BIOLOGY 2 Marks Questions

i. It shows the decomposition of water molecule. It takes place in PS II. It is located on the inner surface of thylakoid membrane.
ii. Splitting of water continuously provides electrons to the electron transport chain; for further steps of photosynthesis.

In the absence of light, chlorophyll production decreases in leaves, leading to a reduction in the green pigment content. This causes the leaf to appear yellow or pale green. Carotenoids are more stable than chlorophyll.

Exotic species are introduced into a new area like E. crassipes that damages our nature species.
Endemic species are confined to a region and not found anywhere else.

Four Activities Regulated by Estrogen Hormone are:
i. The stimulation and growth of secondary sex organs.
ii. The development of growing follicles.
iii. The appearance offemale secondary sexual characteristics like voice pitcofh is high, mammary glands development and other features, etc.
iv. To regulate female sexual behaviour.

Monocot Leaf
Symmetry: Isobilateral
Stomata distribution: Amphistomatic i.e., stomata equally distributed on both the surfaces.
Bulliform cells: Present on upper epidermis.
Mesophyll: Only spongy parenchyma is present which has very small intercellular spaces.
Bundle sheath: Made of parenchyma but just above and below the vascular bundles are found sclerenchymatous cells (upto epidermis)
Dicot Leaf
Symmetry: Dorsiventral
Stomata distribution: Hypostomatic i.e., stomata present on lower surface of leaf.
Bulliform cells: Usually absent.
Mesophyll: Made up of two types of tissues: Palisade parenchyma and spongy parenchyma with large intercellular spaces. Bundle sheath: Made up of parenchyma. Just above and below the vascular bundle some parenchymatous cells or collenchymatous cells are present up to epidermis.