Microtubules are the constituent of

• spindle fibres, centrioles and cilia

• centrioles, spindle fibres and chromatin

• centrosome, nucleosomes and centrioles

• centrosome, nucleosomes and centrioles

Mitochondria and choloroplast are :
I. semi-autonomous organelles.
II. formed by division of pre-existing  organelles and they contain DNA but lack protein synthesizing machinery. 

• II is true but I is false

• I is true but II is false

• Both I and II are false

• Both I and II are false

Photosensitive compound in human eye is made up of

• opsin and Retinal

• opsin ans Retinol

• transducin and Retinene

• transducin and Retinene

4.

Chrysophytes, euglenoids, dinoflagellates and slime moulds are included in the kingdom

• Protista

• Fungi

• Animalia

• Animalia

The primitive prokaryotes responsible for the production of biogas from the dung of ruminant animals, include the 

• thermoacidophiles

• methanogens

• eubacteria

• eubacteria

Which of the following characteristic features always holds true for the corresponding group of animals?

• Viviparous

  Mamalia

• Posess a mouth with an upper and lower jaw

  Chordata

• 3-chmbered heart with one incompletely divided ventricle

  Reptilia

• Cartiliginous- endoskeleton

  Chondrichthyes

Tricarpellary, syncarpous gynoecium is found in flowers of

• Solanaceae

• Fabaceae

• Poaceae

• Poaceae

In which of the following, all three are macronutrients

• Iron, copper, molybdenum

• Molybdenum, magnesium, manganese

• Nitrogen, nickel, phosphorous

• Nitrogen, nickel, phosphorous

Reduction in pH of blood will

• reduce the blood supply to the brain

• decrease the affinity of haemoglobin with oxygen

• release bicarbonate ions by the liver

• release bicarbonate ions by the liver

Lack of relaxation between successive stimuli in sustained muscle contraction is known as

• fatigue

• tetanus

• tonus

• tonus