Phytotron is a chamber in which plants can be grown in controlled condition

The cell cycle of eukaryotic cell is divided into following four phases.

(1) G₁ phase (first growth phase)

(2) S phase (synthesis phase)

(3) G₂- phase (second growth phase)

(4) M-phase (mitotic phase)

S-phase is the phase is cell cycle during which DNA is replicated.

Nucleus, Plastids, and mitochondria are double membrane bound cell organelles whereas Lysosome is covered by single membrane.

Fruit formation is the characteristic feature of Angiosperms. It is found in Brassica, Bryophytes, Pteridophytes, whereas Gymnosperms lack fruit like structure.

The chlorophylls are basically chelate salts of magnesium (Mg). The chlorophyll has a molecular formula C₅₅H₇₂O₅N₄Mg. This molecule is distinguishable into head of size 15 x 15 Å and a tail length of 20 Å. The head is made up of prophyrin ( a tetraphyrrole closed ring derivative) and the tail of phytol.

Plasma membrane or cell membrane is made up of approximately 60% protein and 40% lipids (by dry weight). However, the protein is found as low as 20% (human myelin) or as high as 70% (rat liver mitochondria). Carbohydrates range from 1 to 10 % in the form of glycoproteins or glycolipids.

In metacentric chromosomes centromere is present in the middle of chromosome.

In sub-metacentric chromosomes the centromere is submedian.

In Acrocentric chromosome centromere is sub terminal.

In Telocentric chromosome centromere is terminal.

CAM or Crassulacean Acid Metabolism  is found in succulent plants. In these plants CO₂ is accepted in night via Phosphoenol pyruvate carboxylase enzyme in mesophyll cells.

During night, stomata open and CO₂ is stored in vacuole in the form of malic acid. During day, it is decarboxylated and CO₂ is transfered to ribulose 1,5 biphosphate (RuBP) of the calvin cycle within the same cell.

Quiescent centre is present in root apex. Clowes found a reservoir of cells having low DNA, RNA and protein concentration in root apex. These cells do not divide but may become active or they can made to divide. Due to its inactivity, the quiescent centre is resistant to damages.

Gibberellin is responsible for mobilization of storage food during seed germination. After getting moisture, the embryo of seed releases gibberellins. It induces the alemone layer of endosperm to produce enzymes (e.g. $\mathrm{\alpha }$-amylase). These enzymes digest stored starch to mobilize sugars for germination.