NEET Practice Questions (MCQs) with Answers & Solutions

The NCERT text defines position isomerism as compounds differing 'in the position of substituent atom or functional group on the carbon skeleton'. Propan-1-ol ($CH_3CH_2CH_2OH$) and Propan-2-ol ($CH_3CH(OH)CH_3$) have the same carbon skeleton and functional group (-OH), but the position of the -OH group is different. But-1-ene and 2-Methylprop-1-ene are chain isomers (or skeletal isomers). Diethyl ether and Butan-1-ol are functional group isomers. n-Butane and Isobutane are also chain isomers.

As per the NCERT text, 'Lower invertebrates like sponges, coelenterates, flatworms, etc., exchange O2 with CO2 by simple diffusion over their entire body surface.'

The context states: 'Special vascularised structures called gills (branchial respiration) are used by most of the aquatic arthropods and molluscs...'

According to the NCERT text, 'Amphibians like frogs can respire through their moist skin (cutaneous respiration) also.' And from Structural Organisation in Animals: 'In water, skin acts as aquatic respiratory organ (cutaneous respiration). ... On land, the buccal cavity, skin and lungs act as the respiratory organs.'

The NCERT text states: 'The part starting with the external nostrils up to the terminal bronchioles constitute the conducting part... The conducting part transports the atmospheric air to the alveoli, clears it from foreign particles, humidifies and also brings the air to body temperature.'

The NCERT text specifies: 'Exchange part [alveoli and their ducts] is the site of actual diffusion of O2 and CO2 between blood and atmospheric air.' Also, 'Alveoli are the primary sites of exchange of gases.'

The NCERT states: 'Tidal Volume (TV): Volume of air inspired or expired during a normal respiration. It is approx. 500 mL.'

According to the NCERT text: 'Residual Volume (RV): Volume of air remaining in the lungs even after a forcible expiration. This averages 1100 mL to 1200 mL.'

The NCERT defines Vital Capacity (VC) as: 'The maximum volume of air a person can breathe in after a forced expiration. This includes ERV, TV and IRV or the maximum volume of air a person can breathe out after a forced inspiration.'

The NCERT states: 'The diffusion membrane is made up of three major layers... namely, the thin squamous epithelium of alveoli, the endothelium of alveolar capillaries and the basement substance (composed of a thin basement membrane supporting the squamous epithelium and the basement membrane surrounding the single layer endothelial cells of capillaries) in between them.'