Inheritance, Variation and Evolution

• What is a characteristic of asexual reproduction in plants?

  It involves only one parent.
• Why does asexual reproduction not involve gametes?

  There is no mixing of genetic information.
• What type of offspring does asexual reproduction produce?

  Genetically identical offspring (clones).
• What process is involved in asexual reproduction?

  Mitosis.
• How do strawberry plants reproduce asexually?

  They send out runners that grow new plants.
• How do daffodils reproduce asexually?

  They produce smaller bulbs that grow new plants.
• How do many fungi reproduce asexually?

  By spores.
• How do malarial protists reproduce asexually?

  When they are in the human host.
• What is the role of gametes in sexual reproduction?

  They fuse to create genetic variation.
• What are the male and female gametes in animals?

  Sperm and egg cell.
• What are the male and female gametes in flowering plants?

  Pollen and egg cell.
• What is the result of the fusion of gametes?

  It produces variation in the offspring.
• What process forms gametes?

  Meiosis.
• What happens to chromosomes during meiosis?

  They halve in number to form gametes.
• What is the result of meiosis?

  Four haploid cells (gametes).
• Why is meiosis important for fertilization?

  It restores the full number of chromosomes.
• How many chromosomes does a fertilized egg cell have?

  46 chromosomes (23 pairs).
• What is the genetic material in the nucleus of a cell?

  DNA.
• What are chromosomes made of?

  DNA.
• What is a gene?

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

  A specific sequence of amino acids.
• What is the genome of an organism?

  The entire genetic material of that organism.
• What can studying the human genome help with?

  Understanding inherited disorders and treatments.
• What is polydactyly caused by?

  A dominant allele.
• What is cystic fibrosis caused by?

  A recessive allele.
• What is the risk of embryonic screening tests?

  False positives or negatives may occur.
• What determines sex in humans?

  Sex chromosomes.
• What are the sex chromosomes in females?

  Two identical X chromosomes (XX).
• What are the sex chromosomes in males?

  One X and one Y chromosome (XY).
• How do offspring inherit sex chromosomes?

  One from each parent.
• What happens if an X sperm fertilizes an egg?

  A girl is produced.
• What happens if a Y sperm fertilizes an egg?

  A boy is produced.
• What is variation in individuals?

  Differences in characteristics.
• What causes genetic variation?

  Differences in inherited genes and environment.
• What is the only source of new alleles?

  Mutations.
• What are mutations?

  Permanent changes in DNA.
• What is the rate of mutations in organisms?

  Very low rate.
• What is the effect of most mutations on phenotype?

  They often have no effect.
• What is the significance of harmful mutations?

  They can be detrimental to survival.
• What is the significance of useful mutations?

  They can provide advantages for survival.