LV Cell division IGNORE FOR NOW Flashcards
Name the two types of reproduction
- Asexual reproduction
- Sexual reproduction
Define asexual reproduction
- Asexual reproduction involves only one parent and no fusion of gametes
- There is no mixing of genetic information
- This leads to genetically identical offspring (clones)
- Only mitosis is involved
Define sexual reproduction
- Reproduction that involves two parents
- It involves the mixing of genetic information
- This leads to variety in the offspring
- The formation of gametes involves meiosis
- It involves the fusing of gametes
State the 2 types of gametes that are involved in sexual reproduction in animals
- sperm
- ova (egg cells)
State the 2 types of gametes that are involved in sexual reproduction in flowering plants
- pollen
- ova (egg cells)
Give 3 advantages of sexual reproduction
- Produces variation in the offspring
- If the environment changes variation gives a survival advantage by natural selection
- Natural selection can be sped up by humans in selective breeding to increase food production
Give 4 advantages of asexual reproduction
- Only one parent needed
- More time and energy efficient as do not need to find a mate
- Faster than sexual reproduction
- Many identical offspring can be produced when conditions are favourable
Name 3 organisms that reproduce by both asexual and sexual reproduction depending on the circumstances
- Malarial parasites
- Fungi
- Plants e.g. strawberry plants
State how malarial parasites demonstrate both sexual and asexual reproduction
Malarial parasites reproduce asexually in the human host, but sexually in the mosquito
State how fungi demonstrate both sexual and asexual reproduction
- Many fungi reproduce asexually by spores
- They also reproduce sexually by spores to give variation
Remember: fungal spores can be produced asexually and sexually
Explain why it is an advantage for fungi to be able to produce spores asexually and sexually
- When conditions are favourable the fungi can produce spores asexually to make many identical spores in a short period of time
- When conditions are unfavourable fungi can produce spores sexually to make genetically different spores to increase the chances of surviving the environmental conditions
State how some plants demonstrate both sexual and asexual reproduction
- Flowering plants produce seeds sexually
- They also reproduce asexually by runners such as strawberry plants, or bulb division such as daffodils
State the type of cell division involved in asexual reproduction
Mitosis
State the type of cell division involved in sexual reproduction
Meiosis
Which type of reproduction involves the production of haploid gametes
Meiosis
State the term that describes the fusing of two gametes to form a zygote
Fertilisation
How many chromosomes are found in a gamete?
- Half the full number i.e. haploid (n)
- For human cells this is 23