2.3 Making gametes
Meiosis
- Process of cell division that produces gametes; sperms and eggs.
- Gametes = sex cells
- Eggs are produced in ovaries of female reproductive system
- Sperms are produced in testes of male reproductive system
What would happen if parents pass their complete set of genetic information?
* Offspring would have 4n chromosomes and then the next generation would have
8n and so on.
*By halving the number of chromosomes in gametes, the number of chromosomes
from generation to generation is kept constant as 2n.
-One chromosome from each homologous pair of chromosomes must end up in each
gamete that is produced : Giving haploid number of chromosomes --> n (23
chromosomes)
-Female sex chromosomes are a homologous pair --> XX
- Male sex chromosomes are not homologous, but they behave as a pair during
meiosis--> XY
-Just like mitosis, chromosomes replicate in preparation for division.
, -Spindle fibers form at right
angles to the first.
- New nuclear membrane forms
and cytoplasm divides to produce 4
new cells.
Sexual reproduction
-Creates variation in population.
- It is the role of male and female reproductive system to ensure that;
-->Male and female gametes meet.
-->Fertilization takes place.
-->New individual has the best chances of survival.
Meiosis in plants
- Female gametes are produced in the ovary to make haploid ovules.
- Male gametes are produced in flower’s anther to make haploid pollen.
Meiosis
- Process of cell division that produces gametes; sperms and eggs.
- Gametes = sex cells
- Eggs are produced in ovaries of female reproductive system
- Sperms are produced in testes of male reproductive system
What would happen if parents pass their complete set of genetic information?
* Offspring would have 4n chromosomes and then the next generation would have
8n and so on.
*By halving the number of chromosomes in gametes, the number of chromosomes
from generation to generation is kept constant as 2n.
-One chromosome from each homologous pair of chromosomes must end up in each
gamete that is produced : Giving haploid number of chromosomes --> n (23
chromosomes)
-Female sex chromosomes are a homologous pair --> XX
- Male sex chromosomes are not homologous, but they behave as a pair during
meiosis--> XY
-Just like mitosis, chromosomes replicate in preparation for division.
, -Spindle fibers form at right
angles to the first.
- New nuclear membrane forms
and cytoplasm divides to produce 4
new cells.
Sexual reproduction
-Creates variation in population.
- It is the role of male and female reproductive system to ensure that;
-->Male and female gametes meet.
-->Fertilization takes place.
-->New individual has the best chances of survival.
Meiosis in plants
- Female gametes are produced in the ovary to make haploid ovules.
- Male gametes are produced in flower’s anther to make haploid pollen.
