Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

Cholesterol is a precursor for each of the following except

  • bile salts

  • vitamin D

  • insulin

  • steroids


C.

insulin

Cholesterol is a precursor of most steroid hormones like progesterone, estradiol, aldosterone, cortisol etc. Cholesterol forms vitamin D on UV exposure  and it also helps in forming bile salt


2.

Which of the following groups of algae produces algin?

  • Phaeophyceae and Chlorophyceae

  • Rhodophyceae and Phaeophyceae

  • Chlorophyceae and Rhodophyceae

  • Phaeophyceae only


D.

Phaeophyceae only

Alginic acid(or algin or alginate) is an anionic polysccharide distributed widely in the cell walls of many brown algae (Phaeophyceae). It is a phycocolloid which is obtained commercially from Laminaria, Macrocystis, Nereocystis, Fucus, Sagrassum etc.


3.

Which one of the following is an incorrect combination

  • Adenine, thymine, cytidine

  • Adenine, cytosine, thymine

  • Guanine, thymine, uracil

  • Cytosine, uracil, guanine


A.

Adenine, thymine, cytidine

Adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U) are all nitrogenous bases, whereas cytidine is a nucleoside i.e., a combination of a nitrogenous base (cytosine) with a pentose sugar (ribose).


4.

Which part of the nephrons is impermeable to water

  • Proximal convoluted tubule

  • Distal convoluted tubule

  • Ascending limb of loop of Henle

  • Descending limb of loop of Henle


C.

Ascending limb of loop of Henle

Ascending limb of loop of Henle is impermeable to water. It does not reabsorb water, rather sodium, potassium, magnesium and chloride are reabsorbed and therefore the filtrate becomes hypotonic to blood plasma


5.

Match the following and select correct option.

  Column1        Column2

A. Pteris           1) Gymnosperm

B. Cycas           2) Bryophyte

C. Sphagnum    3) Algae

D. Sargassum   4) Pteridophyta

  • A-(4), B-(2), C-(1), D-(3)

  • A-(4), B-(1), C-(2), D-(3)

  • A-(2), B-(3), C-(4), D-(1)

  • A-(1), B-(4), C-(3), D-(2)


B.

A-(4), B-(1), C-(2), D-(3)


6.

Gonadotropin releasing hormone is transferred to anterior pituitary by

  • left coronary artery

  • hypophysial portal veins

  • axons of neurosecretory cells

  • nuclei of hypothalamus


B.

hypophysial portal veins

Hypothalamus is connected to the anterior lobe of pituitary gland by hypophysial portal veins. The latter carry blood containing neurohormones (releasing factors) from the hypothalamus to the anterior lobe of the pituitary.


7.

Hiccups can be best described as

  • forceful sudden expiration

  • forceful contraction of intercostal muscles during deep breathing

  • vibration of the soft palate during breathing while sleeping

  • jerky incomplete inspiration.


D.

jerky incomplete inspiration.

A hiccup can be described as a jerky incomplete inspiration. It is an involuntary contraction of the diaphragm that may repeat several times per minute. In medical terms, it is known as synchronous diaphragmatic flutter (SDF).


8.

The 1st COfixation product of Cplant is

  • Oxaloacetic acid

  • ribulose biphosphate

  • phosphoenolpyruvate

  • phosphoglyceric acid.


A.

Oxaloacetic acid

In C4 Plants, initial fixation of carbon dioxide occurs in mesophyll cells. The primary acceptor of CO2 i.e. phosphoenol pyruvate (PEP) combines with CO2 in the presence of PEP carboxylase or PEPcase to form oxaloacetic acid, which is the first stable carbon dioxide fixation product in Cpathway.


9.

Mature RBCs lose their ability for

  • DNA replication

  • Anaerobic respiration

  • Aerobic respiration and DNA replication

  • Aerobic respiration, DNA replication and RNA synthesising machinery


D.

Aerobic respiration, DNA replication and RNA synthesising machinery

Matured mammalian RBCs do not have cell organelles including nucleus, Golgi bodies, mitochondria, ribosomes, centrioles and endoplasmic reticulum. It increases the surface area of RBCs and enables them to contain more haemoglobin. In the absence of cell organelles, the consumption of oxygen is very low and thus anaerobic respiration occurs in RBCs. Mature RBCs cannot replicate and cannot synthesise RNA as they do not possess machinery required (e.g., various enzymes) for replication and RNA synthesis.


10.

Which of the following genera is associated with coralloid roots?

  • Cycas

  • Taxus

  • Pinus

  • Sequoia


A.

Cycas

Roots in Cycas are of two types- normal and coralloid roots. Coralloid roots are irregular, negatively geotropic, dichotomously branched coral like roots which do not possess root hairs and root caps. Coralloid roots have a symbiotic association with blue-green algae like Nostoc and Anabaena species