reproduction

• What is asexual reproduction?

  Asexual reproduction is the process resulting in the production of genetically identical offspring from one parent.
• What does the term 'asexual' mean in the context of reproduction?

  Asexual means 'without sex' and does not involve gametes (sex cells).
• What are the types of asexual reproduction mentioned?

  1. Bacterial reproduction by cell division or fission
  2. Asexual reproduction in fungi
  3. Asexual reproduction in flowering plants (vegetative propagation)
• What are the advantages of asexual reproduction?

  1. Favorable characteristics of parent passed on
  2. Rapid reproduction
  3. Less energy required
  4. No gametes needed
  5. Only one parent required
  6. Offspring grow in the same favorable environment as the parent
• What are the disadvantages of asexual reproduction?

  1. Does not introduce variation, making offspring susceptible to environmental pressures
  2. Offspring lack resistance if the parent has none
  3. Lack of dispersal can lead to competition for resources
• What is sexual reproduction?

  Sexual reproduction is the process involving the fusion of two gametes to form a zygote, producing genetically different offspring.
• What is fertilization in sexual reproduction?

  Fertilization is the fusion of gamete nuclei.
• What is the process that produces gametes?

  The process of cell division that produces gametes is called meiosis.
• Where are male and female gametes found in flowering plants?

  Male gametes are found in pollen grains, and female gametes are present in ovules.
• What is the diploid number of chromosomes in normal body cells?

  The diploid number is the number of chromosomes present in pairs in the nucleus of somatic cells.
• What is the haploid number of chromosomes in gametes?

  The haploid number is half the diploid number, meaning gametes have half the number of chromosomes.
• How many chromosomes do gametes have?

  Gametes have haploid nuclei with 23 chromosomes.
• How many chromosomes does a zygote have?

  A zygote has diploid nuclei with 23 pairs of chromosomes.
• What are the advantages of sexual reproduction?

  1. Produces variation among offspring
  2. Adaptation to new or changed environments
  3. Allows natural selection leading to evolution
  4. Maintains or increases population
  5. Seeds allow dispersal away from the parent plant
• What are the disadvantages of sexual reproduction?

  1. Variation can produce less successful individuals
  2. Slower process with limited offspring
  3. Requires two parents
• What are the main structures of a flower involved in sexual reproduction?

  1. Sepals
  2. Petals
  3. Stamens (male reproductive organs)
  4. Carpels (female reproductive organs)
  5. Receptacle
• What is the function of sepals in a flower?


  Sepals protect the flower when it is in the bud and are often green and smaller than petals.
• What is the role of petals in a flower?

  Petals attract insects to the flower with their bright colors and scents, aiding in pollination.
• What are stamens in a flower?

  Stamens are the male reproductive organs, consisting of a filament and an anther that produces pollen grains.
• What are carpels in a flower?

  Carpels are the female reproductive organs, consisting of an ovary, style, and stigma, with ovules inside the ovary.
• What is the receptacle in a flower?

  The receptacle is the expanded end of the flower stalk to which all flower structures are attached.
• What is pollination?


  Pollination is the transfer of pollen grains from the anther to the stigma.
• What are the types of pollination?

  1. Cross pollination: Pollen transferred from an anther of one plant to a stigma of a different plant.
  2. Self-pollination: Pollen transferred from an anther of the same plant to its stigma.
• What are the implications of self-pollination?

  1. Less variation and reduced gene pool
  2. Less chance for evolution to occur
  3. Well adapted to the environment
  4. One parent required
• What is the term for the expanded end of a flower stalk?

  Receptacle
• What are the characteristics of insect-pollinated flowers?

  • Produce smaller amounts of pollen
  • Pollen grains are often round and sticky or covered in tiny spikes
  • Petals are present, colored, and scented

  
• What are the characteristics of wind-pollinated flowers?

  • Produce larger amounts of smooth, light pollen grains
  • Pollen is easily carried by the wind
  • Petals are absent or small
• Why do wind-pollinated flowers produce large amounts of pollen?


  Because much of the pollen is lost and there is a low chance of it reaching another flower of the same species.
• What is the role of warmth in seed germination?

  Warmth helps speed up the germination process.
• What is the use of water in seedling growth?

  • Activates enzymes in the seed
  • Converts stored starch to sugar and proteins to amino acids
  • Transports sugar from cotyledons to growing regions
  • Expands vacuoles of new cells
  • Maintains turgor of cells
  • Provides water for photosynthesis
  • Transports salts from soil to shoot
• What is the role of oxygen in seed germination?

  Oxygen is used in aerobic respiration, which provides energy for germination.
• What are the three factors required for successful germination?

  Water, oxygen, and warmth.
• What is fertilization in flowering plants?

  Fertilization is the fusion of the male gamete nucleus from the pollen grain with the female nucleus of the egg cell in the ovule.
• Describe the process of fertilization in flowering plants.

  1. Pollen grain absorbs liquid from the stigma.
  2. A pollen tube grows out of the grain.
  3. This tube grows down the style and into the ovary, where it enters a small hole, the micropyle, in an ovule.
  4. The nucleus of the pollen grain travels down the pollen tube and enters the ovule.
  5. The pollen nucleus combines with the egg cell nucleus.
  6. Each ovule needs to be fertilized by a separate pollen grain.
• What happens after fertilization in flowering plants to form a seed?

  1. Zygote forms and divides to produce an embryo.
  2. The embryo consists of a tiny root and shoot with cotyledons.
  3. In dicots, food is transported to cotyledons via phloem.
  4. The ovule wall thickens to form the seed coat (testa).
  5. The ovary enlarges and petals and stamens fall off, becoming a fruit.
• What are the advantages of seed dispersal?

  • Colonizes new areas
  • Reduces intraspecific competition
  • Reduces inbreeding
• What is the definition of fertilization?

  Fertilization is the fusion of gamete nuclei.
• Why is temperature important for seed germination?

  Temperature speeds up most chemical reactions involved in germination.
• What is the primary energy source for the chemical changes in a growing seedling?

  Energy from food reserves
• How does temperature affect chemical reactions in biological processes?

  Temperature speeds up most chemical reactions