Function of copanion cells is  from Biology NEET Year 2011 Fre

Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort?

  • One can breathe out air totally without oxygen

  • One can breathe out air through eustachian tubes by closing both the nose and the mouth

  • One can consously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all

  • One can consously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all

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2.

Which one of the following statements is totally wrong about the occurrence of the notochord, while the other three are correct? 

  • It is present only in larval tail in Ascidians

  • It is replaced by a vertebral coloumn in adult frog

  • It is absent throughout life in humans from the very beginning

  • It is absent throughout life in humans from the very beginning

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3.

The cells lining the blood vessels belong to  the category of 

  • smooth muscle tissue

  • squamous epithelium

  • columnar epithelium

  • columnar epithelium

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4.

The pathogen Microsporum responsible for ringworm disease in humans belongs to the same kingdom of organisms as that of 

  • Taenia, a tapewarm

  • Wuchereria, a filarial worm

  • Rhizopus, a mould

  • Rhizopus, a mould

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5.

At metaphase, chromosomes are attached to the spindle fibres by their

  • satellites

  • Secondary constrictions

  • Kinetochores

  • Kinetochores

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6.

One of the constituents of the pancreatic juice while poured into the duodenum in humans, is

  • Trypsinogen

  • chymotrypsin

  • trypsin

  • trypsin

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7.

Frogs differ from humans in possessing

  • paired cerebral hemispheres

  • chymotrypsin

  • trypsin

  • trypsin

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8.

Function of copanion cells is 

  • providing energy to sleve elements for active transport

  • Providing water to phloem

  • loading of sucrose into sieve elements by passive transport

  • loading of sucrose into sieve elements by passive transport


D.

loading of sucrose into sieve elements by passive transport

The companion cells are specialised parenchyma cells, which are closely associated with sieve tube elements. The sieve tube elements and companion cells help in maintaining the pressure gradient in the sieve tubes. they also function in the loading of sucrose into sieve elements actively.

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9.

Some vascular bundles are described as open because these

  • are surrounded by pericycle but no endodermis

  • are capable of producing secondary xylem and phloem

  • Possess conjunctive tissue between xylem and phloem

  • Possess conjunctive tissue between xylem and phloem

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10.

In mitochondria, protons accumulate in the 

  • outer membrane

  • inner membrane

  • intermembrane space

  • intermembrane space

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