Question

Среди приведенных ниже утверждений выберите правильные При оплодотворении: 1)происходит объединение ядер и органоидов пловых клеток 2)принесенные сперматозоидом митохондрии активно размножаются 3)яйцеклетка поглощает сперматозоид с помощью фагоцитоза 4)хвостик сперматозоида, состоящий из сократительных белков, используется при формировании цитоскелета зиготы 5)в яйцеклетку попадает только ядро сперматозоида, остальные органоиды отпадают

Answer 1

5 утверждение правильное 

Answer 2

Answer in detail. Among the statements below, choose the correct ones for fertilization: 1) the nuclei and organelles of the gametes fuse 2) the mitochondria brought by the spermatozoon multiply actively 3) the egg cell engulfs the spermatozoon by phagocytosis 4) the tail of the spermatozoon, consisting of contractile proteins, is used to form the cytoskeleton of the zygote 5) only the nucleus of the spermatozoon enters the egg cell, the rest of the organelles fall off

The correct answer is 5) only the nucleus of the spermatozoon enters the egg cell, the rest of the organelles fall off. Here is a detailed explanation:

- During fertilization, the spermatozoon penetrates the egg cell by releasing enzymes that digest the protective layer of the egg cell. The spermatozoon then fuses with the plasma membrane of the egg cell and releases its nucleus into the cytoplasm of the egg cell. The tail and the mitochondria of the spermatozoon are left outside and eventually degenerate . - The egg cell and the spermatozoon nuclei are called pronuclei. They move towards each other and fuse to form the nucleus of the zygote. The zygote inherits half of its chromosomes from each parent. The zygote also inherits all of its cytoplasmic organelles from the egg cell, since the spermatozoon does not contribute any organelles to the zygote . - The cytoskeleton of the zygote is formed by the microtubules and microfilaments that are present in the cytoplasm of the egg cell. The cytoskeleton helps in the movement and division of the zygote. The tail of the spermatozoon, which is composed of contractile proteins called flagellin, does not play any role in the formation of the cytoskeleton of the zygote . - Phagocytosis is a process by which a cell engulfs a solid particle or another cell by forming a membrane-bound vesicle around it. Phagocytosis is not involved in fertilization, since the spermatozoon does not enter the egg cell as a whole, but only releases its nucleus into the egg cell cytoplasm .