Biology Test 318

• In pure state, chlorophyll b is olive-green. In pure state, chlorophyll a is blue-green.
• Chlorophyll b is an accessory photosynthetic pigment.
• Chlorophyll a is a primary photosynthetic pigment.
• Chlorophyll b absorbs more violet-blue wavelength than red wavelength of light.
• Chlorophyll a absorbs more red wavelength than violet-blue wavelength of light.
• Chlorophyll b is soluble in 92% methyl alcohol.

RuBisCO that is the most abundant enzyme in the world and is characterised by the fact that its active site can bind to both CO₂ and O₂ hence the name.

Photosynthesis takes place only in the green parts of the plants, mainly the leaves.

Phylurm Mollusca includes those animals which have a soft body, usually furnished with a shell. The body is divided into a head, muscular foot and visceral mass. Loligo (squid), Teredo (shipworm) and Octopus are some of its examples.

Nereis belongs to phylum Annelida and scorpion, cockroach and silver fish belong to phylum Arthopoda. They all possess dorsal heart.

Arthropods show various body shapes with bilateral symmetry. They show incomplete metameric segmentation. They have true coelom containing haemocoel. In arthropods, blood vascular/circulatory system is of open type where blood flows in haemocoel instead of blood vessels.

A body cavity can mean any Interna space, or a series of spaces present inside body, whereas coelom or true body cavity generally refers to a large fluid-filled space (cavity) lying between the outer body wall and the inner digestive tube. In acoelomates no body cavity or coelom is present. Embryonic mesoderm remains as a solid layer, space between endoderm (gut wall) and ectoderm (body wall) is filled with mesenchyme and muscle fibres. In pseudocoelomates body space is a pseudocoelom or false coelom. In coelomates or eucoelomates body space is a true coelom enclosed by mesoderm on both sides. Aschelminthes are pseudocioelomates Molluscs and insects are coelomates while flatworms are acoelomates.

In sponges, sexes are not separate (hermaphrodite) i.e., eggs and sperms are produced by the same individuals. Sperms leave one sponge and enter another with water current to fertilize the ova (eggs) in situ. Thus, fertilization is internal.

Members of phylum Mollusca have non-segmented body with a distinct head, muscular foot and visceral hump. A soft and spongy layer of skin forms a mentle over the visceral hump. The other characteristics  mentioned in  other options are shared with other phyla e.g. bilateral symmetry is exhibited by phylums Platyhelminthes, Aschelminthes, Annelida And Arthropoda.

Segmentation is division or differentiation of the body into distinct portions called segments. It is first observed phylum Annelida.