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NEET Biology Solved Question Paper 2013

Multiple Choice Questions

11.

Which of the following inhibits O₂ release in light phase?

Zeatin
PMA
DCMU
None of these

DCMU

DCMU is a very specific and sensitive inhibitor of photosynthesis (photosynthetic inhibitors). It blocks the plastoquinone binding site of photosystem II, disallowing the electron flow from photosystem II to plastoquinone. Thus, it inhibits Hill reaction, by inhibiting release of O₂.

12.

When the organic acid is oxidised in respiration, the value of R.Q. becomes

zero
one
less than one
more than one

more than one

When an organic acid is oxidised the value of R.Q. in respiration becomes more than one. Because organic acids are rich in O₂ and require less O₂ for their oxidation. It is clear from the equation given below.

C₄H₆O₅ (Malic acid) + 3O₂ $\to$ 4CO₂ + 3H₂O

$∴$ R.Q. = $\frac{Volume of {CO}_{2} evolved}{Volume of O_{2} taken} = \frac{4}{3}$

R.Q = 1.3 (more than one)

13.

Bilirubin and biliverdin are

enzymes
bile salts
bile pigments
None of these

bile pigments

Bilirubin and biliverdin are the break down products of haemoglobin formed by the liver and secreted in the bile to be stored in the gall-bladder. They are required for digestion and absorption of fats.

14.

ABO blood grouping is controlled by gene I which has three alleles and show co-dominance. There are six genotypes. How many phenotypes in all are possible?

Three
Six
Five
Four

Four

The six genotypes are as follows:

I^AI^A or I^Ai or I^BI^B or I^Bi or I^AI^Bor ii

15.

Auxin was first named by

C Darwin
FW Went
Alexopolus
KV Thimann

FW Went

FW Went (1928) was the first person to name auxins. Thimann (1936) isolated IAA from Rhizopus sinus and Avena coleoptiles.

16.

The nitrifying bacteria that convert the ammonia to nitrates are

Nitrosomonas and Nitrobacter
Azotobacter
Rhizobium sp.
Thiobacillus denitrificans

Nitrosomonas and Nitrobacter

Nitrification is the phenomenon of conversion of ammonium to nitrate by nitriflying bacteria like Nitrosomonas, Nitrobacter, etc. It occurs in two steps-

2NH₃ + 3O₂ $\overset{N i t r o s o m o n a s}{\to}$ 2NO^-₂ + 2H⁺ + 2H₂O + Energy

2NO^-₂ + O₂ $\overset{N i t r o b a c t e r}{\to}$ 2NO^-₃ + Energy

17.

Ivan Pavlov performed experiments on

origin of life
cardiac reflexes
simple reflexes
conditioned reflexes

conditioned reflexes

Conditioned reflex is an automatic response established by training to an ordinarily neutral stimulus. They were first demonstrated in 1920s by the Russian physiologist I.P. Pavlov. He found that the sight and smell of food reflexly cause flow of saliva in hungry animals.

18.

Marasmus in children is caused by deficiency of

protein
fats
vitamins
carbohydrates

protein

Marasmus is a protein energy malnutrition disorder. It is found in infants due to lack of proper diet of protein and calories. It is also in case of less breast feeding diet. Due to this body become lean and weak, eyes depressed and skin wrinkled.

19.
According to Boyle's law, the product of pressure and volume is a constant. Hence,

if volume of lungs is increased, the pressure decreases disproportionately

if volume of lungs is increased, the pressure remains the same

if volume of lungs is increased, the pressure decreases proportionately

if volume of lungs is increased, the pressure also increases proportionately

if volume of lungs is increased, the pressure decreases proportionately

Boyle's law states that the pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature. Hence, if volume of lungs is increased, the pressure decreases proportionately.