Why are vascular bundles closed in monocots? from Biology NEET Y

Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

Vitamin B6 is also called

  • thiamine

  • pantothenic acid

  • pyridoxine

  • retinol


2.

Protista differs from monera in having

  • cell wall

  • autotrophic nutrition

  • flagella

  • nuclear membrane


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3.

Why are vascular bundles closed in monocots?

  • Xylem and phloem are present.

  • Xylem and phloem occur in separate bundles.

  • Vascular cambium is present between xylem and phloem.

  • Vascular cambium is not present.


D.

Vascular cambium is not present.

The vascular system consists of complex tissues, the phloem and the xylem.

The xylem and phloem together constitute vascular bundles. In dicotyledonous stems, cambium is present between phloem and xylem. Such vascular bundles because of the presence of cambium possess the ability to form secondary xylem and phloem tissues, and hence are called open vascular bundles. In the monocotyledons, the vascular bundles have no cambium present in them. Hence, since they do not form secondary tissues so they are referred to as closed.


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4.

Who invented electron microscope?

  • Janssen

  • Edison

  • Knoll and Ruska

  • Landsteiner


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5.

What do A, B, C and D represent in the following figure?

  • A : carrier protein, B: symport, C: uniport, D : antiport

  • A : carrier protein, B : uniport, C: antiport, D : symport

  • A: carrier protein, B: antiport, C: symport, D : uniport

  • A : carrier protein, B: uniport, C: symport, D : antiport


6.

Gametophyte and sporophyte are independent of each other in which of the following groups?

  • Pteridophytes

  • Angiosperms

  • Gymnosperms

  • Bryophytes


7.

Which of the following is correct?

  • Paneth cells secrete pepsinogen

  • Parietal cells secrete hydrochloric acid

  • Argentaffin cells secrete mucus

  • Chief cells secrete gastrin


8.

Which of the following is correct about the given figure?

  • The length ofthe thick and thin myofilaments has changed.

  • Length of both anisotropic and isotropic band has changed.

  • The myosin cross-bridges move on the surface of actin and the thin and thick myofilaments slide past each other.

  • Length of the sarcomere remains same.


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9.

What is correct about the movement of substance across the membrane in facilitated diffusion?

  • It is an active transport

  • It doesn't cause transport of molecules from low concentration to high concentration

  • It is insensitive to inhibitors

  • It is a very specific transport


10.

Refer the given figures on photoperiodism and select the correct option.

  • A B C
    no correlation between light period and flowering long light- exposure period short light- exposure period
  • A B C
    long light- exposure period no correlation between light period and flowering short light- exposure period
  • A B C
    short light exposure period long light exposure period no correlation between light period and flowering
  • A B C
    no correlation between light period and flowering short light exposure period long light exposure period

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