Biology Questions

Plant development is influenced by quality, quantity and duration of light. Plants cannot get too much light, but they can get too much of the heat energy that comes with the light.

Plants requires what quantity of light?

* Most of the garden vegetables require full sun, i.e 6 - 8 hrs of direct sunlight daily.

* Plants that grow in partial sun only need 3 - 4 hrs of direct sunlight daily.

* While plants that thrive in shade need less than 2 hours of sunlight daily.

A tetrad is formed from two homologous chromosomes, each consisting of two chromatids in the first stage of meiosis called prophase1.

The feeding mechanism is of several types.If it is entirely plant-like (photosynthesis), it is called holophytic. It is entirely (holo) animal-like(zoic),that is devouring alreadyexisting food, it is called holozoic

Aerobic respiration is the reaction takes place in presence of oxygen which quite opposite to anerobic. The direct result of aerobic repiration is ATP molecules from breakdown of glucose molecules.

The term 'Vector' in recombinant DNA methods, refers to a plasmid or other agent used to transfer DNA into a living cell.

Meiosis ::

Meiosis is a type of cell division that reduces the chromosome number by half in daughter cells, creating four haploid cells, each genetically distinct from the parent cell that gave rise to them.

Why it is called as Reduction Division ::

1. As the Meiosis division process involves in reduction of chromosome number in the daughter cells to half the number in the parent cell, this process is called Reduction Division.
Meiosis creates gametes (egg and sperm cells).

2. The resulting gametes have 23 new chromosomes, one member of each of the 23 pairs, representing unique combinations of the original maternal and paternal copies.

The receptor molecules, which receive signals from outside the cell, passing the signal to the inside.

In order for a nerve cell, or any cell, to perceive its environment, it needs a sensory apparatus. And for an individual cell, most of that sensation is derived at the cell surface. So, it expresses on its cell surface proteins that span across the membrane.

In the outside world, these proteins can act to receive signals, catching molecules on the outside and then as the molecule passes to the inside of the cell, they can send signals like alarm signals that can tell the cell that a particular molecule is outside.

Hence, here B is the receptor cell.