Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

Which is not a gonadal hormone

  • Progesterone

  • Testosterone

  • Adrenalin

  • Estrogen


C.

Adrenalin

Adrenaline is produced in the medulla in the adrenal glands as well as some of the central nervous system's neurons. Within a couple of minutes during a stressful situation, adrenaline is quickly released into the blood, sending impulses to organs to create a specific response.


2.

Cerebrospinal fluid is present

  • beneath the pia mater

  • between piamater and arachnoid

  • between arachnoid and duramater

  • between duramater and cranium


C.

between arachnoid and duramater

CSF occupies the subarachnoid space (between the arachnoidmaterand the piamater) and the ventricular system around and inside the brain and spinal cord. It fills the ventricles of the brain, cisterns, and sulci, as well as thecentralcanal of the spinal cord.


3.

Antifeedant property occurs in

  • nicotine

  • azadiractin

  • rotenone

  • cinerin


B.

azadiractin

Antifeedantsare organic compoundproduced by plants to inhibit attack by insects and grazing animals. These chemical compounds are typically classified as secondary metabolitesin that they are not essential for the metabolism of the plant, but instead confer longevity. Antifeedants exhibit a wide range of activities and chemical structures as biopesticides.

Azadirachtin are extractof neem tree, ithas several effects on phytophagous insects and is thought to disrupt insect molting by antagonizing the effects of ecdysteroids. This effect is independent of feeding inhibition, which is another observed effect of the compound.1,10The antifeedant/repellent effects are dramatic, with many insects avoiding treated crops, although other chemicals in the seed extract, such as salanin, have been shown to be responsible for these effects.


4.

The crystal of lead zirconate is a key component of

  • sonography

  • electrocardiography

  • electroencephalography

  • magnetoencephalography


A.

sonography

The correct option is Sonography. is a process to visualize the structures beneath the skin. A gel containing the Lead Zirconate is used to prevent sound from getting scattered. It assists to diagnose cysts, tumors and many other complications.


5.

Cochlea of mammalian internal ear is concerned with

  • hearing

  • balance of body posture

  • both (a) and (b)

  • perception changes of atmospheric pressure


A.

hearing

Thecochleais a portion of the inner ear that looks like a snail shell (cochleais Greek for snail.) Thecochleareceives sound in the form of vibrations, which cause the stereocilia to move. The stereocilia then convert these vibrations into nerve impulses which are taken up to the brain to be interpreted.


6.

The dendrite carries impulses

  • towards the cyton

  • away from cyton

  • across the body

  • from one neuron to another


A.

towards the cyton

DendritesReceive STIMULUS (Action Potentials) andcarry IMPULSESfrom the ENVIRONMENT or from other NEURONS ANDCARRYTHEM TOWARD THECELL BODY. HoweverAXON – A Long Fibre thatCARRIES IMPULSESAWAY FROM THECELL BODY. Each neuron has only ONE AXON. The Axon Ends in a series of small swellings called AXON TERMINALS.


7.

Antibiotic flavicin is obtained from

  • Aspergillus flavus 

  • Aspergillus clavatum

  • Streptomyces grieseus

  • Streptomyces fradiae


A.

Aspergillus flavus 

Aspergillus flavusis the fungi which grows on plants such as peanut plant. It is used in the production of the antibiotic Flavicin. It is alsoused to producethe carcinogenic substance Aflatoxin.


8.

The part of an eye which acts like a diaphragm of a photographic camera is

  • pupil

  • iris

  • lens

  • cornea


B.

iris

The iris of the eye is the thin, circular structure made of connective tissue and muscle that surrounds the pupil. The color of our eyes is determined by the amount of pigment in the iris apart from this the iris acts like the diaphragm of a camera and controls the size of the pupil. One muscle within the iris constricts the pupil in bright light (full sunlight, for example), and another iris muscle dilates (enlarges) the pupil in dim lighting and in the dark.


9.

Ethylene is a

  • gaseous hormone

  • gaseous enzyme

  • liquid-gas mixture

  • solid hormone


A.

gaseous hormone

Ethyleneis thought of as the aginghormonein plants. In addition to causing fruit to ripen, it can cause plants to die. It can be produced when plants are injured, either mechanically or by disease. Ethylene gasis used commercially to ripen tomatoes, bananas, pears, and a few other fruits postharvest


10.

'Climacteric' is

  • a phenomenon related to fruit ripening

  • the condition of a plant when all its fruits are almost ripe

  • the condition of a plant when most of its leaves have turned yellow

  • none of the above


A.

a phenomenon related to fruit ripening

The development of multi-cellular organisms begins from a single-celled zygote, which undergoes rapid cell division to form the blastula. The rapid, multiple rounds of cell division are termedcleavage. After thecleavagehas produced over 100 cells, the embryo is called a blastula.