionally affect?

  The functioning of animals or plants
• How can a new mutation be beneficial?

  It can lead to increased fitness
• What is the basis for natural selection?

  Variation generated by mutations and sexual reproduction
• What is selective breeding used for?

  To produce livestock with favoured characteristics
• What is the process called when genes are taken from one species and introduced into another?

  Genetic engineering
• What remains controversial despite its potential benefits?

  Genetic modification
• What type of reproduction leads to non-identical cells?

  Sexual reproduction
• What is formed during sexual reproduction?

  Male and female gametes
• What are the gametes in animals?

  Sperm and egg cells
• What does asexual reproduction involve?

  Only one parent
• What is the result of asexual reproduction?

  Genetically identical offspring
• What type of cell division is involved in asexual reproduction?

  Mitosis
• How many gametes are formed from one cell during meiosis?

  Four gametes
• What happens to the number of chromosomes at fertilization?

  It restores the full number
• What is the advantage of sexual reproduction?

  Produces variation in offspring
• How does variation provide a survival advantage?

  Through natural selection
• What is a key advantage of asexual reproduction?

  More time and energy efficient
• What is a disadvantage of sexual reproduction?

  Requires finding a mate
• Which organisms can reproduce both sexually and asexually?

  Malarial parasites and fungi
• What is DNA composed of?

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

  A small section of DNA on a chromosome
• What does the genome of an organism refer to?

  The entire genetic material of that organism
• What is the significance of studying the human genome?

  It helps in understanding diseases
• What are the four bases of DNA?

  A, C, G, and T
• What does a sequence of three bases in DNA code for?

  A particular amino acid
• How does DNA structure affect protein synthesis?

  It controls the order of amino acids
• What is a dominant allele?

  Always expressed if present
• What is a recessive allele?

  Expressed only if two copies are present
• What does it mean if an organism is homozygous?

  It has two identical alleles
• What is the phenotype of an organism?

  The expressed characteristics
• What is the relationship between genotype and phenotype?

  Genotype determines phenotype
• What is polydactyly caused by?

  A dominant allele
• What causes cystic fibrosis?

  A recessive allele
• What do sex chromosomes determine?

  The sex of an individual
• What are the sex chromosomes in females?

  XX
• What are the sex chromosomes in males?

  XY
• What is variation in a population?

  Differences in characteristics among individuals
• What causes genetic variation?

  Inherited genes and environmental conditions