GATE Questions

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The number of bonds between a pair of atoms is called the bond order.

Bond orders can be calculated from Lewis structures, which are the heart of the valence-bond model. Oxygen, for example, has a bond order of two.

When there is more than one Lewis structure for a molecule, the bond order is an average of these structures. The bond order in sulfur dioxide, for example, is 1.5  the average of an S-O single bond in one Lewis structure and an S=O double bond in the other.

In molecular orbital theory, we calculate bond orders by assuming that two electrons in a bonding molecular orbital contribute one net bond and that two electrons in an antibonding molecular orbital cancel the effect of one bond. We can calculate the bond order in the O₂ molecule by noting that there are eight valence electrons in bonding molecular orbitals and four valence electrons in antibonding molecular orbitals in the electron configuration of this molecule. Thus, the bond order is two.

It is useful to have a property of a material that is independent of the size of the sample and can be use to compare its elastic properties with another - this is called the Modulus of Elasticity for the material.

The modulus of elasticity is defined as:

Modulus of elasticity = Stress / Strain

There are three types of moduli. They are :

(a) the Young Modulus - tensile and compression longitudinal stress

(b) the shear modulus - a shearing stress

(c) the bulk modulus - volume changes of the specimen.

We park car temporarily in garrage, similarly, aeroplane is temporarily parked in hangar.

SHORT is the required five letter word, which becomes SHORTER when two letters 'ER' are added to it.

A bootstrap is the process of starting up a computer. It also refers to the program that initializes the operating system (OS) during start-up.

It referred to a bootstrap load button that was used to initiate a hardwired bootstrap program, or smaller program that executed a larger program such as the OS.

All of the genetic information in a cell was initially thought to be confined to the DNA in the chromosomes of the cell nucleus.

It is now known that small circular chromosomes, called extranuclear, or cytoplasmic, DNA, are located in two types of organelles found in the cytoplasm of the cell.

These organelles are the mitochondria in animal and plant cells and the chloroplasts in plant cells.

Chloroplast DNA (cpDNA) contains genes that are involved with aspects of photosynthesis and with components of the special protein-synthesizing apparatus that is active within the organelle.

Mitochondrial DNA (mtDNA) contains some of the genes that participate in the conversion of the energy of chemical bonds into the energy currency of the cell—a chemical called adenosine triphosphate (ATP)—as well as genes for mitochondrial protein synthesis.