What is Vitellogenesis and its significance?

Vitellogenesis (also known as yolk deposition) is the process of yolk formation via nutrients being deposited in the oocyte, or female germ cell involved in reproduction of lecithotrophic organisms. In insects, it starts when the fat body stimulates the release of juvenile hormones and produces vitellogenin protein.

What is Oogenesis and Vitellogenesis?

Vitellogenesis occurs when the oocyte reaches the diplotene stage of meiotic prophase. Yolk is not a single substance, but a mixture of materials used for embryonic nutrition. The major yolk component in frog eggs is a 470-kDa protein called vitellogenin.

What is the meaning of Vitellogenesis?

the process by which the yolk is formed and accumulated in the ovum.

When a egg contains large amount of yolk it is called?

> Option D- Macrolecithal: The egg that have large amount of yolk is called macrolecithal. These eggs have large concentrated yolk, such eggs are found in crocodile, aves, chelonian etc. Hence, the correct answer is option (D).

What is the function of Vitelline membrane?

The vitelline membrane (VM) is a multilayered structure that protects and gives shape to the egg yolk and separates it from the egg white. Together with the chalaza, VM keeps the egg yolk in the central part of the egg, thereby preventing its integration with the shell membranes.

What does Amphimixis mean?

the union of gametes in sexual reproduction
: the union of gametes in sexual reproduction.

Which cell organelle is connected with Vitellogenesis?

In early vitellogenic oocytes, combined activities of the Golgi complex, mitochondria and rough endoplasmic reticulum in the cytoplasm are associated with autosynthetic vitellogenesis.

Is human egg Isolecithal?

In human beings, the eggs are alecithal i.e. they do not contain yolk. Mesolecithal eggs contain moderate amount of yolk e.g., frog. Microlecithal eggs contain a little amount of yolk e.g., Amphioxus.

Is Amphioxus a telolecithal?

Isolecithal or Homolecithal Egg: In isolecithal eggs, the very little amount of yolk present is uniformly distributed throughout the ooplasm (eg. echinoderms, Amphioxus, mammals). Such a type of egg, in which the yolk is concentrated towards one pole, is called telolecithal egg.

Do humans have Vitelline membranes?

It is called zona pellucida in mammals. Between the vitelline membrane and zona pellucida is a fluid filled periviteline space. As soon as the spermatozoon fuses with the ovum, signal transduction occurs, resulting in an increase of cytoplasmic calcium ions….

What do you need to know about vitellogenesis?

Vitellogenesis. From Wikipedia, the free encyclopedia. Jump to navigation Jump to search. Diagram of vitellogenesis in the digenean Crepidostomum metoecus. Vitellogenesis (also known as yolk deposition) is the process of yolk formation via nutrients being deposited in the oocyte, or female germ cell involved in reproduction

Where does the yolk come from in vitellogenesis?

Vitellogenesis. Vitellogenesis (also known as yolk deposition) is the process of yolk formation via nutrients being deposited in the oocyte, or female germ cell involved in reproduction of lecithotrophic organisms.

How is vitellogenesis regulated in an oviparous animal?

HORMONAL REGULATION OF VITELLOGENESIS In oviparous animals, embryos are dependent on the egg-yolk for their nutritional requirements. The process of yolk deposition in oocytes – vitellogenesis – is a seasonal or cyclic phenomenon.

How is vitellogenesis related to choriogenesis in fishes?

Vitellogenesis and choriogenesis in fishes. Fisheries Science 82, 187–202. Vitellogenesis, a phase of accelerated egg growth leading to the production of fully grown eggs, involves the massive accumulation of protein and lipid yolk, often within a short period of time.