B13.1

• What is sexual reproduction

  Type of reproduction that requires the fusion of the nuclei of a female and male gamete ( fertilisation) .
• What are the human gametes?

  Sperm and egg cell
• What are the plant gametes ?

  Pollen and ovule.
• How many chromosomes do human gametes have compared to normal human cells? Why?

  They have half the genetic material making them haploid cells. In human gametes this is 23 chromosomes. This is so that after fertilisation the offspring has the right amount of chromosomes ( diploid - 46 chromosomes )
• What is the process of making gametes?


  Meiosis
• What is asexual reproduction ?

  Type of reproduction that only requires one parent and does not need gametes.
• How is asexual reproduction achieved in plants, fungi and some animals ?

  Mitosis
• How is asexual reproduction achieved in prokaryotic cells like bacteria?


  Binary fission
• What are 2 disadvantages of asexual reproduction ?

  Low genetic variation - offspring more susceptible to disease. Lack of genetic diversity - hard to adapt to the environment.
• Advantages of asexual reproduction

  Only requires one parent - no need to spend time and energy looking for a mate.

  Quick - allows organism to colonise an area more quickly
• 2 downfalls of sexual reproduction

  2 parents required - time and energy required to find a mate

  2 parents required - species spend resources to impress their mates even though it doesn't aid survival. Eg. bright feathers

  This all takes Time .
• Pros of sexual reproduction

  Introduces genetic variation due to the fusion of gametes.

  -Less likely to be wiped out by a disease

  -Easier to evolve and adapt to environment.