During the menstrual phase of the menstrual cycle, the zona pellucida develops around each egg.
The menstrual cycle is count from the first day of one period to the first day of the next period. The menstrual cycle differs in all women. This cycle has four main phases namely the follicular phase, ovulation phase, luteal phase and the menstrual phase.
The follicular phase starts on day one. The follicle stimulating hormone or FSH and estrogen rise. This is followed by the ovulation phase in which the egg is released. In the luteal phase corpus luteum produces progesterone and estrogen. In the menstrual phase of the menstrual cycle, the zona pellucida develops around each egg.
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When something needs to be transported against its concentration gradient, or a molecule is too big to simply diffuse through a membrane, active transport has to be used. So active transport requires energy (ATP).
Examples:
1. Antiport pumps: transport one substance in one direction while transporting another substance the other way. An example of this is the sodium-potassium pump.
2. Symport pumps - uses a substance that wants to move from an area of high concentration to low concentration and carries another substance against its concentration gradient. An example of this is the sodium-glucose transport protein
3. Endocytosis - large amounts of extra cellular fluid can be taken into a cell - needs ATP to bind proteins in the cell membrane and causes them to change their shape...which eventually causes the surrounding of the fluid to be brought in (a vesicle).
4.exocytosis - opposite of above
Answer:
Pasteur disproved the theory of spontaneous generation through his tests.
Explanation:
Hope this helps!
Cell membrane allows some material to pass through it while on the same time it blocks other material from entering through it
1. Intensity.
2. Duration of shaking.
3. Nature of material upon which structure rests.
4. Nature of building materials and the construction practices of region.
