Biology Paper 2: B6

• What is the type of nuclear division that produces genetically identical cells?

  Mitosis
• What is the primary purpose of mitosis?

  It is used for growth, repair, and asexual reproduction
• What type of nuclear division produces genetically different cells?

  Meiosis
• What is the role of meiosis in reproduction?

  It is used to produce gametes (sex cells)
• What is sexual reproduction?

  It involves the fusion of the nuclei of two gametes to form a zygote
• What are the gametes of animals?

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

  Pollen cells and egg cells
• What is fertilisation defined as?

  The fusion of gamete nuclei
• What is a key characteristic of offspring produced by sexual reproduction?

  They are genetically different from each other
• What is asexual reproduction?

  It does not involve sex cells or fertilisation
• What is the result of asexual reproduction?

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

  Only mitosis
• What happens to the number of chromosomes during meiosis?

  The number of chromosomes is halved
• Why is meiosis described as a reduction division?

  Because it halves the chromosome number from diploid to haploid

  
• What do we call gametes?

  Haploid cells
• How many haploid cells does meiosis produce?

  Four haploid cells

  
• What is the importance of meiosis in reproduction?

  It increases genetic variation of offspring
• What happens during fertilisation?

  Gametes join to restore the normal number of chromosomes
• What is formed when male and female gametes fuse?

  A zygote (fertilised egg cell)
• What process follows the formation of a zygote?

  The zygote divides by mitosis
• What is cell differentiation?

  The process of cells becoming specialized
• What are the advantages and disadvantages of sexual reproduction?

  Advantages:

  • Increases genetic variation
  • Species can adapt to new environments
  • Disease is less likely to affect the population

  
  

  Disadvantages:

  • Takes time and energy to find mates
  • Difficult for isolated members to reproduce
• What are the advantages and disadvantages of asexual reproduction?

  Advantages:

  • Rapid population increase
  • More time and energy-efficient

  
  

  Disadvantages:

  • Limited genetic variation
  • Vulnerable to changes in conditions
• How do malarial parasites reproduce in humans and mosquitoes?

  They reproduce asexually in humans and sexually in mosquitoes
• How do fungi reproduce?

  Many fungi reproduce both asexually and sexually
• How do some plants reproduce asexually?

  By producing runners or bulb division
• What is the entire set of genetic material of an organism called?

  The genome
• What is DNA?

  DNA is the molecule that contains the instructions for growth and development
• What is the structure of DNA?

  DNA is a polymer made up of two strands forming a double helix

  
• Where are chromosomes located?

  In the nucleus of cells

  
• What is the definition of variation in biology?

  Variation is differences between individuals of the same species.
• What is a gene?

  A gene is a short length of DNA that codes for a protein
• What does each gene code for?

  A particular sequence of amino acids
• What is phenotypic variation?

  Phenotypic variation is the difference in features between individuals of the same species.
• What is the Human Genome Project?

  It was an international effort to determine the DNA sequence of the entire human genome
• What are the two main causes of phenotypic variation?

  Phenotypic variation can be caused by genetic and environmental factors.
• What is genetic variation?

  Genetic variation is controlled entirely by genes.
• What is the significance of the Human Genome Project?

  It improves understanding of genes linked with diseases and helps find treatments
• Give an example of genetic variation in humans.

  Examples include blood group, eye colour, and gender.
• What are nucleotides?

  They are the individual subunits of DNA