Biology Questions

Enzymes are macromolecular biological catalysts. Enzymes accelerate chemical reactions. The molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products.

Cellular respiration can be broken down into three main steps:

1. Glycolysis,

2. The Kreb's cycle (The citric acid cycle), and

3. Electron Transport Chain.

A chromatid is one copy of a newly copied chromosome which is still joined to the original chromosome by a single centromere.

The two identical copies—each forming one half of the replicated chromosome are called chromatids.

Chromonema is the fibre-like structure in prophase in the primary stage of DNA condensation. In metaphase, they are called chromatids.

The nervous system of the human brain consists of the central nervous system which has brain and the spinal cord and the peripheral nervous system which has perpheral, cranary, spinal nerves.

Asterias has bilateral symmetry only at larval stagebut fivefold symmetry (pentamerism, a special type of radial symmetry) as adults.

Nereis do not possess any symmetry elements in their body organisation.

"If fertilization occurs, the corpus luteum is maintained by a hormone secreted by the developing embryo." is the only correct statement about the uterine cycle among the options.

Goosebumps are caused by the contraction of the tiny muscles attached to hair follicles. These muscles are arrectores pilorum muscles.