Cell Cycle and Cell Division
Meiosis
Meiosis ek special division hai jo chromosome number aadha karta hai aur chaar cells banata hai, har ek alag. Isi tarah body eggs aur sperm banati hai.
Meiosis me sirf ek baar DNA copy hone ke baad do rounds ki division hoti hai. Pehla round chromosome pairs ko alag karta hai, number aadha karta hai. Doosra round copies ko alag karta hai, mitosis ki tarah. Result: chaar cells, har ek me aadhe chromosomes (haploid).
Do cheezein chaar cells ko alag banati hain: chromosomes tukde swap karte hain (crossing over), aur pairs randomly line up karte hain. Isi mixing ki wajah se siblings identical nahi hote.
Yahaan students galti karte hain
Meiosis chromosome number aadha karta hai aur do divisions chahiye, ek nahi. Students aksar pehli division ke baad ruk jaate hain ya bhool jaate hain ki number aadha hota hai. Ek copying step, do divisions, chaar haploid cells jo sab alag hain.
Yaad rakho
Ek copy, do divisions, chaar alag half-sets.
Exam me kaise kaam aata hai: crossing over, do divisions, aur 'chaar haploid cells' high-yield hain.
Ye kahaan jud'ta hai
Meiosis me chromosome pairs ka alag hona bilkul Mendel ke Law of Segregation ka real cells me hona hai. Genetics ka abstract rule jo tumne padha, wo yahi physical step hai.
Segregation ke peeche ka rule →Ek quick check
Meiosis ek starting cell se kitni cells banata hai, aur kis chromosome number ke saath?
- ADo cells, same number
- BDo cells, aadha number
- CChaar cells, aadha number
- DChaar cells, same number