Reproduction Flashcards
Sexual Reproduction
Any multicellular organism that involves the fusion of two gametes (from each parent) to form a zygote
Diploid
Full set of genetic information in an organism (46 for humans)
Haploid
Half a set of genetic information in an organism (23 for humans)
Advantages of sexual reproduction
- All offspring are different (variation)
- Species can adapt to the new environment
- A disease is less likely to effect the individual’s in a population
Disadvantages of sexual reproduction
- Need to find a mate (requires time and energy so few offspring are produced)
- Needs two people
Zygote
A diploid cell resulting from the fusion of two haploid gametes. A fertilised ovum
Mitosis
Produces diploid ‘daughter’ cells that are genetically identical to their parents
Advantages of asexual reproduction
- Only one parent is needed
- Faster than sexual reproduction
- Population can increase rapidly
- Requires less energy
Disadvantages of asexual reproduction
- It does not lead to variation in the population
- The species may be only suitable for one habitat
- Disease effects all individuals in the population
Meiosis
- Sexual reproduction, a form of cell division in the formation of gametes
- Genetically different
- 2 parents
- Produces 4 cells (chromosome number is halved)
- 2 divisions
What does meiosis produce?
-Produces haploid non-identical sex cells called gametes. These fuse to form a diploid fertilised egg.
- In animals it produces sperm and egg cells
- In plants it produces pollen and egg cells
Mitosis
- Asexual reproduction
- Genetically identical
- 1 parent
- Produces 2 cells
- 1 division
What is mitosis used for?
Growth, Repair, Replace
What are gametes)
- Sex cells such as egg or sperm cells
- They are haploid (half genetic information)
Where does Meiosis occur?
Occurs in reproductive organs
Where does mitosis occur?
-Everywhere in the body
What must occur prior to meiosis?
Interphase
First stage of meiosis
- Chromosomes line up along the equator
- Pairs of chromosomes are separated and move to opposite poles of cell (random for variation)
- Chromosome number is halved
Second stage of meiosis
- Chromosomes line up along equator
- Chromosomes separate randomly to opposite poles
- Four unique haploid cells are produced
Why is meiosis important for sexual reproduction
- Increases genetic variation
- Ensures that resultant zygote is diploid
Asexual reproduction
- Produces genetically identical offspring known as daughter cells (clones)
- Involves mitosis
What is a chromosome
A linear DNA molecule tightly coiled around proteins
Why is mitosis important in gametes
- Asexual Reproduction
- Growth
- Repair of damaged cells
- Cell replacement
Four stages of mitosis
Prophase
Metaphase
Anaphase
Telophase
Gametes in a plant
Pollen- Produced by anther
Ova- Produced in the ovules
Cross pollination
The transfer of pollen from the anther of one flower to the stigma of another plant
Self-Pollination
When the pollen from a flowers anther is deposited on the stigma of the same flower