Cell Division: Reproduction (paper 2) Flashcards
what are the 2 types of reproduction
- sexual
- asexual
where does asexual reproduction occur
- bacteria
- some plants
- some animals
what are the 5 key things that define asexual reproduction
- involves mitosis / binary fissions** for bacteria
- only 1 parent
- does not involve the fusion of gametes
- does not result in the mixing of genetic information
- produces genetically identical offspring –> clones
what is the asexual process called in plants
vegetative reproduction
Vegetative reproduction does not produced …………, ………………., ………………
- spores
- pollen
- seeds
what are 3 examples of vegetative reproduction
- runners : strawberry plants
- bulbs : daffodils
- tubers : potatoes
what are the advantages of asexual reproduction
- faster process (quicker)
- produces lots more offspring
- 1 parent –> no need fore mate –> easier
what are the advantages of sexual reproduction
- population resistance to disease / harsh environment
- humans can use it in selective breeding
how many parents does sexual reproduction need
2
in which organisms does sexual reproduction occur
- animals
- plants
what are the 5 key things that define sexual reproduction
- needs 2 parents
- requires the fusions of male and female gametes –> process of fertilisation must occur
- mixing of genetic information –> leads to variety in offspring
- offspring are genetically different from both of their parents
what are the gametes call in male and females
- Male: Sperm (in animals), pollen (plants**
- Female: Ova
the formation of gametes invole what type of cell division
meiosis
how many chromosome does a gamete have and what is it called
23 - haploid
describe the stages of fertilisation
- ovum + sperm fuse during fertilisation
- results in a single cell called a zygote –> has full set of chromosomes , diploid cell
- zygote will develop into an embryo by mitosis
- as embryo develops : cells differentiate to form different types of cells + tissues
offspring produced in sexual reproduction have a greater variation than offspring produced by asexual reproduction, why?
process of fertilisation mean that zygote receives half of its genetic information from its mother, half from its father –> embryo inherits characteristics from both parents
where in the body do cell divide by meiosis
reproductive organs to form gametes
reproductive organs include:
- testes and ovaries in animals
- anthers and ovaries in flowering plants
describe the stages of meisosis
- copies of the genetic information are made
- the cell divides twice to form 4 gametes, each with a single set of chromosomes
Advantages of sexual reproduction
- produces genetically varied offspring : if environment changes variation gives a survival advantage by natural
selection - natural selection can be speeded up by humans in selective breeding to
increase food production.
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 genetically identical offspring can be produced when conditions are favourable
what organisms use both sexual and asexual reproduction
- malaria parasite
- fungi
- Plants:
- strawberry plant
- daffodils, onions
- potatoes
how does malaria parasite carry out sexual reproduction and asexual reproduction
- reproduces sexually when it is inside the mosquito (acts as vector)
- reproduces asexually when it is inside human host liver cells
how does fungi carry out sexual reproduction and asexual reproduction
- reproduce spores sexually - these are genetically varied
- also reproduce spores asexually - genetically identical to parent
how does the strawberry plant carry out sexual reproduction and asexual reproduction
Sexual:
- produce gametes (ovules and pollen grains) in flowers which produce seeds as a result of fertilisation
Asexual:
- produce runners - stems which grow horizontally on the surface of the soil and produces new plants genetically identical to the parent plant
how does daffodils and onions carry out sexual reproduction and asexual reproduction
Sexual:
- produce **gametes* in flowers —> seeds produced due to fertilisation
Asexual:
- produce bulbs - new bulbs form on the original parent plant and can split off to form a genetically identical plant
how does potatoes carry out sexual reproduction and asexual reproduction
Sexual:
- produce **gametes* in flowers —> seeds produced due to fertilisation
Asexual
- produces tubers - are underground structures that form on the original parent bulb and ca split off to form a genetically identical plant
