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NEET - 2021 Previous Year Questions



NEET Biology Previous Year Questions - 2021

Which stage of meiotic prophase shows terminalisation of chiasmata as its distinctive feature?

NEET-2021 [Cell-Cycle-and-Cell-Division] [class-xi ]

  • Leptotene
  • Zygotene
  • Diakinesis
  • Pachytene
  • Correct Option: C  [ Diakinesis ]

    Remark:

The centriole undergoes duplication during:

NEET-2021 [Cell-Cycle-and-Cell-Division] [class-xi ]

  • S-phase
  • Prophase
  • Metaphase
  • G2 phase
  • Correct Option: A  [ S-phase ]

    Remark:

Succus entericus is referred to as:

NEET-2021 [Digestion-and-Absorption] [class-xi ]

  • Pancreatic juice
  • Intestinal juice
  • Gastric juice
  • Chyme
  • Correct Option: B  [ Intestinal juice ]

    Remark:

Sphincter of oddi is present at:

NEET-2021 [Digestion-and-Absorption] [class-xi ]

  • Ileo-caecal junction
  • Junction of hepato-pancreatic duct and duodenum
  • Gastro-oesophageal junction
  • Junction of jejunum and duodenum
  • Correct Option: B  [ Junction of hepato-pancreatic duct and duodenum ]

    Remark:

The partial pressures (in mm Hg) of oxygen (O2) and carbon dioxide (CO2) at alveoli (the site of diffusion) are :

NEET-2021 [Breathing-and-Exchange-of-Gases] [class-xi ]

  • pO2 = 104 and pCO2 = 40
  • pO2 = 40 and pCO2 = 45
  • pO2 = 95 and pCO2 = 40
  • pO2 = 159 and pCO2 = 0.3
  • Correct Option: A  [ pO2 = 104 and pCO2 = 40 ]

    Remark:

Select the favourable conditions required for the formation of oxyhaemoglobin at the alveoli.

NEET-2021 [Breathing-and-Exchange-of-Gases] [class-xi ]

  • High pO2, low pCO2, less H+, lower temperature
  • Low pO2, high pCO2, more H+, higher temperature
  • High pO2, high pCO2, less H+, higher temperature
  • Low pO2, low pCO2, more H+, higher temperature
  • Correct Option: A  [ High pO2, low pCO2, less H+, lower temperature ]

    Remark:

Which enzyme is responsible for the conversion of inactive fibrinogens to fibrins?

NEET-2021 [Body-Fluids-and-Circulation] [class-xi ]

  • Thrombin
  • Renin
  • Epinephrine
  • Thrombokinase
  • Correct Option: A  [ Thrombin ]

    Remark:

Persons with 'AB' blood group are called as "Universal recipients". This is due to:

NEET-2021 [Body-Fluids-and-Circulation] [class-xi ]

  • Absence of antigens A and B on the surface of RBCs
  • Absence of antigens A and B in plasma
  • Presence of antibodies, anti-A and anti-B, on RBCs
  • Absence of antibodies, anti-A and anti-B, in plasma
  • Correct Option: D  [ Absence of antibodies, anti-A and anti-B, in plasma ]

    Remark:

Chronic auto immune disorder affecting neuro muscular junction leading to fatigue, weakening and paralysis of skeletal muscle is called as:

NEET-2021 [Locomotion-and-Movement] [class-xi ]

  • Arthritis
  • Muscular dystrophy
  • Myasthenia gravis
  • Gout
  • Correct Option: C  [ Myasthenia gravis ]

    Remark:

Erythropoietin hormone which stimulates R.B.C. formation is produced by:

NEET-2021 [Chemical-Coordination-and-Integration] [class-xi ]

  • Alpha cells of pancreas
  • The cells of rostral adenohypophysis
  • The cells of bone marrow
  • Juxtaglomerular cells of the kidney
  • Correct Option: D  [ Juxtaglomerular cells of the kidney ]

    Remark: